ANTHROPOLOGICAL PAPERS OF THE AMERICAN MUSEUM OF NATURAL HISTORY

Number 97: 236 pp. March 6, 2012

Copyright © American Museum of Natural History 2012

ISSN 0065-9452

http://dx.doi.org/10.5531/sp.anth.0097

[PART 2 OF EPUB]

SEASONALITY AND HUMAN MOBILITY ALONG THE GEORGIA BIGHT

ELIZABETH J. REITZ, IRVY R. QUITMYER, AND DAVID HURST THOMAS

EDITORS AND CONTRIBUTORS

WITH CONTRIBUTIONS BY

C. Fred T. Andrus, Sarah G. Bergh, Nicole R. Cannarozzi, Gwendolyn D. Carroll, Carol E. Colaninno, Brendan J. Culleton, Chester B. DePratter, Kandace D. Hollenbach, Douglas S. Jones, Deborah Ann Keene, Douglas J. Kennett, Charles W. Lambert, J.W. Moak, Bruce M. Saul, C. Margaret Scarry, Gregory A. Waselkov, and Elizabeth S. Wing

Proceedings of the Fifth Caldwell Conference

St. Catherines Island, Georgia

May 14–16, 2010

CHAPTER 6: Molluscs as Oxygen-Isotope Season-of-Capture Proxies in Southeastern United States Archaeology

C. Fred T. Andrus

Oxygen isotope measurements in mollusc shells (fig. 6.1) are increasingly used to determine season of capture (SOC) in southeastern U.S. archaeological sites (e.g., Keene, 2004; Quitmyer, Jones, and Andrus, 2005; Andrus and Crowe, 2008; Thompson and Andrus, 2011). The basic rationale was initially outlined by Shackleton (1969; 1973, drawing from Emiliani et al., 1964). The method relies on the systematic variation of oxygen isotopes (expressed as δ18O values in parts per mil: ‰) in shells during ontogeny as a function of water temperature and local water δ18O. In turn, local water δ18O values are a function of fresh and salt water mixing and/or evaporation. Therefore, seasonal oscillations in shell δ18O can be detected in areas with consistent variation in seasonal water temperature and/or precipitation (assuming that these two variables do not interact to obscure a seasonal signal in a shell).

If only one of those two variables controls shell δ18O in a particular habitat, then SOC analysis is fairly simple (i.e., along desert coasts with almost no variation in δ18O[water] or tropical areas with little temperature variation but a pronounced rainy season leading to seasonal changes in δ18O[water]). In those comparatively rare coastal environments, a small number of δ18O samples near the edge of the shell can be analyzed for both absolute value and trend, and then a SOC estimate can be made (e.g., Jones et al., 2008). Most other coastal mollusc habitats are subject to regular variation in temperature and irregular variation in δ18O[water], thus complicating interpretation of shell δ18O data. In many regions tidal variation between geographically adjacent zones makes absolute δ18O values nearly useless for assessing SOC (e.g., Andrus and Crowe, 2008; Thompson and Andrus, 2011). In these cases, a seasonal trend in δ18O[shell] must be reconstructed through ontogeny and the most recent δ18O value (at the growing shell edge) can be assessed relative to the particular seasonal cycle experienced by the shell as it grew (for a more complete explanation of one method using this approach, see Andrus and Crowe, 2008, and Thompson and Andrus, 2011. This approach is depicted in fig. 6.2). In most habitats along the southeastern coast of North America (Atlantic and Gulf of Mexico), local δ18O[water] is highly variable and is not reliably seasonal (see data at http://cdmo.baruch.sc.edu/ for examples from the Atlantic coast, and http://www.mymobilebay.com/ for examples from the Gulf coast). Therefore, the more expensive and time-consuming sequential sampling approach is required.

Early in the use of isotope sclerochronology, it was noted that careful study of modern living examples of each species (or close analogs) is necessary to ensure correct interpretation of archaeological SOC data (e.g., Bailey, Deith, and Shackleton, 1983). Different mollusc species have characteristics that may render their isotope profiles more or less useful as seasonal proxies (i.e., if the shape of the δ18O curve becomes nonsinusoidal, seasons cannot be determined). δ18O values in most biogenic carbonates are influenced by multiple variables in addition to temperature and ambient δ18O[water]. These factors may include metabolic/kinetic effects (e.g., Owen, Kennedy, and Richardson, 2002), shell mineralogy (e.g., Cusack et al., 2008), shell structure (e.g., Cusack et al., 2008; Jones, 2010), variable growth rate, and growth cessations (e.g., Goodwin, Schöne, and Dettman, 2003) to name a few.

To illustrate, consider that molluscs commonly cease growing for portions of each year (e.g., Goodwin, Schöne, and Dettman, 2003; Schöne, 2008; Jones et al., 2010a). If molluscs in a midden were collected during a prolonged period in which there was no shell growth, then the SOC estimate would be inaccurate. If the growth cessation periods are brief and do not interrupt the general seasonal trends in δ18O, then the shell isotope profile can still be a useful SOC proxy. This may, however, limit the precision of the estimates. Large numbers of growth breaks may preclude effective use of the shell as an SOC indicator by distorting the seasonal δ18O oscillation to the point where it is not recognizably sinusoidal. Some growth cessations are regular and linked to a particular time of the year (e.g., Jones et al., 2010a), and thus may aid in the interpretation of δ18O profiles. Others may be arrhythmic (e.g., Cobb, Andrus, and Etayo-Cadvid, 2009) and may cause significant ambiguity in δ18O interpretations.

These and other complications need to be assessed for each taxon prior to making SOC estimates from archaeological contexts. This is usually accomplished by detailed growth and geochemical analyses of modern controlled collections of specimens. Such baseline data are time-consuming and expensive to collect, thus the accumulation of SOC proxy methods for species in a region may be slow. A number of useful SOC taxa are needed to assess a wide range of human subsistence practices and to reconstruct possible seasonal-round movements across habitats. For example, it must be remembered that an SOC estimate from a particular taxon does not necessarily equate to the total season(s) of site occupation. It is plausible that some resources would only be exploited seasonally in an otherwise permanent occupation, perhaps due to dietary prohibitions, comparative abundance of other food sources, seasonal changes in taste and condition of molluscs, or a number of other factors. In such cases, a single-taxon SOC study would yield erroneous conclusions. Furthermore, multispecies SOC data would also be useful in assessing regional subsistence strategies. For example, prehistoric people in the coastal southeastern United States exploited a wide range of habitats (e.g., Thomas, 2008). Few mollusc species are present in all of these habitats. To gain a more complete picture of regional site occupation patterns, data would be required from sites from all habitat zones.

To accomplish this broader approach in the southeastern United States, not only do we need an understanding of the abundant coastal marine/lower estuarine species like oyster and quahog, but also brackish and freshwater taxa. If reliable methods can be established for multiple taxa, then widespread and more cost-effective application of SOC estimates can be made, thus building a regional understanding of subsistence practices.

Fig. 6.1. Examples of taxa described in this chapter. A, American oyster (Crassostrea virginica); B, quahog (Mercenaria mercenaria); C, coquina (Donax variabilis); D, bay scallop (Argopecten irradians); E, ribbed mussel (Geukensia demissa); F, stout razor clam (Tagelus plebeius); G, marsh clam (Rangia cuneata); H, Carolina marsh clam (Polymesoda caroliniana); I, periwinkle (Littorina irrorata); J, knobbed whelk (Busycon carica); K, freshwater mussel (Unionidae).

Fig. 6.2. Idealized representation of seasonal δ18O oscillations in a mollusc through ontogeny.

Discussion

The goal of this chapter is to review published literature pertinent to oxygen isotope SOC assessment methods in the southeastern U.S. coastal zone. Each relevant taxon (fig. 6.1) will be discussed individually. In most cases these taxa have not been used to measure SOC yet, so their potential utility will be evaluated based on published literature and new data pertinent to key variables such as biogeography, taphonomy, shell structure and mineralogy, seasonal growth, and geochemistry. This is not meant to be a complete list of all molluscs found in southeastern middens, but rather focuses on taxa that are comparatively common in archaeological sites, display some potential for use as SOC indicators, and cover a wide range of ecosystems relevant to coastal subsistence. Not all of these species are present in St. Catherines Island middens, but all are found within nearby coastal ecosystems. For the purposes of this chapter, the “southeastern U.S. coast” includes all tidally affected water from the northernmost barrier islands of the Carolinas south to the semitropical zones of southern Florida, and in the Gulf of Mexico coast from semitropical Florida west to Mexico.

Oyster (Crassostrea virginica)

The oyster (see A in fig. 6.1) is the most common mollusc found in southeastern U.S. coastal middens (for examples see Pearson, 1977; Crook, 1992; Russo and Heide, 2001; Keene 2002; Quitmyer and Reitz, 2006; Thomas, 2008; Thompson and Andrus, 2011 ). Five studies have been published on oxygen isotope analyses in modern populations, Kirby, Soniat, and Spero (1998) Andrus and Crowe (2000) and Surge, Lohmann, and Dettman (2001), Harding et al. (2010) and Cannarozzi (chap. 10, this volume), as well as three isotopic SOC analyses of archaeological sites, Keene (2004), Harding et al. (2010), and Thompson and Andrus (2011).

Oysters present several significant challenges unique among common southeastern U.S. midden molluscs. Most obvious is their highly variable morphology. Whereas most molluscs grow in generally predictable rates and shapes like Mercenaria spp. (see Quitmyer, Jones, and Arnold, 1997; compare A and B in fig. 6.1), oysters do not have a specific growth geometry (see Kent, 1982). As such, oysters are not typically sampled for oxygen isotopes across the valve length as is the case in most taxa, but rather are bisected along the chondrophore (fig. 6.3) and then sequentially sampled along the hinge area (e.g., Surge, Lohmann, and Dettman, 2001; Keene, 2004; Thompson and Andrus, 2011).

Another complication is their lack of reliably rhythmic growth increments. In cross section along the chondrophore, dark and dense calcite alternates with light and chalky calcite in what appear to be growth increments. Surge, Lohmann, and Dettman (2001) found no regular seasonal pattern to increments in an estuary on the Gulf coast of Florida. Based on a sample of oyster shells from Georgia, Andrus and Crowe (2000) argued that while most increments seen in cross section were related to seasonal extremes, bands were also associated with nonseasonal events. Kirby, Soniat, and Spero (1998) found that ligamental increments were seasonal in Mississippi and Chesapeake Bay samples. Other studies in the Chesapeake Bay area have also shown regular banding (e.g., Kent, 1992; Herbert and Steponaitis, 1998). It may be that there are regional differences in growth patterns. Further studies across a broad geographic range are needed to clarify this discrepancy. As such, it is difficult to confidently estimate age and growth rate prior to sequential isotope sampling, thus limiting estimates of time-averaging and sampling resolution.

This sampling difficulty in turn may contribute in part to nonsinusoidal δ18O profiles, sometimes described as “saw-tooth” in pattern. In Andrus and Crowe (2000) these patterns were likely exaggerated by the laser sampling method whereby a single pit was ablated into each increment, leaving significant spaces of unanalyzed shell in between adjacent pits, thus increasing the likelihood of signal aliasing and the appearance of sudden variation in δ18O. Likewise, the laser method and the microenvironments at that collection site likely contributed to wider amplitudes of seasonal oscillations and more variable absolute values due to comparatively poor analytical precision and standardization. This method has since been abandoned, yet these saw-tooth patterns and variability between profiles are still seen even in finely micromilled samples analyzed with high precision (see Surge, Lohmann, and Dettman, 2001, Keene 2002; Harding et al. 2010; Thompson and Andrus, 2011). There may be several related explanations for this.

Periods of growth cessation are noted in oysters (e.g.,Kirby, Soniat, and Spero, 1998; Surge, Lohmann, and Dettman, 2001), and even short gaps may lead to abrupt changes in δ18O values if temperature and δ18O[water] change rapidly. Also, unlike most other taxa discussed here, oysters are completely sessile, epibenthic, and frequently found in intertidal zones. This means that oysters are not insulated by any sediment, have no means of avoiding temperature and salinity extremes other than closure, and may be exposed to diurnal and tidal temperature extremes that create abrupt changes in δ18O and frequent brief growth cessations. Furthermore, oysters cluster and create growing beds in ways that may promote the formation of changeable microenvironments.

The net result of these issues in terms of SOC estimates is that nonsinusoidal δ18O profiles may be commonly seen and be difficult or impossible to interpret. As a result, a comparatively high percentage of analyzed shells may not yield trustworthy data, thus adding uncertainty, cost, and time to the overall site analysis (e.g., Thompson and Andrus, 2011). It may also lead to decreased overall accuracy in SOC estimates.

In summary, even though several modern studies exist and midden oysters are already in use as SOC proxies, more baseline data are needed to better understand many key aspects of oyster growth and geochemistry. Such additional work is warranted because oysters are the dominant taxon in middens in the region and cover a wide range of habitats. The research presented in this volume by Cannarozzi (chap. 10) represents an important contribution to this progress and adds detail and new data to the description given here.

Fig. 6.3. Bisected oyster hinge in reflected light showing irregular alternating dense gray and chalky white banding.

Quahog, or Hard Clam (Mercenaria spp.)

Quahogs, or hard clams (Mercenaria mercenaria, M. campechiensis, and hybrids [B in fig. 6.1]), are the most studied of all midden molluscs in the southeastern United States with respect to oxygen isotopes and growth increments. Modern baseline incremental oxygen isotope analyses in hard clams were pioneered by Jones, Arthur, and Allard (1989) and Jones and Quitmyer (1996). Other modern baseline studies followed, including Elliot et al. (2003), Walker and Surge (2006), Surge and Walker (2006), and Andrus and Crowe (2008). Comparisons of isotope data to visual growth band analysis and modern control collections showed that, unlike some other taxa in the region, quahog growth increments form with good seasonal regularity (fig. 6.4) and can be used to assess SOC (Clark, 1979; Quitmyer, Hale, and Jones, 1985, 1997; Arnold et al., 1991; Jones and Quitmyer, 1996; Andrus and Crowe, 2008; O’Brien and Thomas, 2008; Parsons, 2008; Russo and Saunders, 2008; Thompson and Andrus, 2011; Quitmyer and Jones, chap. 7; and Jones, Quitmyer, and DePratter, chap. 8 in this volume).The two species and their hybrids are difficult to differentiate using only shell morphology; however, they can be safely treated as identical in terms of their δ18O records according to Surge et al. (2008), who made detailed comparisons of each and found no differences that would complicate their use as SOC proxies.

These clams are arguably the best and most reliable sources of sclerochronological SOC data in the region. This is due to their well-studied, regular growth patterns, temperature-dependent oxygen isotope fractionation, large size that permits easy sampling, good preservation, abundance in many middens in the region, and wide environmental tolerance. The principal limitations of these clams are that they are less abundant than oysters in archaeological sites in the region, and that they do not range into brackish and freshwater environments. Geriatric individuals may also present challenges in that banding at the shell margin is very thin and may not permit adequate sampling density to resolve seasonal shifts in δ18O (e.g., Andrus and Crowe, 2008; Parsons, 2008).

δ18O data can be used to augment incremental (structural) SOC methods (Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2008; Jones, Quitmyer, and DePratter, chap. 8, this volume) in that latitudinal (Jones and Quitmyer, 1996) and temporal (Henry and Cerratto, 2007) variation in increment precipitation has been noted. δ18O profiles compared to increments in midden clams can assess the stability of growth patterns through time and space. Thus, large numbers of shells can be visually analyzed cheaply and quickly with a few complementary isotope profiles to build confidence in the method. Application of this general approach is growing (e.g., Andrus and Crowe, 2008; O’Brien and Thomas, 2008; Thompson and Andrus, 2011) and will hopefully expand over time. Quitmyer and Jones (chap. 7) and Jones, Quitmyer, and DePratter (chap. 8, this volume) expand on these baseline data and provide more detail on the analysis of clam shells.

Fig. 6.4. Bisected quahog valve in reflected light showing regular alternating light and dark bands.

Coquina Clam (Donax variabilis)

Coquinas are not as common in most middens as oysters and quahogs but are very abundant in some archaeological sites (e.g., Quitmyer, Jones, and Andrus, 2005), typically in sites near the clam’s littoral habitat. These are small clams (C in fig. 6.1) that inhabit the surf zones of open beaches, living by burrowing in the sand and riding waves in and out with the tides. This habitat drew the attention of researchers because δ18O[water] in beach environments is typically far more stable than the habitats of other midden molluscs (Jones, Quitmyer, and Andrus, 2004). Three papers have been published on modern and archaeological coquinas (Jones, Quitmyer, and Andrus, 2004, 2005; Quitmyer, Jones, and Andrus, 2005). These papers took advantage of the stable δ18O[water] to reconstruct past sea surface temperatures (Jones, Quitmyer, and Andrus, 2004, 2005). SOC estimates have also been made using these clams (Quitmyer, Jones, and Andrus, 2005; Price, 2008).

The small size of these clams (often 1–2 cm along the longest axis) presents some challenges in sampling. Micromilling an intact valve from the outer surface is the method most often used (Jones, Quitmyer, and Andrus, 2004, 2005; Quitmyer, Jones, and Andrus, 2005; Etayo-Cadavid, 2010) and this fine-scale sampling can result in submonthly resolution. The resulting δ18O profiles generally produce smooth sinusoidal curves amenable to seasonal interpretation. In many respects δ18O profiles in these clams represent ideal SOC proxies and useful coastal marine paleoclimate proxies. The principal limitation appears to be their comparative rarity in sites in the region and their restricted habitat. Additional research into the periodicity of increments, shell structure, and environmental tolerances may improve this proxy.

Bay Scallop (Argopecten irradians)

Scallops (D in fig. 6.1) are not common in all ecosystems across this region; thus their appearance in middens is somewhat localized (Russo and Quitmyer, 1996, 2008; Withers and Hubner, 2009). Argopecten irradians concentricus is the dominant subspecies found in the southeastern U.S. Atlantic and Gulf coasts (MacKenzie, 2008). This scallop is extensively well studied with respect to basic biology (see MacKenzie, 2008, for a recent review), but no published analysis of oxygen isotope shell data exists. Archaeological analyses of these scallops have focused on SOC estimates using shell length measurements (Russo and Quitmyer, 1996, 2008) and changes in shell morphology (Marelli and Arnold, 2001).

Examination of the shell structure and mineralogy suggests that there may be several challenges to overcome when measuring δ18O profiles in these scallops. For example, the shell is composed of two calcite layers separated by an aragonite layer. Such a configuration makes micromilling single-mineral samples difficult. Prior knowledge of sample mineralogy is necessary to generate and interpret δ18O data from bimineralic shells because aragonite and calcite have differing phosphoric acid fraction factors (Kim, Mucci, and Taylor, 2007) and potentially different original isotopic enrichments (Cusack et al., 2008). Undetected mixing of mineral samples could alter the seasonal δ18O profile and complicate assignment of SOC.

Additional alteration of scallop δ18O profiles can be due to seasonally episodic growth. Significant winter mortality occurs in this species in at least part of its range after the first year of growth (Russo and Quitmyer, 1996, 2008). This suggests that sublethal exposure to seasonal temperature extremes may lead to diminished or paused shell growth and result in truncation of seasonal δ18O oscillations. Although these growth and structural issues need to be addressed, sequential isotopic analysis in morphologically similar scallops has been successful in measuring seasonal environmental variation (e.g., Jones et al., 2007).

Ribbed Mussel (Geukensia demissa)

Although ribbed mussels (E in fig. 6.1) are found in southeastern U.S. shell middens (e.g., Keene, 2002; Quitmyer and Reitz, 2006; Parsons, 2008) and are abundant in regional salt marshes, no sequential oxygen isotope data have been published for this species. However, fairly extensive geochemical, mineralogical, and microstructural analysis has been performed on closely related species from similar coastal environments (Jones and Kennett, 1999; Vander Putten, 2000; Gillikin et al., 2006; Wanamaker et al., 2006, 2007; Cusack et al., 2008; Jones et al., 2008; Ford et al., 2010; Jones, 2010). One study (Lécuyer, Reynard, and Martineau, 2004) analyzed bulk (no time series data) δ18O samples from Caribbean ribbed mussels and noted temperature-dependent oxygen isotope distributions. Collectively, these studies demonstrate that making isotopic estimates of SOC is likely possible, but as with the bay scallops, there are several potential problems that need to be addressed before these mussels can be analyzed with confidence.

First among these concerns is a need to have a detailed understanding of the shell microstructure and mineralogy. Lécuyer, Reynard, and Martineau (2004) performed Raman analyses on one shell and detected only aragonite; however, some mussels like Mytilus edulis (Vander Putten et al., 2000) and Choromytilus chorus (Jones, 2010) also contain calcite. More detailed mineralogical and microstructural analysis is required because δ18O data from bimineralic mussels presents a similar situation as described above for bay scallops. Furthermore, in some other mussels, different textures and crystal habits of the same mineral are present across shell layers and contain different isotopic values (Cusack et al., 2008; Jones, 2010).

Shell growth rate in this species is not uniform throughout the year in the southeastern United States (Borrero and Hilbish, 1988). Growth cessations and significant changes in growth rate over ontogeny have been seen to impact δ18O profiles in related taxa (e.g., Jones, 2010). Studies of modern populations of ribbed mussels are needed to fully assess whether growth rate impacts their utility as SOC indicators. Seasonal δ18O profiles may also be impacted by damage to the fragile valves during life (Hillard and Walters, 2009).

If absolute temperature reconstructions are desired, it may also be necessary to develop a species-specific isotope temperature equation. Other mussels such as Mytilus edulis (Wanamaker et al., 2006, 2007) and Mytilus californiensis (Ford et al., 2010) have slightly different slopes and significantly different y-intercepts to their respective isotope/temperature relationships. The only published δ18O data from this species (Lécuyer, Reynard, and Martineau, 2004) lack adequate environmental monitoring to assess which, if any, published equation is suitable.

The biggest obstacle to the use of ribbed mussels for SOC analysis may be taphonomy. Compared to oysters and quahogs, their shells are quite thin and fragile. They are typically excavated in fragments that may be too small to generate a seasonal sinusoidal curve with which to compare the edge values. Because they live in similar habitats to the oyster and thus experience highly variable δ18O[water], such complete sinusoids are necessary to measure SOC.

Stout Razor Clam (Tagelus plebeius)

Razor clams (F in fig. 6.1) are often present in middens in the Southeast (e.g., Pearson, 1977; Keene, 2002; Quitmyer and Reitz, 2006; Parsons, 2008), but little SOC research has been conducted on them. No published studies exist regarding seasonal growth in their shells or oxygen isotope distributions. These large, robust clam valves preserve comparatively well in middens and would be technically straightforward to sample sequentially. Morphologically similar razor clams have been analyzed for sequential isotope data in Peruvian and Chilean middens (e.g., Carré et al., 2005, 2009; Jones et al., 2010b). These South American shells produced regular, seasonal sinusoidal patterns, with abrupt summer shifts in shell δ18O values indicating subseasonal warm temperature growth cessations (Carré et al., 2005; Jones et al., 2010b). The Pacific coast of South America has a far narrower range in seasonal water temperatures and very little variation in δ18O[water] as compared to the southeastern United States; therefore, direct analysis of modern T. plebeius is required to assess the seasonality of shell growth.

Research on modern populations in South Carolina by Holland and Dean (1977) suggest that these razor clams contain annual growth bands and grow most rapidly in summer and fall with variation between habitats and tidal zones. Lomovaskya, Gutiérrez, and Iribarnea (2005) note that specimens of T. plebeius commonly display evidence of shell damage and repair around the valve edge (>70% in their samples). Similar to periods of growth cessation or diminishment, this may have significant impact on the shape of the seasonal δ18O profiles and should be assessed with controlled modern studies.

Marsh Clam (Rangia cuneata and Polymesoda caroliniana)

Unlike the other taxa thus far discussed, marsh clams live in brackish to nearly fresh water environments and thus may provide insight into subsistence activities and seasonal timing outside the immediate coast. Rangia cuneata (G in fig. 6.1) is the dominant marsh clam in habitats and middens along the Gulf of Mexico coast, and Polymesoda caroliniana (H in fig. 6.1) is more abundant on the Atlantic coast. While R. cuneata is frequently the most abundant species in Gulf middens (e.g., Aten, 1981; Carlson, 1987), P. caroliniana is less often found in either coast.

There are three published δ18O studies of R. cuneata (Lécuyer, Reynard, and Martineau, 2004; Andrus and Rich, 2008; Cobb, Andrus, and Etayo-Cadavid, 2009); however, they do not focus directly on measuring SOC; rather, they examine basic sclerochronological concerns such as isotope fractionation and growth rates and patterns. R. cuneata precipitates aragonite shells in or near oxygen isotope equilibrium, which supports its use for SOC determinations (Lécuyer, Reynard, and Martineau, 2004; Andrus and Rich, 2008). However, it appears that these shells are prone to frequent growth cessations that are neither rhythmic nor consistent within a population (Cobb, Andrus, and Etayo-Cadavid, 2009). These growth cessations are often visible in the shell structure and are described as partly seasonal in some locations (Fairbanks, 1963; Carlson, 1987). This irregular growth may be a result of the highly variable environments of upper estuaries where temperature, salinity, turbidity, and other factors rapidly and unpredictably change. These growth cessations may result in nonsinusoidal δ18O profiles that complicate SOC assessments. However, δ18O profiles thus far analyzed (fig. 6.5) contain predictable sinusoidal oscillations. The irregular growth breaks likely contribute to subseasonal abrupt changes in δ18O but may not obscure the overall seasonal trends.

In contrast, no published δ18O studied of P. caroliniana exist, but similar growth habit and environments suggest that it may share general sclerochronological properties with R. cuneata and other closely related clams. For example, Polymesoda radiata was measured for shell δ18O to assess seasonality of rainfall and SOC in midden samples from Pacific Mexico (Kennett and Voorhies, 1995, 1996).

While more research may be required before confident SOC estimates can be made from upper estuarine species such as these, the results may warrant the effort. Currently, sclerochronological analysis in the southeastern United States focuses on marine and lower estuarine species, thus human subsistence activities in fresh and brackish water habitats are less well understood. This means archaeologists may be blind to a significant portion of a seasonal subsistence round or resource area.

Fig. 6.5. Sequential δ18O data from R cuneata valve (0608.2) collected from Chocolatta Bay where it enters Mobile Bay, AL (30°40′36″S and 87°58′21″W) collected on June 8, 2006. Ontogeny runs left to right, with sample from valve edge on right of plot. Dashed lines divide the seasonal range in δ18O into equal thirds. δ18O analytical precision is finer than ± 0.1‰ (based on analysis of NBS-19 average across all runs). Following the methods outlined in figure 6.2, the SOC estimate is spring.

Freshwater Mussels (Unionidae)

Moving further up the estuaries of the region, marine and brackish species give way to freshwater mussels (K in fig. 6.1). These clams thus become more common in archaeological sites deeper into the interior coastal plain. However, there has been little research into δ18O sclerochronology in these taxa. Carroll, Romanek, and Paddock (2006) measured oxygen and hydrogen isotope variation in Savannah River watershed mussels and Peacock and Seltzer (2008) examined the elemental geochemistry of shell fragments in ceramics as a means to examine paleoenvironmental conditions, but no work focused on SOC measurements has been done. δ18O analysis has been conducted in some western U.S. and European unionids (e.g., Dettman, Reische, and Lohmann, 1999; Goewert et al., 2007; Versteegh et al., 2009, 2010). These studies suggest that while unionid δ18O values reflect seasonal environmental changes, there are sometimes significant periods in which shell growth stops. Long cessations may limit these mussels’ utility as SOC proxies, but further baseline studies are needed before this can be concluded.

Other challenges may impede the use of these species as well. These shells are very fragile and are often deposited in acidic soils that contribute to recrystallization of their aragonite. Although recrystallization is relatively easy to detect, other taphonomic concerns create additional problems. In particular, these shells tend to fragment and spall along growth increments, and inner layers of the shells foliate cleanly, leaving what appears to be a pristine shell that in fact is missing its innermost layers. This property is common enough that it has been exploited to aid in ontogenetic sampling of mussel shells (Nelson, 1964; Sterrett and Sayville, 1974). Such breakage may occur during site formation or excavation, and if undetected may lead to erroneous SOC estimates (fig. 6.6).

Species-specific issues may exist as well. Some unionids are quite long-lived and grow slowly late in life with very thin increments that make sequential sampling at seasonal resolution difficult (e.g., Schöne et al., 2004; Versteegh, 2009). However, sampling resolution adequate to assess SOC has been achieved in some freshwater mussels (Goewert et al., 2007). Even if species-specific baseline studies are conducted to address concerns of differential growth rate and cessation, species identification is sometimes difficult in archaeological mussel shells. This is especially true of fragmentary specimens, which might be expected in middens or those that have eroded or broken hinge areas.

Habitat-specific concerns exist as well. δ18O[water] values can vary according to a number of factors that may complicate interpretation of mussel δ18O profiles. For example, small, shaded, spring-fed streams may have little differences in δ18O[water] from season to season, but slower, shallow, and exposed bodies of water subject to seasonal evaporation may have wide variation in δ18O[water].

In summary, freshwater mussels represent one of the most complex challenges in terms of developing new taxa for isotopic SOC studies. However, the lack of alternative taxa in interior sites may warrant the effort and provide insight into links between coastal and inland subsistence strategies.

Fig. 6.6. Archaeological Unionidae clam valve. The preservation of this specimen is typical of sites in the region. Note the spalling occurring on the right. Entire shell layers have been noted to foliate along growth increments, potentially leaving what appears to be an intact valve. Such taphonomic issues could lead to erroneous season-of-capture estimates.

Gastropods

There are no published oxygen isotope studies of archaeological southeastern U.S. gastropods. Some relatively common midden gastropods include the whelks Busycon carica (J in fig. 6.1), Busycon sinistrum, Busycon spiratus, Busycotypus canaliclatum, and the periwinkle, Littorina irrorata (I in fig. 6.1). Gastropods have been analyzed for oxygen isotopes from other archaeological contexts in other regions (e.g., Mannino, Spiro, and Thomas, 2003; Mannino et al., 2007; Colonese et al., 2009), and presumably the southeastern U.S. species would be similar in at least some respects.

Busycon whelks are particularly important in southeastern archaeology as they were modified and traded as utilitarian objects and gorgets, and as such their geochemistry has been used to assess provenance (Claassen and Sigmann, 1993). While these other uses may complicate their interpretation as subsistence remains in middens, it magnifies the importance of their potential as seasonality indicators in that insight into trade and tool procurement practices may be possible. Unfortunately, little baseline data exist concerning the specifics of whelk isotope geochemistry or sclerochronology.

The work that has been done underlines the importance of baseline studies. For example, mark and recapture data suggest that shell growth rates are highly variable, that some shells may not grow for extended periods, and that shell abrasion is common along the aperture edge (e.g., Eversole, Anderson, and Isely, 2008). Growth rates may also vary between sexes (Power, Sellers, and Walker, 2009), and habitat (Walker et al., 2008). Unlike most bivalves, whelks in this study area migrate, often with different patterns between species (e.g., Walker et al., 2008). These factors can complicate the interpretation of seasonal oscillations in δ18O by altering both the seawater temperature and the δ18O[water] experienced by the snails. Furthermore, other gastropods, notably the queen conch (Strombus gigas) are offset from oxygen isotope equilibrium (Wefer and Killingley, 1980). Such offsets do not preclude SOC estimates, but suggest the need for species-specific baseline analyses.

Periwinkles (Littorina irrorata) are common at some sites (e.g., Quitmyer and Reitz, 2006), but no isotope sclerochronology has been performed on this species. However, the calcite shells of the closely related Littorina littorea have been studied in both modern and archaeological contexts, and the resultant δ18O records show promise because the periwinkle oxygen isotope fractionation is temperature dependent and at least some populations record the full seasonal range of temperatures (Andreasson, Schmitz, and Jönsson, 1999; Burman and Schmitz, 2005; Burman and Påsse, 2008). Key questions remain concerning the continuity of growth, shell margin damage, and other issues that need to be addressed with local modern baseline data.

CONCLUSIONS

This review illustrates some of the reasons why the expansion of isotope sclerochronology in midden analysis is slow and expensive. Each potentially useful species requires fundamental baseline studies before archaeological application can be considered reliable. Even some of the most extensively studied molluscs such as quahogs and oysters still demand further research. Progress toward expanding the range of SOC indicator species will likely occur piecemeal, with different taxa being studied according to relative abundance in key regions and their utility in answering archaeological questions.

Currently, oysters, quahogs, and coquina clams have been studied adequately enough to allow at least some application of SOC analyses in the southeastern United States. Rangia clams will likely soon join this list because new studies are underway. An effective means to expand the number of SOC indicator species applicable to the southeastern United States would be to target those organisms having close relatives that have been used in other regions. For example, scallops, razor clams, and mussels from other parts of the world have been successfully utilized in archaeological research. Building on these preexisting studies may partially limit the extent of needed baseline research on local species. To my mind, the most important knowledge gap to address is in freshwater habitats. Unfortunately, molluscs in these environments may also present some of the greatest analytical challenges.

Finally, I hope this review highlights the need to conduct comprehensive analyses of human dietary remains. While isotope sclerochronology may be too expensive and specialized for many archaeological purposes, simple and low-cost approaches may yield similar conclusions. Mollusc shells need not be relegated to the back-dirt pile but should be retained, identified, and at least roughly quantified. These data can be greatly strengthened when integrated into vertebrate and botanical analyses. By having a large repertoire of seasonality indicators, with different biases and sources of error, we may more confidently reconstruct not only season of exploitation, but also more complex questions of occupation patterns, site formation processes, and overall subsistence strategies. This integrated approach has yielded broadly significant results on St. Catherines Island over the past decades and may serve as a template for others.

CHAPTER 7: Annual Incremental Shell Growth Patterns in Hard Clams (Mercenaria spp.) from St. Catherines Island, Georgia: A Record of Seasonal and Anthropogenic Impact on Zooarchaeological Resources

Irvy R. Quitmyer and Douglas S. Jones

Sclerochronology is the study of physical and chemical variations in the accretionary hard tissues of organisms, and the temporal context in which they formed. Sclerochronology focuses primarily upon growth patterns reflecting annual, monthly, fortnightly, tidal, daily, and sub-daily increments of time entrained by a host of environmental and astronomical pacemakers. Familiar examples include daily banding in reef coral skeletons or annual growth rings in mollusc shells. Sclerochronology is analogous to dendrochronology, the study of annual rings in trees, and equally seeks to deduce organismal life history traits as well as to reconstruct records of environmental and climatic change through space and time. —1st International Sclerochronology Conference, 2007

Historically it has been recognized that a diverse number of plant and animal taxa form repeating growth structures in their skeletons (Rhoads and Pannella, 1970; Rhoads and Lutz, 1980; Jones and Gould, 1999). Many times these structures represent physiological responses to environmental stimuli that can be regarded as biorecordings of the life and times of an organism (Jones and Quitmyer, 1996). It was not until the last half of the 20th century that scientists realized the potential of asking and answering natural history questions through the study of these structures (Wells, 1963; Buddemeier, Maragos, and Knutson, 1974; Hudson et al., 1976). In concert with natural historians, zooarchaeologists seized on sclerochronology as a tool to address one of the fundamental questions posed by archaeologists—during which seasons did people occupy a given archaeological site (Weide, 1969; Coutts, 1970, 1975; Coutts and Higham, 1971; Ham and Irvine, 1975; Koike, 1975)? The answer to such a question helps to define settlement patterns, and subsistence strategies. Such definitions expand our understanding of cultural complexity found in the archaeological record.

There is an emerging body of zooarchaeological inquiry that is examining the intensity of resource use, resource management strategies, and natural and anthropogenic changes in the environment. Methods grounded in sclerochronology are helping to explore whether prehistoric peoples were good ecologists, conservationists, both, or neither (Quitmyer, Hale, and Jones, 1985; Thomas, 1987; Quitmyer and Jones, 2000; Marcello and Thomas, 2002; Quitmyer, 2003; Peacock, Haag, and Warren, 2004; Hames 2007; Rick and Erlandson, 2008; Erlandson et al., 2008; Szabó and Quitmyer, 2008)? The literature also identifies instances where there are changes in zooarchaeological assemblages that are not anthropogenic in origin, but related to a changing environment (e.g., Bailey and Craighead, 2003).

In southeastern North America, sclerochronology of hard clams (Mercenaria spp.) as a zooarchaeological indicator of season of resource harvest first emerged from archaeological research conducted on St. Catherines Island, Georgia (Clark, 1976a, 1976b; O’Brien and Thomas, 2008). These early researchers showed that hard clams are suitable taxa for such work and are ubiquitous in the shell middens. Sclerochronology of hard clams has become an integral part of St. Catherines Island archaeological research and has influenced zooarchaeological research throughout southeastern North America (Claassen, 1982; Quitmyer, Hale, and Jones, 1985; Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2008).

This research represents the third year of a five-year study of modern incremental shell growth in St. Catherines Island hard clams (Mercenaria mercenaria) that was undertaken by the authors in collaboration with David Hurst Thomas, American Museum of Natural History. Our first goal is to establish longitudinal growth frequency profiles of incremental shell growth among living populations of St. Catherine Island hard clams. We seek to assemble a robust sample that is systematically collected to document the annual periodicity of incremental shell formation. These data augment earlier research by O’Brien and Thomas (2008) that started during the mid to late 1970s and more recent research conducted by Andrus and Crowe (2008). We apply the modern model of incremental shell growth to zooarchaeological hard clams excavated from the Late Archaic at St. Catherines Shell Ring (ca. 4500 b.p.), and McQueen Shell Ring (4450 b.p.) (general levels and “floor” feature). We note that the McQueen “floor” archaeological feature is constructed of a sand base covered with a modest number of hard clam shells (Thomas, personal commun.). Relative to the general levels of the two St. Catherines Island Archaic period sites, the “floor” feature represents a distinct period in time at McQueen. We also include previously published data from nearby Cannon’s Point Shell Ring (ca. 4500 b.p.), St. Simons Island, GA (Marrinan, 1975; Quitmyer, Hale, and Jones, 1985).

Our second research objective is to examine the population dynamics of the three Archaic period assemblages. We apply commonly used fisheries statistics that help to evaluate and manage living hard clam populations by quantifying their size classes, survivorship, and ontogenetic age (Fegley, 2001). In so doing we are able to assess relative harvesting pressure during the Archaic period on St. Catherines Island and at Cannon’s Point.

METHODS

Modern Hard Clams

Hard clams form alternating white and gray (or purple) shell growth increments that may be seen in cross sections of their shells using direct (fig. 7.1A) or transmitted light (fig. 7.1B). Backlit radial thin sections of the shells show that the white increment is opaque while the gray (or purple) increment is translucent, allowing the transmission of light (fig. 7.1B). The two increments represent distinct differences in the shell microstructures that are known to be periodic and associated with physiological responses to environmental changes in the annual cycle (Clark, 1976a; Quitmyer, Jones, and Arnold, 1997; Fritz, 2001: 60–61). We use the terms translucent and opaque to characterize the shell growth increments in this chapter (figs. 7.1B and 7.2).

We follow the methods of Quitmyer, Jones, and Arnold (1997) to establish a chronology of annual incremental shell formation in living St. Catherines Island hard clams. Approximately 40 living hard clams were collected monthly for one year (2007–2008) from a shallow tidal creek in King New Ground that flows into McQueen Creek. The specimens were collected by hand from sandy mud and shell substrate around the base of oyster bars. This represents typical hard clam habitat as reported in the literature (Walker and Tenore, 1984; Fegley, 2001). The specimens were transported to the St. Catherines Island compound where they were quickly frozen in a commercial grade freezer. Following transport back to the Florida Museum of Natural History, the specimens were thawed and eviscerated. The valves were washed, dried, numbered, and stored for later analysis.

Historical sea surface temperature (SST) and salinity (PSU) data were obtained from the National Estuarine Research Reserve System monitoring station (SAQG1) at nearby Sapelo Island, Georgia. These data represent a close approximation of estuarine SST and salinity for the region during 2008.

The size and age data provide significant information about the natural history of hard clams and the interpretation of their use by Native Americans (see Jones, Quitmyer, and DePratter, chap. 8, this volume). The anterior to posterior length of the right valve of each specimen was measured using digital calipers attached to a personal computer (Jones, Quitmyer, and DePratter, chap. 8).

A radial cross section of the right valve, from the umbo to the ventral margin, was facilitated with a water-cooled lapidary saw equipped with a Mark V alumina oxide blade (Quitmyer, Jones, and Arnold, 1997). The blade produced a polished surface where the incremental growth structures could be evaluated with the unaided eye and/or microscopically (10–20×) with transmitted light (Rhoads and Lutz, 1980; Quitmyer, Hale, and Jones, 1985; Ropes, 1987; Jones et al., 1990: 217; Quitmyer and Jones, 1992).

It is generally agreed that hard clams living in the southeastern part of their range form a couplet of opaque and translucent shell growth increments each year (fig. 7.2; Jones and Quitmyer, 1996; Quitmyer, Jones, and Arnold, 1997; Fritz, 2001; Andrus and Crowe, 2008). A count of the paired increments provides a direct method of assessing the longevity of hard clam assemblages (Jones and Quitmyer, 1996; Fegley, 2001; Jones, Quitmyer, and DePratter, chap. 8, this volume).

At a finer seasonal scale, the size of opaque or translucent shell increments at the growing margin of the shell may be used to estimate the season in which a hard clam was harvested (Jones and Quitmyer, 1996; Quitmyer, Jones, and Arnold, 1997). A six-part subdivision of the annual shell growth cycle was used to establish a seasonal growth model in order to resolve the season of harvest of the zooarchaeological hard clams (fig. 7.3). The formation of the translucent growth increment was divided into three stages or phases: (a) translucent 1 (T1)—translucent increment just starting to form; (b) translucent 2 (T2)—translucent increment approximately one-half the size of the previous year’s translucent increment; (c) translucent 3 (T3)—translucent increment equal to or greater than the previous translucent increment. The formation of the opaque growth increment was similarly divided into three growth phases: (a) opaque 1 (O1)—opaque increment just starting to form; (b) opaque 2 (O2)—opaque increment approximately one-half the size of the previous year’s opaque increment; (c) opaque 3 (O3)—increment nearly completed, almost equal in size to the previous year’s opaque increment. It should be noted that early in ontogeny the T3 and O3 growth phases are relatively more common. With increasing age it becomes increasingly less likely that T3 and O3 phases would exceed those of the previous year. Nonetheless, this provides a temporal profile of incremental shell growth in the hard clam population.

The frequency of individuals in each of the various phases of incremental shell growth was calculated for each month and each season, to document an annual pattern that is presented as a histogram for each of the four seasons. This simple, straightforward technique accurately characterizes seasonal incremental shell growth (Claassen, 1990; Quitmyer, Jones, and Arnold, 1997).

The zooarchaeological samples were prepared and analyzed in accordance with the methods outlined for the modern comparative collection of hard clams. The St. Catherines Island modern analog of incremental shell growth was used to evaluate the zooarchaeological assemblages. We note that zooarchaeological season of harvest does not rest on the shell growth of a single hard clam, but on a population approach where all individuals contribute to a seasonal pattern of incremental shell growth. The growth frequency profiles constructed from our 2007–2008 longitudinal study are used to evaluate zooarchaeological hard clams excavated from St. Catherines Shell Ring, McQueen Shell Ring (general levels and “floor” feature), and Cannon’s Point Shell Ring, St. Simons Island, Georgia.

Fig. 7.1. Radial cross section of a hard clam (Mercenaria campechiensis) to expose its growth increments (A) and a backlit thin section (B) showing the alternating opaque and translucent shell growth increments.

Fig. 7.2. The location of the translucent and opaque shell growth structures showing a count of the ontogenetic age (years) of a specimen.

Fig. 7.3. Six-part division of translucent and opaque annual shell growth increments in hard clam (Mercenaria spp.) shells.

RESULTS

Modern Cycle of Incremental Shell Growth

Our results are based on a numerically robust sample of a population of modern St. Catherines Island hard clams. Because the various phases of individual incremental shell formation may be observed in most months of the year, an individual’s shell growth does not describe the overall pattern of growth in a modern or zooarchaeological population. It is tempting to use these proxy data to interpret the zooarchaeological shells at monthly or subseasonal levels (e.g., late spring); however, hard clam populations are responsive to various environmental stimuli that are variable across space and time. Such is the nature of most biological populations.

Figure 7.4 presents a sclerochronological comparison of opaque and translucent shell growth through an annual cycle. This is simply meant to show the monthly progression of the two shell growth increments in the population. Translucent shell growth is present in at least some of the individuals during every month; it becomes the dominant increment during the summer and fall seasons. Opaque shell growth is most prevalent during the winter and extends into the spring. This pattern correlates with previous studies in southeastern North America, such as Kings Bay, Georgia (fig. 7.4; Quitmyer, Jones, and Arnold, 1997; Fritz, 2001; Henry and Cerrato, 2007) and Litchfield Beach, South Carolina (Jones, Quitmyer, and DePratter, chap. 8, this volume). Previous researchers have reported that the sequential formation of opaque and translucent shell is a physiological response to seasonal changes in temperature or factors related to temperature (Ansell, 1968). Temperatures ranging between 15° C and 20° C are regarded as optimal: the range in which the animal attains maximum growth rates (Fegley, 2001). Near the thermal maximum and minimum, 31° C and 7° C, respectively, growth abates, then stops. A similar relationship between temperature and shell growth exists in the St. Catherines population (fig. 7.4). Opaque shell growth is most prevalent when SST is at the animal’s thermal optimum during the late winter and spring (fig. 7.4). As SST reaches the thermal maximum (31° C) for the organism, translucent shell growth dominates the seasonal profile. In fact, Quitmyer, Jones, and Arnold (1997) observed this same shell growth profile in five modern populations occurring along the Atlantic and Gulf coasts between Litchfield Beach, South Carolina, and Cedar Key, Florida (also see Andrus and Crowe, 2008).

At the seasonal scale, 34.8% of the St. Catherines Island population is forming T3 shell growth in the winter, while around 65% is in the O1 (17.4%), O2 (21.7%), and O3 (26.1%) shell growth phases (fig. 7.5). In the spring season T3 shell growth is observed in 30% of the specimens, while 70% of the individuals are forming the opaque growth increments: O1, 8.3%; O2, 31.7%; and O3, 30%. By the summer season 87% of the population has reached T3 shell growth and a similar pattern extends into the fall season. Contrary to previous studies where the six-part subdivision of seasonal growth has been used to distinguish all four seasons, only two halves of the year can be confidently identified in the St. Catherines population: winter/spring and summer/fall (fig. 7.5).

Fig. 7.4. The relationship of sea surface temperature (°C) and monthly formation of translucent and opaque growth in modern hard clams collected live from St. Catherines Island and Kings Bay.

Fig. 7.5. Seasonal growth frequency patterns of modern hard clams (Mercenaria) collected live from St. Catherines Island, 2007–2008.

Zooarchaeological Hard Clams—Season of Resource Procurement

The modern SCI six-part subdivision of incremental shell growth (fig. 7.5) is used as a model to evaluate the zooarchaeological season of hard clam collection from St. Catherines Shell Ring (N = 117), McQueen Shell Ring (general levels N = 68; “floor” feature, N = 54), and Cannon’s Point Shell Ring (N = 35) (fig. 7.6). The data from the four sites show that the majority of the zooarchaeological specimens were forming opaque shell growth (figs. 7.5 and 7.6). The best fit with the modern growth frequency profiles suggests the zooarchaeological hard clams were harvested in late winter and spring (fig. 7.5). Relative to St. Catherines and McQueen, the greater frequency of the T3 shell growth phase in the Cannon’s Point assemblage suggests a harvest period that was more active during the winter, albeit still in the winter/spring seasons. This is the time when the modern specimens have transitioned out of T3 shell growth phase and undergo rapid opaque shell formation (fig. 7.4). It is also the time when the population begins their major spawning event.

Fig. 7.6. Growth frequency profiles of zooarchaeological hard clams collected from St. Catherines Island and Cannon’s Point, representing the Archaic period.

Population Dynamics—Modern Ontogenetic Age and Survivorship

As we note above, a combination of one opaque and one translucent or opaque increment represents one year of life (fig. 7.2). Thus, a count of the translucent growth increments yields an accurate account of the ontogenetic age (years) of each individual. The question arises, why go to the trouble of sectioning and counting the growth increments to assess hard clam population dynamics? Why not use size as a proxy for age and simply measure each specimen? Figure 7.7 presents a plot of shell length, anterior to posterior (mm), against ontogenetic age (years) for the modern St. Catherines and zooarchaeological McQueen hard clams. As we have observed elsewhere (Jones, Quitmyer, and DePratter, chap. 8, this volume) there is considerable overlap in size versus age relationships in hard clams (see also Walker and Tenore, 1984; Fegley, 2001). For example, the shell lengths of a six-year-old modern cohort overlap those of 12-year-old clams (fig. 7.7). Further, a 30-year-old clam can be the same size as a three-year-old clam. Researchers have found that the growth of same-aged individuals may be affected by genetic and environmental variables (Fegley, 2001). Environmental variables may include water quality, substrate type, and predator-prey relationships. At best, size is a coarse proxy for age and direct age-determined models provide greater confidence in assessing hard clam population dynamics (fig 7.7; Fegley, 2001). Because of the overlap in size and age observed in the samples, the use of population age dynamics dispenses with the possibility of modern or zooarchaeological size-specific collection inefficiency that may occur during the course of harvesting (Haddon, 2001).

Survivorship curves are commonly used in fisheries biology to examine the health of animal populations (Fegley, 2001). The percentage of hard clams surviving each year for living populations collected from Kings Bay, and St. Catherines Island, Georgia, serve as an example (fig. 7.8; table 7.1). Like many other hard clam populations living along the Georgia coast, the Kings Bay assemblage may be considered unimpacted or in equilibrium (Walker, 1989). The Kings Bay specimens were sampled (1983–1984) from a military reserve where harvesting was prohibited for over 40 years. The Kings Bay and St. Catherines Island hard clam survivorship curves show great similarity with a gradual loss of individuals with time. Between 31% and 40% of the two populations can expect to live at least 10 years. There is also great similarity in the mean ages of the St. Catherines Island (9.4 years) and Kings Bay (10.4 years) populations (fig. 7.9). In fact, a plot of the 95% confidence intervals around the means overlap and indicate that the two sample assemblages could have been derived from the same population (fig. 7.9). These data also confirm previous research showing that hard clam beds are typically dominated by older, larger individuals (Walker and Tenore, 1984).

Population Dynamics—Zooarchaeological Mean Age and Survivorship

The curves for the zooarchaeological specimens from the St. Catherines Shell Ring and McQueen Shell Ring show a dramatic loss of individuals during the first four years of life (fig. 7.8). In contrast to the two modern populations, fewer than 11% of the zooarchaeological hard clams attained 10 years of age (fig. 7.8). The mean ontogenetic ages of all three St. Catherines Island zooarchaeological samples is around three years (fig. 7.9). The 95% confidence intervals around the means all overlap, indicating that they could have been collected from the same living population (fig. 7.9). The mean age of the St. Simons shells is six years and the 95% confidence interval does not overlap with the modern or St. Catherines Island assemblages (fig. 7.9).

Fig. 7.7. A comparison of shell length (mm) to ontogenetic age (years) of modern and zooarchaeological hard clams from St. Catherines Island.

Fig. 7.8. Survivorship curves characterizing modern and zooarchaeological hard clams from St. Catherines Island, Cannon’s Point, and Kings Bay.

Fig. 7.9. Mean age (years) and 95% confidence intervals plotted for modern and zooarchaeological hard clams from St. Catherines Island, Cannon’s Point, and Kings Bay.

DISCUSSION

In the archaeological literature the term seasonality refers to questions of variability in the seasonal round of settlement behavior. Such studies are in their infancy (Russo and Quitmyer, 1996) and they are typically biologically based. As such, they require long-term field and laboratory analysis of modern taxa before the zooarchaeological record can be interpreted. Zooarchaeologists sometimes erroneously refer to these as site seasonality studies; but, seasonal site occupation and seasonal patterns of resource procurement (e.g., shellfish collection) represent two different kinds of human behavior (Deith, 1983: 423). Unless a single taxon represents all seasons of resource procurement, site seasonality cannot be confidently determined. Repeated sampling and analysis of multiple indicators of resource procurement may provide a more confident indication of seasonal or year-round site occupation (Quitmyer, Jones, and Arnold, 1997). This research is intended to extend our knowledge of the sclerochronology of the hard clam as one tool that may be used to interpret human interaction with the environment.

The application of the six-part subdivision of incremental shell growth in monthly collections of St. Catherines Island hard clams does not provide unique profiles of shell growth that can be used to identify all of the four seasons of the year (fig. 7.5). However, the modern analog provides a basis to distinguish winter/spring from summer/fall collection of zooarchaeological hard clams. When the St. Catherines Island modern profile of seasonal shell growth is applied to the zooarchaeological assemblages from St. Catherines Shell Ring, McQueen Shell Ring general levels, McQueen Shell Ring floor deposit, and from Cannon’s Point Shell Ring, a clear winter/spring pattern of hard clam harvest is evident. In fact, all four of the zooarchaeological growth frequency profiles have elevated levels of Opaque 1 growth phase (fig. 7.6) relative to the other growth phases. This represents the onset of rapid shell growth during the winter and spring seasons where water temperature approaches optimal (15° C–20° C) (Ansell, 1968). Such a pattern suggests an intensive period of harvest as opaque shell growth forms.

This winter/spring pattern of hard clam procurement is prevalent across space and time for zooarchaeological assemblages along the southeastern Atlantic coast. Nearly half of the 26 sites (48%) reported by Quitmyer, Jones, and Arnold (1997) contained hard clams that were specifically harvested during the winter/spring seasons. These represent a diverse number of archaeological cultures that date between 550 and 4500 b.p. We do not attempt to explain this long period of preferentially harvesting hard clams during the winter and spring seasons in this chapter. This is a subject for future inquiry. However, it is clear that during the Archaic period on St. Catherines Island and at Cannon’s Point, hard clams were intensively harvested during the winter and spring seasons.

Here we question how the population dynamics of the Archaic period hard clams might have been affected by intensive harvesting pressure as seen through their biology and ecology. First, we note that the modern Kings Bay population is at or very near equilibrium because that locality has been closed to harvesting for several decades. Although technically the St. Catherines population is not closed to harvest, it experiences negligible recreational clamming as a private island and as a consequence has a similar age class frequency distribution when compared to the Kings Bay assemblage. In fact, many beds throughout coastal Georgia have experienced very little harvesting and have some commonality with our two modern populations (Walker, 1989; Fegley, 2001). For these reasons our two modern populations serve as baselines when we assess the age frequency of the four zooarchaeological assemblages.

Our age-based analysis of the three St. Catherines Island zooarchaeological populations are all dominated by individuals that are between two and six years old (fig. 7.7). In contrast to our two modern baselines and previously published biological data for the Georgia coast (Fegley, 2001), the zooarchaeological hard clams are nearly devoid of specimens older than six years (fig. 7.7). In fact, specimens from the two modern baseline populations average around 10 years old while the St. Catherines Island zooarchaeological specimens are approximately three years old (fig. 7.9). The zooarchaeological survivorship curves are representative of a population where there is great mortality in early in life with very few individuals reaching full longevity (fig. 7.8; Deevey, 1947). Such a pattern is not typical of hard clam populations in southeastern North America that may be considered in equilibrium. These data suggest a population where intensive harvesting has occurred.

As we have outlined in another chapter in this volume (Jones, Quitmyer, and DePratter, chap. 8), the biology and ecology of hard clams make them susceptible to measurable harvesting pressure. In southeastern North America, most populations occur in densely circumscribed beds that are easily collected from their preferred habitats in shallow tidal creeks. These beds are usually dominated by older, larger specimens that are easily located by hand collection. Once the larger specimens are removed, the smaller individuals become more susceptible to natural predation. Intensive harvest of hard clams during their peak spawning period (spring) would have further deleterious impact on the beds.

In many cases, humans manage their subsistence resources by limiting the sizes of animals that they hunt and gather (Kraeuter and Castagna, 2001), thus leaving mature and productive individuals to replenish the population. Size-class selection does not appear to be the strategy that was used in the harvest of hard clams at St. Catherines Island. For example, the McQueen hard clams are dominated by individuals that are between two and six years old (figs. 7.7 and 7.8), but their sizes exceed the maximum and minimum of all age classes, up to 30 years old in the modern St. Catherines assemblage (fig. 7.7). Again, there is a great deal of overlap in the physical size of individuals within a population of multiple ages. Protracted and intensive harvest would have eventually removed the older individuals in the population.

CONCLUSION

On St. Catherines Island, the timing of modern hard clam incremental shell growth correlates with the winter/spring (opaque growth) and summer/fall (translucent growth) seasons and may be used to effectively assess the season of hard clam harvest during the Archaic period. Zooarchaeological hard clams from Cannon’s Point, St. Catherines Shell Ring, and McQueen Shell Ring were collected during the winter/spring seasons when opaque growth was at its highest frequency. This is a pervasive pattern that has been documented among many cultural groups living along the southeastern coast of North America. At this level of research, we cannot account for the choice to collect or harvest during the winter/spring seasons.

The life curves and ontogenetic age data provide evidence for intensive exploitation of hard clams from McQueen and Cannon’s Point shell rings. All of the zooarchaeological assemblages represent populations where large, older specimens have been removed from the populations and there is high mortality early in life. This pattern is not characteristic of most southeastern hard clam populations that are in equilibrium. These data are indicative of intensive harvest of the resource.

TABLE 7.1. Modern and Zooarchaeological Survivorship Data of Mercenaria spp. Sampled from St. Catherines Island, St. Simons Island, and Kings Bay, Georgia

Ontogenetic age (years)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Modern St. Catherines Island (N = 221)

Total number of deaths per year

0

2

1

15

19

26

21

27

23

18

13

14

7

6

9

Total number remaining in each age group

221

219

218

203

184

158

137

110

87

69

56

42

35

29

20

Percent of individuals remaining in each age group

100

99.1

98.6

91.9

83.3

71.5

62.0

49.8

39.4

31.2

25.3

19.0

15.8

13.1

9.1

Modern Kings Bay (N = 65)

Total number of deaths per year

1

2

2

7

7

4

4

4

3

5

4

0

1

2

3

Total number remaining in each age group

64

62

60

53

46

42

38

34

31

26

22

22

21

19

16

Percent of individuals remaining in each age group

98.5

95.4

92.3

81.5

70.8

64.6

58.5

52.3

47.7

40.0

33.8

33.8

32.3

29.2

24.6

Archaic Period, St. Simons (N = 35)

Total number of deaths per year

0

2

6

5

8

2

1

4

0

3

0

1

0

1

0

Total number remaining in each age group

35

33

27

22

14

12

11

7

7

4

4

3

3

2

2

Percent of individuals remaining in each age group

100

94.3

77.1

62.9

40.0

34.3

31.4

20.0

20.0

11.4

11.4

8.6

8.6

5.7

5.7

Archaic, St. Catherines Shell Ring (N = 117)

Total number of deaths per year

6

36

36

15

13

5

1

1

1

0

2

0

0

0

0

Total number remaining in each age group

111

75

39

24

11

6

5

4

3

3

1

1

1

1

1

Percent of individuals remaining in each age group

94.9

64.1

33.3

20.5

9.4

5.1

4.3

3.4

2.6

2.6

0.9

0.9

0.9

0.9

0.9

TABLE 7.1. (Continued)

Ontogenetic age (years)

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

Modern St. Catherines Island (N = 221)

Total number of deaths per year

4

5

3

2

5

0

0

0

0

0

0

0

0

0

1

Total number remaining in each age group

16

11

8

6

1

1

1

1

1

1

1

1

1

1

0

Percent of individuals remaining in each age group

7.2

5.0

3.6

2.7

0.5

0.5

0.5

0.5

0.5

0.5

0.5

0.5

0.5

0.5

0.0

Modern Kings Bay (N = 65)

Total number of deaths per year

5

1

1

1

3

1

1

0

1

1

0

1

Total number remaining in each age group

11

10

9

8

5

4

3

3

2

1

1

0

0

0

0

Percent of individuals remaining in each age group

16.9

15.4

13.8

12.3

7.7

6.2

4.6

4.6

3.1

1.5

1.5

Archaic Period, St. Simons (N = 35)

Total number of deaths per year

0

0

0

0

1

0

0

0

0

0

0

0

0

0

1

Total number remaining in each age group

2

2

2

2

1

1

1

1

1

1

1

1

1

1

0

Percent of individuals remaining in each age group

5.7

5.7

5.7

5.7

2.9

2.9

2.9

2.9

2.9

2.9

2.9

2.9

2.9

2.9

Archaic, St. Catherines Shell Ring (N = 117)

Total number of deaths per year

0

0

0

1

0

0

0

0

0

0

0

0

0

0

0

Total number remaining in each age group

1

1

1

0

0

0

0

0

0

0

0

0

0

0

0

Percent of individuals remaining in each age group

0.9

0.9

0.9

TABLE 7.1 — (Continued)

Ontogenetic age (years)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Archaic, McQueen Shell Ring floor deposit (N = 54)

Total number of deaths per year

5

22

9

8

5

1

2

1

1

0

0

0

0

0

0

Total number remaining in each age group

49

27

18

10

5

4

2

1

0

0

0

0

0

0

0

Percent of individuals remaining in each age group

90.7

50.0

33.3

18.5

9.3

7.4

3.7

1.9

Archaic, McQueen Shell Ring general levels (N = 69)

Total number of deaths per year

4

34

18

8

3

0

1

0

1

0

0

0

0

0

0

Total number remaining in each age group

65

31

13

5

2

2

1

1

0

0

0

0

0

0

0

Percent of individuals remaining in each age group

94.2

44.9

18.8

7.2

2.9

2.9

1.4

1.4

0.0

0.0

TABLE 7.1 — (Continued)

Ontogenetic age (years)

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

Archaic, McQueen Shell Ring floor deposit (N = 54)

Total number of deaths per year

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Total number remaining in each age group

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Percent of individuals remaining in each age group

Archaic, McQueen Shell Ring general levels (N = 69)

Total number of deaths per year

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Total number remaining in each age group

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Percent of individuals remaining in each age group

CHAPTER 8: Validation of Annual Shell Increments and Shifting Population Dynamics in Modern and Zooarchaeological Hard Clams (Mercenaria mercenaria) from the Litchfield Beach Region, South Carolina

Douglas S. Jones, Irvy R. Quitmyer, and Chester B. DePratter

Hard clams (Mercenaria spp.) form an alternating pattern of opaque (light) and translucent (dark) growth increments that can be seen in radial cross sections of their shells (fig. 8.1). These increments are thought to represent an annual cycle of growth and reflect changes in shell microstructure and chemistry associated with physiological responses to variations in water temperature or factors related to temperature (Ansell, 1968; Jones and Quitmyer, 1996).

Biologists, paleobiologists, and zooarchaeologists alike have documented the annual periodicity of incremental shell growth in Mercenaria mercenaria populations from the Atlantic coast of North America (Jones, Arthur, and Allard, 1989; Quitmyer, Jones, and Arnold, 1997; Fritz, 2001). These seasonally formed shell increments have been used to estimate the season of hard clam procurement in archaeological sites—zooarchaeological seasonality (Clark, 1979; Quitmyer, Jones, and Arnold, 1997; O’Brien and Thomas, 2008). Less commonly attempted in zooarchaeology are analyses of ancient hard clam population dynamics based on annual shell increments. This approach provides an empirical way to assess potential anthropogenic effects of hard clam harvest on natural populations (Quitmyer, Hale, and Jones, 1985; Quitmyer and Jones, 2000). Such techniques are widely used to monitor the effects of harvesting on modern shellfish beds (Deevey, 1947; Hallam, 1972; Fegley, 2001). In this investigation we explore whether the natural distribution of ontogenetic age classes was disrupted by pre-Hispanic harvesting pressure on hard clam beds in the Litchfield Beach region.

As noted above, shell growth is strongly associated with ambient water temperature. Ansell (1968) demonstrated that optimal shell growth occurs at ~20° C and growth slows as water temperatures approach 9° C or 32° C. The seasonal timing of translucent and opaque incremental shell formation is also known to change across the geographic range of the animal from the Gulf of St. Lawrence to the Bay of Campeche (Fritz, 2001). In the southern part of its range (e.g., South Carolina to Florida) hard clams form the translucent increment during the summer and fall, while opaque shell growth occurs during the late winter and early spring. In the northern latitudes (e.g., mid-Atlantic to New England) this pattern is reversed—translucent increments form in the winter and opaque in the summer. Although the pattern of shell increment differs between northern and southern populations, the preponderance of baseline research demonstrates that a couplet of one opaque plus one translucent increment comprises one year of life.

Within the last decade, some exceptions to these observations have been reported (Fritz, 2001). In a zone between New Jersey and Virginia researchers discovered hard clam populations that deposit four increments during an annual period during certain years—one opaque increment in the spring and another in the fall, plus one translucent increment in the summer and another in the winter (Fritz, 2001). The conventional wisdom of the shell growth literature would seem to indicate that annual increment formation in hard clams could be used to assess the population dynamics and season of harvest of zooarchaeological hard clams throughout their latitudinal range. However, reports of variability in the periodicity of shell formation across space and time indicate a need for caution (Fritz, 2001).

In a more recent study Henry and Cerrato (2007) reported that the timing of formation of shell increments can quickly change within a single locality. Their work reviewed hard clam research published by Jones, Arthur, and Allard. (1989) from Narragansett Bay, Rhode Island, reporting translucent shell increment formation during the winter and opaque increment formation during the summer. These patterns were confirmed by the analysis of oxygen isotope ratios (18O/16O) found in the translucent and opaque increments (Jones, Arthur, and Allard, 1989). In this case, a count of the translucent increments yields the ontogenetic age (in years) of each animal. A size analysis of the age-corrected annual shell increments documented the growth of Narragansett Bay specimens living between 1958 and 1983 (Jones, Arthur, and Allard, 1989).

Henry and Cerrato (2007) found a quite different annual periodic pattern in incremental shell formation in their analysis of shell oxygen isotopes collected from Narragansett Bay in 2005–2006: a translucent increment formed during the winter, an opaque in the spring, a second translucent in the summer, and a second opaque in the fall. They hypothesize that the changes in periodic shell formation resulted from an increase in water temperature in Narraganset Bay (Henry and Cerrato, 2007). If they had relied on the Jones, Arthur, and Allard (1989) baseline interpretation, a count of the translucent increments would have resulted in an overestimate of the mean age of the population. They conclude:

Future studies, even if they are conducted in geographic regions where the annual growth pattern of M. mercenaria has been previously defined, should confirm that the annual pattern has not changed over time due to local environmental fluctuations (Henry and Cerrato, 2007).

Their conclusion is particularly relevant to the study of zooarchaeological assemblages where baseline patterns of periodic shell growth have the potential of changing in response to local and worldwide climatic shifts such as those experienced during the Holocene by Native Americans who populated the coastal environments of the Southeast (Fagan, 2000, 2005). Given the right environmental conditions, the periodicity of incremental shell growth could have changed many times. Recent reports suggest that established baseline patterns of increment formation can even change within a single researcher’s lifetime (Jones, Arthur, and Allard, 1989; Fritz, 2001; Henry and Cerrato, 2007).

In this study we establish a seasonal profile of incremental shell growth using cross sections of Litchfield Beach hard clam shells collected monthly in 2005–2007. These data help to frame the population dynamics of modern hard clams living in the Litchfield Beach estuary (fig. 8.2). We also examine hard clam shell growth in specimens from five zooarchaeological hard clam assemblages sampled from the marshes of the Litchfield Beach, South Carolina (Georgetown County). A sixth sample excavated from nearby Sewee, South Carolina (Charlestown County) is included. These shell middens date between 1690 b.p. and 250 b.p. (table 8.1).

In light of the findings by Henry and Cerrato (2007), we validate the periodicity of the opaque and translucent shell increments in the modern and zooarchaeological specimens by analyzing the ratio of oxygen isotopes (18O/16O) measured in the cross-sectioned shells. We use the annual incremental pattern established from this study to estimate the composition of the ontogenetic age classes of the hard clams contained in the modern and six zooarchaeological assemblages to chart temporal changes in their populations.

Fig. 8.1. Thin, radial cross section of hard clam (M. mercenaria) shell viewed under transmitted and direct light.

TABLE 8.1. Radiocarbon Dates for Hard Clams (M. mercenaria) from Litchfield Beach Shell Middens

Site no.

Beta no.

14C dates 1 σ cal.

14C dates (intercepts)

14C sample depths

38GE570

220164

a.d. 850–1010 (1100–940 b.p.)

a.d. 920 (1030 b.p.)

30–50 cm bs

38GE572

209876

a.d. 180–360 (1170–1590 b.p.)

a.d. 260 (1690 b.p.)

1.4 m bs

38GE579

223880

a.d. 760–910 (1180–1040 b.p.)

a.d. 830 (1120 b.p.)

45–48 cm bs

38GE586

220165 220166

a.d. 1420–1490 (530–460 b.p.) a.d. 1310–1420 (640–530 b.p.)

a.d. 1450 (500 b.p.) a.d. 1390 (560 b.p.)

20–40 cm bs 40–60 cm bs

38GE588

223881

a.d. 1670–1810 (280–140 b.p.)

a.d. 1700 (250 b.p.)

ST, 35 cm bs

38CH44 Sewee clam

229579

a.d. 1420–1480 (530–470 b.p.)

a.d. 1450 (500 b.p.)

45–50 cm bs

METHODS

Archaeological Sites

Chester DePratter and Jim Legg (South Carolina Institute of Archaeology and Anthropology) surveyed 18 shell middens located in the tidal marshes of the Litchfield Beach estuary (fig. 8.2) in 2005. With the exception of one eastern oyster shell (Crassostrea virginica) midden (8GE572), all of the sites were composed of hard clam shells with the isolated remains of Atlantic ribbed mussel (Geukensia demissa) and stout tagelus clam (Tagelus plebeius). Pottery sherds were rarely encountered, while carbon lenses were observed during the excavations. The middens are located in the salt marsh and some extend below the present high tide line, indicating that sea level was at a lower stand than it is today.

We report on only those sites where hard clam sample size is greater than 30 interpretable specimens and where the deposits were radiocarbon dated (tables 8.1 and 8.2). This represents a total of six archaeological sites in the Litchfield Beach locality (fig. 8.2; table 8.2). Twelve sites remain to be dated and analyzed (fig. 8.2).

Fig. 8.2. Location of the Litchfield Beach archaeological shell middens.

TABLE 8.2. Descriptive Statistics of Ontogenetic Age (years) of Modern and Zooarchaeological Hard Clams from the Litchfield Beach Region

Litchfield

38GE588

38CH44

38GE586

38GE570

38GE579

38GE 572

Modern

250 b.p.

500 b.p.

560 b.p.

1030 b.p.

1120 b.p.

1690 b.p.

Mean

7.88

7.48

6.83

3.17

4.95

5.00

7.75

Standard error

0.15

0.39

0.44

0.20

0.25

0.32

0.50

Median

8

7

6

3

5

5

8

Mode

7

7

5

2

5

4

8

Standard deviation

2.63

2.63

3.05

1.18

1.68

1.97

3.00

Sample variance

6.90

6.93

9.29

1.40

2.84

3.89

8.99

Range

13

11

14

4

6

9

12

Minimum

3

3

2

2

2

3

4

Maximum

16

14

16

6

8

12

16

Count

305

46

48

36

44

38

36

Confidence interval (95.0%)

0.30

0.78

0.89

0.40

0.51

0.65

1.01

Litchfield—Modern Proxy

A two-year reference collection of modern hard clams (N = 1055) was assembled by Chester and Kalla DePratter who collected approximately 45 live specimens each month over the two-year interval, March 2005–March 2007. The purpose of the study was to associate the timing and periodicity of incremental shell growth with the seasons of the year and to document the population dynamics (ontogenetic age distribution) of the hard clams living in the Litchfield Beach estuary. The annual patterns observed in these data are then used to provide a temporal assessment series of zooarchaeological hard clams from the five Litchfield Beach sites.

Modern hard clams were hand collected live in the shallows of Clubhouse Creek. Scientific Permit #0984 was issued by South Carolina Department of Natural Resources because over the past 20 years the water quality of the estuary has not allowed for healthy commercial or recreational harvest of hard clams. We suggest that the modern Litchfield Beach assemblage may closely resemble a natural population because there had been no harvesting pressure over an extended period.

The specimens were frozen, allowed to thaw, cleaned of their soft tissue, and the shells were numbered and stored. Eventually the shells were transported to the Florida Museum of Natural History, Gainesville, for measurement and analysis. The anterior-to-posterior length of the right valve of each specimen was measured using digital calipers attached to a personal computer. This allowed for the direct input of shell measurement data into Microsoft Excel spreadsheets where all descriptive statistics were calculated.

We followed the methods of Quitmyer, Jones, and Arnold (1997) to expose and characterize the incremental shell growth patterns. The right valve of each specimen was radially cross-sectioned along the greatest growth axis, from the umbo to the ventral margin, using a water-cooled lapidary saw fitted with a Mark V alumina oxide blade (Quitmyer, Jones, and Arnold, 1997). The alumina oxide blade produced a polished cross-sectional surface that was examined with the unaided eye and/or microscopically (10×, 20×) with transmitted light.

For the purposes of our study, the frequency of individuals in either the translucent or opaque phase of shell growth was calculated for each month to document a pattern, or annual profile that is presented as a histogram for the modern hard clam assemblage. All of the zooarchaeological samples were prepared and analyzed in accordance with the methods outlined for the modern comparative collection of hard clams (Quitmyer, Jones, and Arnold, 1997; Quitmyer and Jones, 2000).

Isotopic Validation of Incremental

Shell Growth Patterns

The seasonal variability in the oxygen isotope record contained in modern and zooarchaeological hard clams provides an independent method of validating the annual periodicity of incremental shell growth. Bivalves generally produce shell (CaCO3) at or very near oxygen isotopic (18O/16O) equilibrium with the ambient seawater (Wefer and Berger, 1991). The exchange reaction is temperature dependent; thus, where the isotopic composition of ambient seawater remains relatively uniform, warm seawater temperatures are indicated where the oxygen isotopic composition (δ18O) is depleted, while cooler temperatures are indicated as the oxygen isotopic composition becomes enriched (Epstein and Lowenstam, 1953; Grossman and Ku, 1986). It is for this reason that we plot the isotopic values in an inverted fashion with negative (warm, up) to positive (cool, down) (Epstein et al., 1953).

Six zooarchaeological and two modern shells were randomly selected for isotopic analysis. The shells were radially cross-sectioned from the umbo to the ventral margin and glued to a glass petrographic microscope slide using two-part epoxy. Each specimen was then mounted on a Buehler Isomet saw equipped with a low concentration diamond wafering blade. A second radial cross section was made which produced a thick section for sampling. Between one and three samples of shell carbonate were milled from the opaque and translucent increments using a Merchantek Micromill equipped with a tungsten carbide bit. The samples were taken in ontogenetic sequence from the youngest to oldest part of the shell (i.e., umbo to ventral margin).

The isotopic analyses were conducted at the light stable isotope mass spectrometry laboratory, Department of Geological Sciences, University of Florida. The powdered shell samples were analyzed according to standard techniques, which involved an initial reaction in vacuo with 100% orthophosphoric acid at 70° C for 10 minutes. An online, automated, carbonate-preparation system (Kiel III) facilitated the production and purification of the evolved CO2 gas. The isotopic differences between the derived CO2 gas and the VPDB standard were determined with a Finnigan-MAT 252 isotope ratio mass spectrometer equipped with a Kiel III carbonate preparation system. All values are reported in standard δ notation where:

δ18O = [(18O/16O)[sample]/(18O/16O)[standard]-1] × 103 per mil

The weight of the individual microsamples was so small that replicates of unknowns could not be run. However, variation among standards run before and after sample strings was less than ± 0.03 per mil (‰).

Ontogenetic Age

Based on the annual cycle of incremental shell growth observed in the shell cross section and validated from the isotopic study, the ontogenetic age (in years) of each modern and zooarchaeological hard clam was determined by counting the number of translucent shell increments seen in the radial cross section of the shells. The mean age and 95% confidence interval around the mean was calculated for each archaeological site. It was then possible to ascertain which of the sample sites were statistically different (p < 0.05) by noting whether or not their confidence intervals overlapped. This technique is straightforward, easily interpretable, and conservative.

Once the ontogenetic age was determined for every specimen, the rate of survivorship was calculated as the percentage of the population surviving during each year of life. These dynamic data were plotted as survivorship curves that facilitate the comparison of the modern and zooarchaeological samples (Deevey, 1947; Hallam, 1972; Cerrato, 1980).

RESULTS

Observed Incremental Shell Growth

Modern Hard Clams: Figure 8.3 presents the monthly frequency of individual clams (N = 507) forming the translucent and opaque increments in relation to annual monthly sea surface temperature (SST) and precipitation. The data show that during each month some proportion of the hard clam population is forming the translucent increment in their shells. Opaque shell growth is most prevalent between February and June. Thereafter, there is a distinct decline in opaque shell growth as SST increases toward summer maximum values. We note that precipitation in the region tracks SST and also reaches its maximum during the warm season. No opaque shell growth was observed in August and September when SST reached the annual maximum (August SST = 28° C). When all of the monthly data are pooled (fig. 8.3), annual translucent shell growth, relative to opaque, dominates the modern Litchfield Beach hard clam population.

Zooarchaeological Hard Clams: In contrast to the modern hard clams, the opaque shell increment is most frequently identified in all of the zooarchaeological assemblages (fig. 8.4). Because the δ18O composition of the modern and zooarchaeological shells (figs. 8.5–8.7) indicate comparable temperature regimes (isotopic values ranging between –2.00 and +1.00 ‰), such a pattern most likely resulted from the preferential, seasonal harvest of hard clams during the winter and spring when opaque shell growth is most prevalent.

Isotopic Validation

The translucent and opaque shell growth increments were microsampled from two modern hard clams collected live in March 2005 and January 2007 (fig. 8.5). δ18O values ranged between –1.75 and 1.48 in the 2005 specimen and between –2.40 and 1.63 in the 2007 shell. Figure 8.5 shows a pattern of growth where each translucent increment is characterized by depleted or light δ18O values (warm SST) while the opaque increments are relatively enriched (cooler SST). These data confirm the monthly observations of marginal shell growth, which indicate that translucent increments are seasonally formed during the summer and autumn (figs. 8.1 and 8.3). Because only one translucent increment forms per year, the total number of translucent increments counted in a shell cross section yields the ontogenetic age (in years) of each specimen.

Carbon isotope (δ13C) profiles from the two modern shells range between –4.06 and –0.36. The δ13C profiles weakly track the δ18O values (fig. 8.5).

The results of the isotopic analyses from four zooarchaeological hard clams, excavated from three sites dating between 250 and 560 b.p., are presented in figure 8.6. The δ18O values range between –2.20 and 1.51. In all cases, the translucent increment represents warmer SST (depleted δ18O), while the opaque increments formed in cooler conditions (enriched δ18O). δ13C variation shows a positive correlation with the seasonal changes in the δ18O composition (fig. 8.6). The correlation is much stronger than observed in the data from the modern specimens.

The three zooarchaeological hard clams from the sites that date between 1040 b.p. and 1690 b.p. share a similar oxygen isotopic pattern (fig. 8.7) with the modern shells and the other zooarchaeological shells. Among the three hard clams (fig. 8.7) the δ18O values range between –2.04 and 1.70. The oxygen isotope data indicate that all translucent increments formed during the warm season and the opaque increments during cooler SST conditions. The δ13C profiles also show a positive correlation with δ18O as seen in the previous zooarchaeological specimens.

The isotopic data suggest there is a difference in the relationship between δ13C and δ18O in the modern versus the zooarchaeological shells. In all but one of the zooarchaeological shells (figs. 8.6 and 8.7), the correlation between δ13C and δ18O is stronger than in the modern specimens (fig. 8.5). This reflects the natural seasonal input of freshwater into the estuary, primarily during the wet season. In contrast, the modern estuary receives abundant freshwater year-round from septic tanks, irrigation, and storm water runoff.

Size vs. Age

Hard clam populations living in the Southeast display a great deal of variation in age among similar-sized individuals (Walker and Tenore, 1984; Quitmyer and Jones, 2000; Fegley, 2001). This pattern also exists in the modern Litchfield Beach hard clam population that was collected in 2005–2007. For example, the anterior to posterior range in size of the three-year-old clams encompasses a sizable proportion of all other age classes in the sample (see box in fig. 8.8). The shells range in age between three and 16 years (N = 305, mean = 7.9, S.D. ± 0.15), while the anterior-to-posterior length ranges between 64.3 and 84.5 mm (mean = 64.3 mm, S.D. ± 0.41).

Mean Ontogenetic Age and Survivorship

As noted above there is considerable overlap in the size range of consecutive age classes in each hard clam population. It is for this reason that we rely on ontogenetic age as a measure of the population dynamics of the modern and zooarchaeological assemblages. A plot of the mean age and 95% C.I. of the seven samples, in temporal order, shows a significant decline in the mean age between 1690 b.p. and 560 b.p. and a subsequent rebound to the present (table 8.2; fig. 8.9). The 95% C.I. of the three youngest samples and 38GE52 (1690 b.p.) overlap and are statistically indistinguishable; however, the samples from 1120 b.p. to 560 b.p. are statistically different.

A plot of the survivorship curves also shows temporal changes in the survivorship of the seven hard clam assemblages (fig. 8.10). The survivorship curves for the three samples dating between 1120 b.p. and 560 b.p. (solid symbols in fig. 8.10) show a substantial reduction in the mean survivorship and the right tail of the curve is truncated relative to the younger samples (500 b.p. to the present) or the earliest sample (1690 b.p.).

Fig. 8.3. Monthly frequency of specimens forming translucent or opaque shell growth increments from March 2005 to March 2007 in hard clams collected from the estuary at Litchfield Beach, SC. Sea surface temperature (°C) and precipitation (cm) from nearby North Myrtle Beach, SC.

Fig. 8.4. Percentage of translucent and opaque incremental shell growth identified in modern and zooarchaeological hard clams from the Litchfield Beach region. Abbreviations: T = translucent shell growth; O = opaque shell growth.

Fig. 8.5. Variation in oxygen (18O/16O) and carbon (13C/12C) isotopic composition in the translucent and opaque growth increments of modern hard clams from the Litchfield Beach region.

Fig. 8.6. Oxygen (18O/16O) and carbon (13C/12C) isotopic composition of the translucent and opaque growth increments from zooarchaeological hard clams (M. mercenaria) from the Litchfield Beach region.

Fig. 8.7. Oxygen (18O/16O) and carbon (13C/12C) isotopic composition of the translucent and opaque growth increments from zooarchaeological hard clams (M. mercenaria) from the Litchfield Beach region.

Fig. 8.8. A comparison of age (years) versus anterior-to-posterior (A/P) shell length in modern hard clams (M. mercenaria) from the Litchfield Beach estuary.

Fig. 8.9. The mean ontogenetic age and 95% confidence interval around the mean of modern and zooarchaeological hard clams (M. mercenaria) from the Litchfield Beach region.

DISCUSSION

Documentation of the yearly pattern of growth increment formation in the shells of modern hard clams establishes a baseline proxy of annual incremental shell growth that can be used to evaluate the population dynamics of zooarchaeological hard clams excavated from the Litchfield Beach region. The shell microstructural data indicate that in the modern population the opaque increments form during a short seasonal interval between late winter and spring. These alternate with translucent shell growth increments that are most pervasive during the summer and autumn as seawater temperature warms.

Analyses of oxygen isotopes (δ18O) in the modern and zooarchaeological shells independently verify the seasonal periodicity of the two alternating shell increments. In all cases, enriched values of δ18O indicative of cool water conditions characterize the opaque increment and depleted δ18O values (warm conditions) characterize the translucent increment. This periodic pattern (chemical and microstructural) is consistent with other modern seasonal and zooarchaeological studies of hard clams reported from the Southeast (Clark, 1979; Quitmyer, Jones, and Arnold, 1997; Fritz, 2001; Andrus and Crowe, 2008; O’Brien and Thomas, 2008). These findings verify that a couplet of one opaque and one translucent shell growth increment marks one year of life and justifies its use in characterizing the population dynamics of modern and zooarchaeological hard clam assemblages. Further, the data indicate that this pattern has remained constant in the Litchfield Beach region for at least the last 1700 years.

The population dynamics of an organism like the hard clam are influenced by its ontogenetic age composition, growth rate, mortality (survivorship), and recruitment. Human harvesting pressure has been shown to alter the population dynamics of hard clam beds, in particular the mean ontogenetic age and survivorship (Walker, 1989). For example, Walker (1989) has shown that small, densely populated hard clam beds are easily overfished. In 1981 a small bed (90 m2) containing 49 clams per square meter was illegally harvested (hand collecting) in the Wassaw Island National Wildlife Refuge of coastal Georgia. In a one-week period, the population declined to 22 individuals per square meter. In fact, hard clam populations of the southeastern United States are vulnerable to harvesting pressure because of their habitat preferences, recruitment, and distribution within those habitats.

Hard clams are one of the most abundant, large-bodied, infaunal suspension feeders living in soft substrates (Fegley, 2001). In the Southeast they generally occupy the intertidal zone of estuarine creeks where they tend to be restricted to heterogeneous substrates (Walker, 1989). They are typically found in densely packed, circumscribed beds among oysters, shell deposits, and to a lesser extent sand, mud, and sandy mud (Walker and Tenore, 1984; Fegley, 2001). Such a configuration facilitates rapid, intensive harvesting.

Recruitment is a gradual process that is inconsistent from year to year where very few individuals enter the adult stage (Malinowski, 1985). Because of sparse, sporadic settling of spat, major sets are rare and hard clam populations are dominated by larger individuals (Walker, 1989). Commercial harvesting along the Georgia and South Carolina coasts represents a minimal activity. Because of light harvesting pressure, it has been suggested that many of the beds resemble populations that are in equilibrium (Fegley, 2001). This may extend to other areas of the Southeast where harvesting is limited. The Litchfield Beach hard clam population is one such example where harvesting has been limited or nonexistent for decades due to poor water quality.

Where hard clam beds are fished, larger individuals are at greater risk than small to medium-sized individuals (Fegley, 2001). It has been suggested that the larger hard clam shells shelter the smaller individuals from predators (Walker, 1989). As larger individuals are removed from their beds there may be an increase in predation on smaller specimens (Walker, 1989), which further reduces the number of individuals that might reach maximum age.

Although hard clam beds tend to be dominated by larger individuals, size classes may vary with habitat type, predator diversity, and density (Walker and Tenore, 1984). As we have shown above, there is considerable scatter in the size-versus-age relationship (Fegley, 2001). Because of this, variations in mean shell size are not a reliable indicator of hard clam population dynamics and their relationship to harvesting pressure.

In light of our understanding of hard clam biology and ecology, we can consider the ontogenetic age composition and survivorship of the hard clam assemblages that span nearly 1700 years at Litchfield Beach. The mean ontogenetic age of the earliest zooarchaeological assemblage (1690 b.p.) resembles that of the modern, unharvested beds. Between 1120 b.p. and 560 b.p. the data suggest the zooarchaeological hard clams were intensively harvested and the mean age of the population declined significantly. The survivorship curves also show a loss of younger individuals ranging between one and four years of life and fewer individuals reaching maximum age. After 560 b.p. there is a rebound in the ontogenetic age composition and survivorship that resembles the assemblages dating between 500 b.p. and the present. These are also similar to the earliest zooarchaeological sample (1690 b.p.).

The question might naturally be posed as to whether the diminished mean age composition of the ancient hard clam populations observed in this study could be the result of natural causes as opposed to human harvesting pressure (i.e., anthropogenic impact on the beds). Like many infaunal bivalve molluscs, hard clams refuge themselves in size from nonhuman predation pressures (e.g., fish, crabs, sea stars, boring gastropods, whelks), which are typically concentrated upon the smaller, juvenile components of the population (Walker, 1989). Intensification of natural predation pressure would therefore have the net opposite effect of what is observed in the zooarchaeological assemblages by increasing the mean ontogenetic age (size) of the population. In contrast, human exploitation that blindly extracts clams from the substrate puts the largest (generally oldest) individuals at greater risk of being collected. In the zooarchaeological assemblages that appear to have been impacted by intensive harvesting, the older members of the population are missing from the zooarchaeological assemblages (fig. 8.10).

We cannot fully reject unseen environmental conditions that could have affected the dynamics of the various Litchfield Beach hard clam populations. However, previous research has shown that the pattern of intensive hard clam exploitation is nonuniform over space and time in southeastern North America (Quitmyer and Jones, 2000). At some localities, the age class composition is diminished, while at other sites dating to the same time period, there are samples that seem to have been collected from unharvested beds. Quitmyer and Jones (2000) have also documented the reduction in the zooarchaeological age classes of hard clams in some locations in archaeological sites, while in other areas of the same sites there is no evidence for concentrated harvesting. Exposure time to humans and intensive harvesting are the two common variables that exist when heavy exploitation of hard clams is identified. Similar observations are well documented in the zooarchaeological record (Quitmyer, Hale, and Jones, 1985; Szabó and Quitmyer, 2008; Quitmyer and Jones 2000; Marcello and Thomas, 2002; Quitmyer, 2003; Peacock, Haag, and Warren, 2004; Erlandson et al., 2008; Rick and Erlandson, 2008).

This is the same pattern observed in the Litchfield Beach region. With exposure time to humans and evidence for intensive collecting, there is a clear and precipitous decline in the mean ontogenetic age (in years) between 1690 b.p. and 560 b.p. We cannot account for the subsequent increase in the mean age of the populations after 560 b.p., but it is clear that harvesting pressure was removed and the age class composition returned to what may be considered indicative of naturally occurring populations. This pattern may have been the result of intensive harvest in the region and a subsequent abandonment of the beds, thus allowing their age class compositions to equilibrate. Alternatively, could harvesting pressure have been abated by Hispanic incursion into the region? Shortly after 560 b.p., Hispanic explorers entered the Southeast, resulting in a profound disruption of the Native American population.

Fig. 8.10. Survivorship curves of modern and zooarchaeological hard clams (M. mercenaria) from the Litchfield Beach region.

CONCLUSIONS

In this research we combine microstructural and oxygen isotopic approaches to document and validate the fundamental pattern of periodic, incremental shell growth for hard clams living in the Litchfield Beach region. The two-year longitudinal study of incremental shell growth (observational data) demonstrates that the opaque (light) growth increment forms in the late winter and spring when sea surface temperatures approach the optimum for hard clam growth (~20° C) and the translucent (dark) increment forms as the sea surface temperature increases toward the summer maximum (~32° C). The oxygen isotopic composition of the opaque and translucent shell increments validate the observational data. A couplet of one opaque and one translucent shell growth increment represents one year of life. These data also confirm a similar pattern in the zooarchaeological hard clam assemblages for the past 1700 years in the region. This periodic pattern of incremental shell growth is consistent with previous research from the southeastern Atlantic coast of the United States.

With these data in hand we can evaluate the season of hard clam harvest in the middens, ontogenetic age, and survivorship of the modern and zooarchaeological populations in the Litchfield Beach region. The data show that all of the zooarchaeological harvesting occurred during the winter and spring seasons. There was intensive harvesting pressure between 1690 b.p. and 560 b.p. where hard clams were consumed at an intensive rate. The mean ontogenetic age class composition declined from 7.8 years to 3.2 years. After 560 b.p., harvesting pressure was removed and the survivorship of the hard clam assemblages rebounded with the mean ontogenetic age rising to 7.9 years.

This pattern of intense exploitation appears to have occurred more than one time and in other geographic locations in the Southeast. Like many molluscan taxa, hard clams are sensitive indicators of harvesting pressure. Where there is evidence for dense human populations, evidence for sedentism, or in places where hard clams are a major focus of subsistence behavior, changes in the ontogenetic age classes and survivorship can be identified.

Pre-Hispanic harvest of hard clams extended across a wide temporal and geographic range. The decisions that resulted in the changes to the zooarchaeological hard clam population dynamics appear to be more intrinsic to the human species rather than associated with the level of cultural complexity.

CHAPTER 9: Reevaluating the Use of Impressed Odostome (Boonea impressa) as a Season-of-Capture Indicator for Oysters

Deborah Ann Keene

Boonea impressa are small (less than 1 cm) parasitic gastropods that feed on oysters and are found along the Atlantic and Gulf coasts of North America (fig. 9.1). Although B. impressa were probably not deliberately gathered by humans as a food source, the oysters to which they were attached were gathered in large amounts. B. impressa are frequently found in archaeological middens, although a small screen size (0.7 mm) must be used to recover them all.

The use of Boonea impressa as a season-of-capture indicator for archaeological oysters was first devised by Russo (1991) and his ideas have laid the groundwork for others using this species (see Cannarozzi, chap. 10, this volume). Russo (1991) hypothesized that determining the season of death for B. impressa would reveal the season of death for the oysters to which they were attached. His hypothesis rests on the assumptions that the majority of B. impressa are born at the same time of year, live only for about one year, and increase in size throughout the year. Therefore, one could determine the season in which they died by their size. To test his hypothesis, he collected and measured modern samples of B. impressa from the northeastern coast of Florida for 14 months. He used these data to develop a model of yearly growth based on shell length. The growth curve is divided into shell length size classes representing spring, summer, autumn, late autumn, winter, and late winter (table 9.1). The shell length size classes were determined from the modal range, or the most common lengths collected during a particular season, rather than the average length of all the shells collected. Russo did this because, although most B. impressa are born at one time of the year, a smaller percentage is born throughout the year. Using a modal range theoretically isolates the larger birth cohort and negates any effects of the other birth cohorts in determining the season of death. He did not test his model on known samples, but did apply them to archaeological assemblages. Russo (1991) has carefully considered many of the drawbacks of assessing seasonality (i.e., mean length vs. mode size categories); however, there are several additional problems that must be addressed. These include variation between species in different environments, constant reproduction throughout the year, inconsistent growth patterns, feeding habits of juveniles, and lack of specific knowledge of many aspects of growth, reproduction, and behavior. Russo’s application and these issues are the focus of this chapter.

Fig. 9.1. Drawing of Boonea impressa.

TABLE 9.1. Size Classes Formulated by Russo (1991)

Season designation

Calendar months included

Shell length (mm)

Spring

May, June

1.1–2.5

Summer

July, August

2.6–3.5

Autumn

September, October

3.6–4.0

Late autumn

October, November

4.1–4.5

Winter

November, December, January

4.6–5.0

Late winter

February, March, April

5.1–5.5

Location and Environment

Morphological characteristics of Boonea differ among geographic locations and environments. White, Kitting, and Powell (1985) collected samples of Boonea impressa in October, December, March, May, and July (1981–1982) on Mud Island, Texas. These samples were compared to shells collected at Virginia Creek and Williston Creek, North Carolina. Multiple measurements of these collections indicated that the North Carolina specimens were larger overall (White, Kitting, and Powell, 1985: 42). However, no cause is suggested for this size difference. It may be due to temperature difference between North Carolina and Texas, or it may be that one collection was made in 1981–1982 while the other collections were made in the 1970s.

White, Kitting, and Powell (1985) counted sperm and oocytes in a laboratory sample of Boonea impressa collected from Big Slough, Texas, and found that sperm was present in all months but December. The authors suggest that the lack of sperm in December may be due to cold temperatures. If the cold temperatures in Texas can affect sperm production, it is likely that B. impressa in more northerly climates would not have the same birth seasons as populations in Texas and Florida. This means that B. impressa size classes would not be universal in determining season of capture. This is illustrated by Cannarozzi’s (chap. 10) work from St. Catherines Island. Her size classes are markedly different from Russo’s (1991) Florida size classes.

Morphological differences have also been observed in Boonea impressa populations that live in the same geographic location but in different environments within that location. Porter, Howie, and Deriso (1979) compared B. impressa and Boonea seminuda specimens from North Carolina estuaries with B. seminuda specimens from offshore environments. The estuarine samples of B. impressa and B. seminuda shared more selected characteristics than the B. seminuda from different environments did with each other (Porter, Howie, and Deriso, 1979: 44).

Both the White, Kitting, and Powell (1985) and Porter, Howie, and Deriso (1979) studies indicate that morphological differences in Boonea can be caused by environment and geography. However, the extent of these differences is not yet known, and more work needs to be done, especially with the effects of temperature on reproduction and growth. The available data indicate that size ranges to determine season of capture may only be useful in a small geographical area, highlighting the importance of developing ecological analogies using data collected as near as possible to the sites being studied (see Cannarozzi, chap. 10).

Reproduction

The Boonea impressa method relies on the assumption that the majority of individuals are born in late spring/early summer and live for approximately one year (Russo, 1991: 209). However, this assumption may not be supported by available data. Russo (1991: 208) cites two studies of B. impressa in addition to his own. The first is Wells (1959), and the second is White, Kitting, and Powell (1985).

The Wells (1959: 142) article states that “the largest collection of young were made in June and July, when they formed by far the most numerous class in the population.” However, Wells (1959) does not report specific percentages. White, Kitting, and Powell (1985: 39) report percentages of young (0.5–1.0 mm wide) collected each month. July contained the largest number of young at 55%, however, December contained 22%, October contained 10%, and March 5%. The July sample may have been affected by climatic conditions and may be lower than normal, but this simply illustrates the point that the Boonea impressa demography is dynamic from one year to the next. Regardless, White, Kitting, and Powell (1985) show that a third of the population is born in seasons other than summer, and there is a fairly large birth rate increase in December, albeit smaller than the June/July increase.

This second reproductive peak in the annual growth curve (December) would cause many problems in interpreting archaeological assemblages by using Boonea impressa to determine season of capture. An archaeological assemblage consisting of a December population would consist of about 25% young B. impressa, about 55% middle-aged individuals, and about 20% of the individuals would reflect a variety of other age groups. This distribution would result in a bimodal growth curve suggesting spring and winter collection rather than just December. As these populations grow, the bimodal curve will continue to shift, producing a bimodal distribution that does not reflect the actual collection times of the B. impressa.

Inconsistent Growth Patterns Within Populations

Two of the key assumptions needed when using Boonea impressa as a season-of-capture indicator is that “the average size … increases throughout the year” and that the lengths are comparable across time (Russo, 1991: 209). In Wells (1959), the collection of B. impressa takes place over a period of 18 months and 16 collections are made (fig. 9.2). Collections were taken during two successive years for the months of May, June, July, August, September, and October. One collection was taken for July/August in 1956; separate July and August collections were taken in 1955. As the length means from these collections would certainly differ from one another, they will not be included in this chapter. The mean length in May 1955 is approximately 2.5 mm, and the mean in May 1956 is approximately 4.25 mm. The mean length in June 1955 is approximately 1.5 mm and the mean in June 1956 is approximately 2.5 mm. The mean for September is about the same for both years. In October 1955, however, the mean is slightly over 3.0 mm, while in October 1956, the mean is nearly 4.0 mm. Clearly, the size means vary between years, in this case up to 1.75 mm, and this is precisely why Russo (1991) uses modal size ranges rather than mean. Modal sizes would do a good job of isolating a specific cohort, but if that cohort measured as little as 0.2–0.4 mm larger than it did in the previous year, Russo’s (1991) particular modal size ranges would not accurately predict the season of capture.

The White, Kitting, and Powell (1985: 38) studies of Boonea impressa from Mud Island, Texas, contain data indicating that the growth patterns of their population of B. impressa do not match with the growth patterns seen in Russo’s (1991) population. Although the width of the sample populations collected in October, December, March, May, and July increase throughout the year, a chi-square test indicated that there was not a significant difference in size between the March and May populations (p < 0.05). So although Russo’s (1991) assumption that B. impressa generally grow larger throughout the year is supported, the month in which the older population dies and the new one takes over is variable. This conclusion is supported by the differences between Russo’s (1991) and Cannarozzi’s (chap. 10) size classes.

It is clear from these data that a population of Boonea impressa from the same area will have variable growth characteristics from year to year. If the growth of B. impressa is related to temperature, as suggested earlier, this would explain the changes in size from year to year and would seriously impact the use of B. impressa size to determine season of capture.

Fig. 9.2. Length distribution data from Wells (1959). Reprinted with permission. Colored highlights added by the author.

Feeding Habits

Another variable is the feeding habits of juvenile Boonea impressa. Powell et al. (1987) observed juvenile B. impressa frequently feeding on Crepidula plana and other Crepidula species in Texas. During a controlled experiment in which juvenile B. impressa were placed in a tank with oyster spat and C. plana for five days, all juveniles attached to the C. plana by the fifth day and none were found on the oyster spat. Adults always preferred the oyster. Although this is a particular instance indicating that juveniles and adults have different feeding habits, it demonstrates a general behavior that could affect distribution of B. impressa in archaeological assemblages. Feeding on any species other than oyster could skew the number of juveniles in a random sample, because the smallest B. impressa might not be brought to the archaeological site unless that species was present. Thus, the smallest size class would be underrepresented and larger individuals, those preferring oysters, would be numerically more common. This would result in consistently finding a larger number of mature individuals.

In fact, most applications that use Boonea impressa do find a larger number of mature individuals. When Russo (1991) applied the method to archaeological samples, all 13 of the features and middens contained B. impressa size classes representing late autumn or winter components (his larger size classes). Two features had smaller spring components, one had a smaller summer component, and one had a larger summer component. Fradkin (2008) measured over 6000 B. impressa from the Greenfield site, Florida, to determine season of capture. Again, all the components included autumn and late autumn captures (using Russo’s [1991] size classes) with one having an additional summer capture. Cannarozzi (chap. 10) created her own size classes using local B. impressa near St. Catherines Island. The most numerous size class for both her archaeological samples was spring, which corresponds roughly in size to Russo’s (1991) autumn, late autumn, and winter size classes (approximately 4–6 mm in length).

Russo’s (1991) size classes were used by the author on samples of Boonea impressa taken from Grove’s Creek Site, Skidaway Island, Georgia. The B. impressa shells were sorted from flotation samples taken from a 1 × 1 m midden unit and passed through 0.50 mm mesh. All shells were examined under a low-power microscope to confirm that they were unbroken. The length of each shell was measured with a pair of digital calipers. The measurements were taken from the apex to the abapical end and were divided into the modal length size classes outlined in Russo (1991). The data (N = 79) indicated primarily autumn season of capture (fig. 9.3). It should be noted that stable isotope analysis was performed on oysters recovered from the same excavation unit and none indicated an autumn season of capture (Keene, 2004). However, this discrepancy may be the result of small sample size (N = 8 oyster shells).

All four applications of the method described above find larger percentages of Boonea impressa in the 4–6 mm size class. This supports the hypothesis that primarily larger B. impressa are being recovered at greater rate than smaller B. impressa. Recovery bias may be due to feeding habits, but it may also be due to increased breakage of younger B. impressa, or recovery methods. With only four studies, these conclusions are preliminary. The Russo (1991) and Fradkin (2008) assemblages do contain significant numbers of spring and summer size classes. However, this could be due to reasons other than a spring or summer collection of oysters. First, multiple years might be represented in the archaeological sample, with one year producing smaller or larger adult B. impressa than another year. Second, a bimodal distribution of larger and smaller individuals might be caused by a population collected during the season when there is an influx of young B. impressa into an existing population of mature B. impressa.

Fig. 9.3. Season of capture for Grove’s Creek site Boonea impressa shells using Russo method with a 0.50 mm screen.

Current State of Knowledge Concerning Boonea impressa

The last issue has been mentioned throughout, and that is general lack of information about Boonea impressa growth, reproduction, and behavior. The major studies were conducted in North Carolina (Wells, 1959; Porter, Howie, and Deriso, 1979) and Texas (White, Kitting, and Powell, 1985; Powell et al., 1987). Some data indicate that these populations are morphologically distinct, but are insufficient to explain the degree of difference or why there are differences. Reproductive behavior may be affected by temperature (White, Kitting, and Powell, 1985), but this is inconclusive. Until we know how reproduction and growth are affected by environmental factors, using B. impressa as a method to determine season of capture for oysters may not be reliable, and it is clear that size classes are not universal.

There are several avenues that can be taken to evaluate the merits of this method for indirectly assessing season of capture for oysters. The first would be to recreate an archaeological midden sample with Boonea impressa from known collection dates. Shells from different years and months could be mixed and then measured by a person who does not know which seasons are included. Shells from the same month and different years should be tested similarly. Increased overall sample size as compared to previous studies is key. Modern collections need to be taken in several environmental zones over several years to record clinal variations in growth. Cannarozzi (chap. 10) has already done a multiyear collection at St. Catherines Island. If molluscan researchers and archaeologists from coastal universities collaborate, this project would not be as daunting as it may seem. Although there are certainly issues that need to be addressed, the cost effectiveness and ease of this method for determining season of capture indicate that it should not be abandoned.

CHAPTER 10: Estimating the Season of Harvest of the Eastern Oyster (Crassostrea virginica) from St. Catherines Shell Ring

Nicole R. Cannarozzi

Determining seasonal of use of the animals on St. Catherines Island is an important step toward understanding settlement and subsistence strategies through time. White-tailed deer, sharks, catfishes, hard clams (Mercenaria spp.), and impressed odostomes (Boonea impressa) have been used as proxies for seasonal procurement of resources on St. Catherines Island (Thomas, 2008: 877). Evidence from one or more of these animals for year-round use of resources, if not residence, is present for all cultural periods on St. Catherines Island. However, evidence for seasonal resource procurement when the St. Catherines Shell Ring was occupied is very rare for the St. Simons cultural period (3000 b.c.–1000 b.c.) (Thomas, 2008: 1001).

One of the primary ways in which the question of seasonal settlement of coastal sites has been addressed is through the measurement of annual growth increments of bivalve species such as the hard clam and, less frequently, the eastern oyster (Crassostrea virginica) (Claassen, 1986; Quitmyer, Hale, and Jones, 1985; Quitmyer, Jones, and Arnold, 1997; Quitmyer, Jones, and Andrus, 2005). Oysters are often the most numerous component in southeastern coastal shell middens, but have not been considered reliable proxies for seasonality because morphological features have not been found to correlate with seasons. Additionally, difficulties are encountered in interpreting the isotopic record of estuarine organisms due to mixing of freshwater and ocean water with varying salinities and oxygen isotopic signatures. Season of death studies using visual analysis of shell growth structures have been successful on subtidal and archaeological oysters in the Chesapeake Bay region where studies have shown that these oysters deposit identifiable winter growth breaks (Custer and Doms, 1990; Kent, 1992; Herbert and Steponaitis, 1998; Kirby, Soniat, and Spero, 1998). Techniques that measure growth structures are unsuitable for use on intertidal oyster populations in the Southeast because of the sensitivity of this species to extreme changes in the environment (Russo, 1991). Changes in water temperature and salinity, storm events, and even spawning may cause deposition of multiple growth breaks throughout the year (Kent, 1992; Shumway, 1996; Andrus and Crowe, 2000; McLusky and Elliott, 2004). Previous studies of oyster seasonality in the Southeast used shell length measurements of the impressed odostome, a predatory gastropod found among oyster reefs of the Gulf and Atlantic coasts (Russo, 1991; Fradkin, 2008). This demographic approach (size at season) measures shell lengths as estimates of oyster season of death. Recent studies on oysters in the Southeast have yielded positive results using stable isotope geochemistry (Kirby, 1998; Andrus and Crowe, 2000; Surge, Lohmann and Dettman, 2001). However, morphological seasonal indicators have not been consistently correlated with isotopic profiles in oysters (Andrus and Crowe, 2000; Surge, Lohmann and Dettman, 2001).

Environmental changes are recorded as changes in shell chemistry, shell microstructure, and physical morphology (Rhoads and Lutz, 1980). Certain criteria are required for both visual (structural) and isotopic analyses of modern and archaeological shells. The primary concerns are clear, visual delineation of growth increments, age of the animal, precipitation of CaCO3 in isotopic equilibrium with water, minimal diagenetic effects, and growth throughout the annual temperature range (Shackleton, 1973; Killingley and Berger, 1979; Claassen, 1993).

The primary goal of this research is to determine whether intertidal oysters off the Georgia coast can be used as reliable proxies for estimating season of death in archaeological specimens on St. Catherines Island. Methods used include direct and indirect season of death estimations. Geochemical analysis of carbon and oxygen isotopes from modern and archaeological samples is used as a direct measure of oyster season of death. Shell length measurements of impressed odostomes from modern and archaeological contexts are indirect and are compared to geochemical data. Results on season of capture estimates using odostome shell length are also compared to results obtained by Russo (1991) for modern and archaeological sites. Morphometric analysis of oyster shell shape was applied to modern, historic, and archaeological shells to determine types of habitats from which Archaic oysters were collected (Kent, 1992).

Oyster Seasonality Studies: A Review

Oysters deposit carbonate in concentric rings along their shell margin. The oxygen isotopic composition of skeletal carbonate is primarily influenced by the isotopic composition of the water which is constrained by freshwater input and temperature. Shell carbon is influenced by dissolved inorganic carbon in the source water and metabolic processes (McConaughey and Gillikin, 2008). Therefore, carbonate samples taken from the dorsal to ventral margins of the umbo provide a record of environmental conditions and growth of that organism. Isotope sclerochronology has been extensively used to interpret past environmental conditions for many molluscs (Jones and Quitmyer, 1986; Quitmyer and Jones 2005, see also Andrus, chap. 6, this volume). Determination of season of death for oysters, however, has proved to be a more formidable endeavor. While clams exhibit a clear record of growth in the form of distinct light and dark bands, oysters do not. Oysters are composed primarily of calcite with layers of aragonite occurring on the hinge in the area of ligament attachment and also in the adductor muscle scar (Stenzel, 1694). In cross section, calcitic foliated shell microstructure is interrupted by irregularly sized, chalky shell islands, which have been described as light and dark bands, respectively (see fig. 10.2) (Andrus and Crowe, 2000, Carriker, 1996). However, these bands have not been correlated consistently to environmental causes such as temperature. Stable isotope geochemistry is currently the best method to understand and correlate growth band formation to environmental factors. This section reviews various methods applied in oyster seasonality studies.

Visual Methods

In his seminal work on subtidal oysters from the Chesapeake Bay in Maryland, Kent (1992) uses a method of analysis in which acetate peels magnify growth structures so that winter growth breaks can be distinguished from other breaks on the hinge area (Kennish, 1980). This produces an index that represents a measure of growth since the last growth break or winter season and can be used to retrodict season of death. Custer and Doms (1990) used this method on a modern control population in the Chesapeake Bay area and archaeological specimens in Delmarva Spring. Measurement of the most recent growth is divided by an average of growth over three or more previous years. Herbert and Steponaitis (1998) also used the acetate peel method for modern collections in Maryland and Early and Late Woodland archaeological assemblages with success. Most oyster seasonality studies on modern and archaeological samples in the United States have followed this method. The growth index is the most widely used method but has not been applied to oysters in the southeastern United States. It has been suggested that the growth index method may not be applicable to oysters in the Southeast because the fast growth observed in warmer waters allows oysters to reach edible size at younger ages (Shumway, 1996). Use of the growth index method requires three to five years of growth and oyster populations in the Southeast may reach edible size within two years. Southeastern oysters may even deposit breaks multiple times within a year during all seasons associated with extremes of heat and cold while exposed at low tide (Russo, 1991). The timing of increment formation varies by species and latitude. Kent (1992) notes that the interpretation of growth increments for southern oysters would be reversed—that distinctive breaks would be associated with heat stress. This phenomenon has been reported for hard clams and oysters in the Southeast (Jones and Quitmyer, 1996; Surge, Lohmann, and Goodfriend, 2003). Modern and archaeological oysters from Nueces Bay, on the central Texas coast, do not exhibit this reverse patterning, however. In Nueces Bay, oysters tend to form distinctive winter growth breaks due to water temperatures that average 8° C lower than the Florida Gulf coast (Cox, 1994). Cox (1994) posits that cooler water temperatures produce distinctive winter growth breaks and that this difference in average winter water temperatures may explain the lack of winter growth breaks in southern oyster populations.

Intertidal organisms are adapted to the conditions characteristic of their environments. Oysters are poikilothermic, euryhaline, and ecomorphic and thus able to tolerate variable extremes of temperature and salinity. Their variable morphology and wide geographical range make them highly adaptable to various environments (Van Sickle et al., 1976). It has been suggested that the rate of temperature change is more important for metabolic activities than is the level of temperature (Shumway, 1996). There are few studies on the effects of temperature and salinity on respiration but it has been reported that oyster tissues respond differently to stressors and environmental conditions (McConnaughey and Gillikin, 2008). It is reported that respiration for all tissues increases with warmer temperatures, and decreases with cooler temperatures (Shumway, 1996). However, gill function, the primary organ of respiration, is optimum at 25°–26° C (77–79° F) and stops completely at 5°–7° C (41°–45° F) (Galstoff, 1964; Eble and Scro, 1996). Intertidal oysters in the Southeast may record heat stress while exposed during low tides (Russo, 1991). Oysters are facultative anaerobes capable of closing their valves and reducing O2 consumption to zero if necessary (Hammen, 1969). During the period of time that oysters are exposed at low tide, they may not respire but conserve O2 until immersed again. If these events are recorded in oyster valves, it would be reflected in daily or subdaily tidal growth structures.

Geochemical Methods

Because of the problems associated with visual analysis, methods of determining season of death in southeastern oysters have relied on measurements of organisms associated with oyster populations, like impressed odostomes or stable isotope analysis of oyster shell carbonate. Kirby, Soniat, and Spero (1998) applied stable isotope geochemistry to modern and Pleistocene-aged oysters to reconstruct past estuarine conditions. Using modern oysters from the Mississippi Delta as a proxy for Pleistocene oysters from Chesapeake, Virginia, the authors found that oysters exhibit a seasonal record of water temperature. Additionally, they could establish that external growth structures on the hinge correlated with seasonal temperature changes. This work established some important baselines:

(1) Oysters precipitate shell in isotopic equilibrium with respect to the ambient environment.

(2) Growth increments are formed annually and reflect changes in seasonal water temperature.

(3) For this population, fast growth occurs during the spring/summer months, whereas growth is slowed during winter months.

Andrus and Crowe (2000) established similar baselines for intertidal oysters on Little Egg Island, Georgia. Sampling methods differed from those of Kirby and colleagues because southeastern intertidal oysters do not exhibit similar morphology in the hinge plate as those from the Mississippi Delta. Using laser ablation technology, Andrus and Crowe analyzed carbonate samples from alternating light and dark bands visible in cross section. They found that light bands were formed during warm months and dark bands during cool months. They noted that the primary factor affecting the oxygen isotope composition of oyster shell is temperature.

Surge, Lohmann, and Dettman (2001) studied intertidal oysters from the Blackwater River near Naples, Florida, to establish chemical controls on oyster shell chemistry. They established that all areas of the hinge are suitable for isotopic sampling, including chalky layers, as there was no statistical difference in the carbon or oxygen values. They reported that in these oysters, the chalky layers provide a larger sampling surface. Like Kirby, they found that shells precipitated in isotopic equilibrium with water; however, morphological features did not correlate with season. Also, in Naples samples, oysters exhibit fast growth in the winter, and slow growth during late summer and fall, though Surge, Lohmann, and Dettman (2001) did not confidently attribute the cause of growth cessation to temperature, as this is also the time that spawning occurs. They also found that temperature is more important than salinity in determining the oxygen isotope composition of oyster shell. These differences in methods and results outlined above reinforce the need to acquire historical baseline data of the environment. It is most desirable that historical data are collected as close as possible to the area of study due to regional variability in shell formation in these animals.

Seasonality Determination Using Impressed Odostomes

The impressed odostome is a small predatory gastropod common in oyster beds in the Atlantic and Gulf coasts of the United States (White and Wilson, 1996: 571). These animals attach to the soft tissues of adult and juvenile oysters and feed on body fluids. While these animals may parasitize a number of species, oysters are the primary host species (Powell et al., 1987). Impressed odostomes are reported to have a life span of approximately one year and research conducted over a wide geographical range agrees that spawning occurs continuously with peak reproduction and recruitment in late spring and early summer (Wells, 1959; White, Powell, and Kitting 1984; White, Kitting, and Powell, 1985; Russo, 1991). This initial cohort makes up the majority of the odostome population and members of the cohort increase in size throughout the year until death in spring of the following year. This expected growth pattern will be reflected in measurements of shell length through the year. The short life span, predictable growth rate, and close association with oyster populations make impressed odostomes a suitable proxy for the seasonality of oyster collection. Methods following Russo’s (1991) seminal work on this species are applied to odostomes on St. Catherines Island. Keene (chap. 9, this volume) highlights important points to consider when using this technique. These are primarily related to establishing a sound understanding of growth, reproduction, and behavior of odostomes throughout their geographical range. In addition, the applicability of this method outside of northern Florida is called into question due to problems that arise when Russo’s data are applied to populations outside of this region (Keene, chap. 9, this volume). This study attempts to resolve some of these uncertainties by applying modern proxy data collected on St. Catherines to archaeological odostome shells from St. Catherines Shell Ring.

Oyster habitat on St. Catherines Island

Oysters are located in inland and estuarine salt marshes on both the mainland and coastal sides of St. Catherines Island. These environments differ in that the tidal fluctuations in the estuarine salt marsh average greater than 2 m and occur two times a day (Thomas, 2008: 255–256). The marshes on the mainland side of the island are classified as high marsh (flooded twice monthly by spring tides) and low marsh (flooded twice daily by high tides). In addition, there are interior marshes that experience high tides twice daily but lack freshwater input other than local precipitation (Andrus and Crowe, 2008: 503). Oysters were collected for this study from an interior marsh. The status of St. Catherines Island as a conservation and research island means that no appreciable human pressure has been placed on these animals. As a result, they are generally longer lived than those in regularly harvested shellfisheries. This is an advantage when seeking seasonal patterns over multiple years of growth.

Methods

Stable Isotope Analysis

Approximately 30 modern oysters were hand collected at low tide from Cemetery Road Marsh during the middle of each month from July 2006 to July 2008 to establish a modern analog for comparison. Cemetery Road Marsh is an inland marsh located on the Atlantic side of St. Catherines (fig. 10.1). Specimens were immediately frozen and subsequently transported to the Florida Museum of Natural History for processing and storage. They were hand cleaned with a brush and water and separated into singles from clusters when necessary. Soft tissue was removed manually and shells were dried in a desiccator. Measurements of water temperature and salinity were recorded and water samples taken at the collection site at the time of oyster collection. Salinity levels were measured using a refractometer and temperature was recorded using a digital thermometer. Two well-preserved archaeological specimens were selected from column samples excavated from St. Catherines Shell Ring. Specimens chosen were complete and free of evidence of fouling organisms and predation.

Prior to sampling for isotopic analysis, the left valve of each specimen was radially cross sectioned and mounted on glass slides with JB KWIK Weld and fixed to the sample stage of a Merchantek EO Micromill at the Florida Museum of Natural History stable isotope laboratory. Carbonate samples were drilled in ontogenetic (oldest to youngest) sequence from the calcitic, foliated layers of the bisected surface of the umbo only. Chalky layers were avoided because of the irregularity in size and difficulty of microsampling these areas. Each drill hole measured approximately 50 µm in depth and the holes were 1 mm apart (fig. 10.2). The isotopic analyses were conducted in the light stable isotope mass spectrometry laboratory, Department of Geological Sciences, University of Florida. All samples were analyzed according to standard techniques (Jones and Quitmyer, 1996). All values are reported in standard notation where:

δ18O = [(18O/16O)[sample]/(18O/16O)[standard]-1] × 103 per mil (‰).

The temperature of the water in which the shell carbonate formed was calculated using the paleotemperature equation of Craig (1965) for the temperature-dependent fractionation of calcite in molluscs relative to seawater:

T(°C) = 16.9 – 4.2 (shell δ18O[calcite] – δ[wSMOW]) + 0.13*(δ18O[calcite] – δ[water])2.

Historical temperature data for the two-year collecting period (July 2006–July 2008) were obtained from the National Data Buoy Center station, 41008, located off the coast of Savannah (http://www.ndbc.noaa.gov/station_page.php?station=41008). Temperature measurements taken at the time of collection are not used because of consistent thermometer malfunction which did not allow for accurate temperature readings for some months.

Morphometric Analysis of Shell Shape

Oyster habitat can give insight into interpretations of the carbon isotopic signatures. Oyster shell shape is heavily influenced by the habitat in which it grows. The substrate, density of the oyster bed, the type and number of epibionts, as well as turbidity, salinity, and water depth all influence shell shape (Kent, 1992). The morphometric analysis of oyster shells outlined by Kent (1992) provides a method with which to correlate oyster shell shape to habitat. Calculation of the height-length ratio (HLR) of the left valve is the simplest way to interpret habitat. The HLR is the height of the valve divided by the length (fig. 10.3). Mean HLR values of a sample population provide an accurate estimate of the habitat in which oysters grew. Measurements of oysters from modern, historical, and archaeological sites from the island were measured to determine habitat differences through time. Modern oysters measured were collected from Cemetery Road Marsh (N = 30) and Kings New Ground Marsh (N = 30). Oysters from Hokes Dock (N = 28) are remnants of an early 20th-century oyster boiler. Oysters (N = 481) from St. Catherines Shell Ring were obtained from column samples excavated by the author, during the 2007 field season, from excavation units W82S3 and 789N801E. Meeting House Field (9Li21) is an archaeological site that dates to the Irene cultural period (N = 71).

Shell Length Measurements Using Boonea impressa

Oyster clumps collected monthly from July 2006 to July 2008 (25 months) from the Cemetery Road Marsh site for stable isotope analysis were cleaned in buckets of water and sieved through 1.168 mm geological screens and dried. Archaeological specimens were obtained from the 1⁄16 in. portion of column samples excavated from two units (W83S2 and 789N801E) from St. Catherines Shell Ring. The shell length is described as the measurement from the tip of the apex to the abapical end (fig. 10.4). Shell length measurements were obtained using electronic calipers attached to a desktop computer (see Jones, Quitmyer, and DePratter, chap. 8, this volume). Following Russo (1991), data are presented as a seasonal frequency distribution of length size classes. For purposes of comparison with Russo’s data, his six-season division has been applied to modern data from St. Catherines (table 10.1).

Fig. 10.1. Map showing location of the St. Catherines Shell Ring and oyster collection site (adapted from Thomas 2008).

Fig. 10.2. Radial cross section of oyster showing sampling locations.

Fig. 10.3. Left oyster valve height and length measurements for HLR calculation.

Fig. 10.4. Impressed odostome shell length measurement.

TABLE 10.1. Seasonal Divisions and Sample Sizes for Modern and Archaeological Impressed Odostomes

Season

Months

Sample Size

Spring

May, June

73

Summer

July, August

20

Fall

September, October

1147

Late Fall

October, November

456

Winter

November, December, January

726

Late Winter

February, March, April

309

Excavation Unit

W83S2

196

789N801E

132

Results

Stable Isotope Geochemistry

Figure 10.5 (A–D) shows the δ18O and δ13C values of the two modern and two archaeological shells. Each exhibits a cyclical pattern of shell formation. Low oxygen isotope values indicate warmer temperatures while high values indicate cooler temperatures. All samples were adequate for analysis with the exception of sample 11 in specimen arch-1, which was too small. The δ18O profile from archaeological specimen arch-1 (N = 27) shows a semisinusoidal pattern of five complete cycles with values ranging from –1.35 to 1‰. Similarly, the δ18O profile from archaeological specimen arch-2 (N = 22) shows five complete cycles with values between –1.87 and 1.30‰. Modern oyster CRM-July (N = 26) shows four complete cycles with δ18O values between –1.97 and 1.24‰ and CRM-February (N = 16) shows two complete cycles with δ18O values between –1.18 and 1.38‰.

The calculated temperature for modern oysters correlates well with the water temperature recorded by the buoy at the time of collection with a difference of 4.85° C. Based on a comparison of modern sea surface temperatures with paleotemperatures, both archaeological samples were collected during warm months of the year. Arch-1 was collected during the spring, while arch-2 was collected during the late summer/early autumn (fig. 10.6). All oysters show a pattern of fast growth during the warm months and slowed growth during cool months.

The carbon profiles of the modern and archaeological specimens are markedly different. The carbon profiles in the archaeological specimens track closely with oxygen. Values range from –1.44 to 0.51‰ in arch-1 and –2.03 to 0.60‰ in arch-2, an approximate variation of 2‰. No such pattern exists in the modern specimens where values range from –0.95 to 0.23‰ in CRM 2006 and –1.89 to 2.51‰ in CRM 2007, an approximate variation of 1‰.

Salinity measurements are consistent with a highly saline environment with the exception of two points in September 2007 and January 2008 that are lower than expected (fig. 10.7). All specimens appear to accurately record ambient temperatures throughout the growth period.

Morphometric Analysis of Oyster Shell Shape

The mean and 95% confidence interval of the HLR of oysters from the modern and archaeological sites were calculated for comparison (fig. 10.8). The 95% confidence interval on the mean HLR shows that the difference between modern, historic, and archaeological oysters is statistically significant. Based on HLR measurements, modern collected oysters are classified as channel/reef oysters. As summarized by Kent (1992), these oysters are densely clustered and elongated with an HLR greater than 2.0. They occur in deep channels and are frequently intertidal. This is confirmed by the habitat from which modern oysters were collected. The Cemetery Road Marsh collecting site is intertidal, with oysters densely clustered in soft mud. There was little difference (HLR = 0.01) between the HLR of the oysters in the units 789N801E and W83S2 from St. Catherines Shell Ring, thus the HLR was averaged. Based on the mean HLR, archaeological oyster samples are classified as bed oysters. Bed oysters have an HLR between 1.3 and 2.0 and occur in muddy sand in loose clusters or singly (Kent, 1992).

Shell Length Measurements of Impressed Odostomes

Measurements of modern impressed odostomes from St. Catherines Island follow a growth pattern of increasing shell length from the summer to spring months (fig. 10.9). Peaks in frequency of each size class represent the growth of the initial cohort through time. All size classes are represented in the archaeological samples, therefore all seasons are represented. However, approximately 30% of individuals from unit W83S2 and 27% of individuals from 789N801E correspond to winter/late winter/spring collections. When compared to Russo’s data from Florida, on an annual scale of warm and cool months, both data sets show archaeological oysters were collected during cool months (fig. 10.10).

Fig. 10.5. δ18O and δ13C profiles across oyster specimens from earliest to most recent growth (dorsal to ventral edge of the umbo). Solid lines represent δ18O values, dashed lines represent δ13C values. (A) Modern oyster collected July 2006 from the Cemetery Road Marsh collection site. (B) Modern oyster collected February 2007 from the Cemetery Road Marsh collection site. (C) Archaeological oyster from unit WS83S2 of St. Catherines Shell Ring (arch-1). (D) Archaeological oyster from the St. Catherines Shell Ring unit number 789N801E (arch-2).

Fig. 10.6. Average monthly sea surface temperatures for the National Data Buoy Center Station, 41008 for 2006–2008.

Fig. 10.7. Salinity measurements for July 2006–July 2008 from Cemetery Road Marsh collection site.

Fig. 10.8. A plot of the mean and 95% confidence interval of the shell height-to-length ratio (HLR) of oysters from modern, historic, and archaeological sites (after Kent, 1992).

Fig. 10.9. Frequency distribution of impressed odostomes length size classes from units W83S2 and 789N801E plotted following Russo’s (1991) six-season division.

Fig. 10.10. Comparison of modern odostome collection data with archaeological measurements on an annual scale. A. St. Catherines Island. B. Crescent Beach (Russo, 1991).

Discussion

A record of ambient temperature can be detected chemically in the shells of modern and archaeological oysters from St. Catherines. This result is similar to that of Surge, Lohmann, and Dettman (2001) in their study of oysters from southwest Florida with the exception that seasons of fast and slow growth are reversed. Water temperature is the primary variable controlling isotopic variation in the oyster shell. The observed temperature at the time of collection is consistent with calculated temperatures and oxygen isotope variation in modern shells. The temperature range of all specimens does not exceed the range of modern monthly water temperature averages, which suggests that modern seasonal temperature ranges are similar to those during the Archaic occupation of St. Catherines Shell Ring.

Salinity is an important factor affecting oyster growth, particularly in estuarine environments where salinity can fluctuate rapidly and severely. Of particular concern in estuarine environments is lowered salinity which results in a decrease in the carbon and oxygen isotope ratios, producing a false temperature reading (Mook and Vogel, 1968). Decreased salinity occurs with the introduction of freshwater by rivers, streams, and precipitation in the estuary. Oysters are adapted to a wide range of salinities. Optimal salinity ranges exist though these vary geographically (Van Sickle et al., 1976; McLusky and Elliott, 2004). Lowered salinity in the estuary can invoke a number of physical and physiological responses in different classes of organisms, but for bivalves, particularly sessile ones like oysters, the response is typically to seal themselves within their shell. The ability of oysters to tightly close their shells allows the organism to protect itself from adverse environmental conditions, provided these are temporary (Galstoff, 1964). Upon closing the valves, an oyster can reduce its oxygen consumption until oxygen becomes available again (Hammen, 1969). It is possible that during times of stress such as salinity or temperature extremes, or when exposed to air, oysters respire anaerobically. These events are not likely to be recorded in the microstructure of the shell and therefore would have no bearing on isotopic composition (Schöne, 2008; Lutz and Rhoads, 1977). Andrus and Crowe (2000) suggest that variation in salinity could produce oxygen isotopic variation similar to what is produced by temperature but salinity would have to be seasonally variable. Salinity measurements from the Cemetery Road Marsh collecting site did not show seasonal variation. While oysters may record tidal cycles in their shells, the samples presented here show variation on a larger scale and fluctuations in salinity over tidal cycles are much more fine grained than what is represented in the oxygen isotope profiles for these specimens. The modern samples taken from the oyster bed on St. Catherines indicate a constant, highly saline environment with the exception of measurements made in September 2007 and January 2008. Precipitation records from Sapelo Island, located just south of St. Catherines, indicate that the island received 6.9 cm of rain over the two days prior to the September collection date and 3.4 cm of rain a day before the January collection date (climatological data for Georgia, National Climatic Data Center, 2009). The changes in salinity that occur during the tidal cycles in the estuary are not significant enough in duration or severity to account for the oxygen isotopic variation seen in the modern oyster shells.

Comparing the carbon isotope profiles reveals possible differences in water chemistry between the modern collection site and the archaeological setting. Modern signatures correlate to a stable habitat while the archaeological specimens may be from habitats that experience greater seasonal freshwater mixing. The incorporation of carbonate carbon in the mollusc shell is complicated by dual metabolic and environmental effects and, as such, has not been considered as reliable as oxygen as an environmental proxy (Grossman and Ku, 1986). Recent studies have confirmed that aquatic molluscs generally build shell carbonate from ambient dissolved inorganic carbon and, when carefully interpreted, shell carbonate can be an effective proxy for environmental conditions like salinity and magnitude of freshwater mixing (Fry, 2002; McConnaughey and Gillikin, 2008). It is possible that the carbon signatures in oysters from the shell ring reflect environments that experience greater freshwater input through streams or rivers. Modern oysters were collected from the Atlantic side of the island, which receives little freshwater input except in the form of precipitation (Andrus and Crowe, 2008). This consistently saline environment could account for the weak correlation between carbon and oxygen profiles of modern oysters. Oysters from the St. Catherines Shell Ring, located on the western side of the island, could have come from habitats closer to the ring that experience seasonal differences in freshwater input. The differences in carbon signatures between the modern and archaeological oysters cannot be interpreted without comparative water data from the western side of the island.

Morphometric analysis of shell shape indicates that modern and archaeological oysters lived in different habitats. The difference in shell morphology between the modern and archaeological oysters is supported by the carbon data that may also indicate different habitats. Differences in shell shape may reflect changes in island habitats due to anthropogenic effects. It may not be that Archaic peoples collected oysters from different habitats on the island, but that habitats on St. Catherines have changed through time. Rollins and Thomas (2011: 324–325) suggest that environmental degradation and disease have likely affected the oyster populations on and around St. Catherines but the authors note problems with interpretation of shell size changes in archaeological contexts. Future studies will couple morphometric analysis with additional habitat indicators such as type and frequency of oyster shell predation markers by boring sponges and other organisms.

Shell length measurements of the impressed odostomes indicate cool season collections for archaeological oysters. The combination of geochemical data and odostome measurements indicate year-round oyster collection for the St. Catherines Shell Ring. In comparison to Russo’s data from Florida, the seasonal growth patterns of odostomes from St. Catherines are different, but both populations exhibit a trend of increasing size throughout the year. Additionally, modern winter collections in both data sets are represented by short, broad distributions. Russo explains that this is due to the secondary cohort that widens the size range of the most numerous size classes as the initial cohort dies off. This accounts for the absence of a single peak in the cool season sample. The increase in shell length from summer to spring for the 25-month period supports the hypothesis that a predictable pattern of annual growth exists for odostomes on St. Catherines Island. This hypothesis is challenged by Keene (chap. 9, this volume), who cites the need to better constrain key life history parameters such as variation in shell morphology, growth rate, reproduction, and behavior. While this is certainly true, collecting modern proxy data from environments closest to the archaeological site is essential for gathering such data. Variation in shell morphology, growth rate, and reproductive behavior are expected across geographic ranges and through time. Intraspecific shell shape plasticity associated with environmentally mediated growth patterns is common and documented for many molluscs (Kemp and Bertness, 1983, Martin-Mora et al., 1995; Zieritz, 2010; Marquez and van der Molen, 2011). Furthermore, growth patterns in species occupying the same locality can change over short periods of time (Henry and Cerrato, 2007). Proxy data collected over at least a full year, during all months of the year, are needed to assess growth patterns. Two or more years of collection will capture variation that occurs within a population over time. Once a local pattern of growth has been established, suitability of the proxy can be determined. However, frequent validation of known life history parameters over time and space is necessary if we are to confidently apply proxy species data to past animal populations (Jones, Quitmyer, and Andrus, 2004, Jones, Quitmyer, and DePratter, chap. 8, this volume). Shell length measurements of impressed odostomes from St. Catherines are suitable for determining archaeological season of oyster collection, provided appropriate proxy data are carefully applied.

ConclusionS

Modern and archaeological oysters were evaluated as proxies for environmental conditions and season of oyster harvest on the Georgia coast using direct and indirect methods of season of death estimation. Geochemical records indicate that temperature is the primary variable influencing oxygen isotopic variation in the oyster shell. Although variations in δ18O are consistent with variations in water temperature, more localized historical water chemistry data are needed to estimate seasonal temperature ranges and the range of variation that may occur within individual oysters and oyster beds. Future studies will be based on larger sample sizes and localized historical water temperatures for specimens currently being collected from St. Catherines Island. Analysis of modern oyster samples from the western side of the island, closer to the location of St. Catherines Shell Ring, are needed and may contribute to a better understanding of the carbon signatures. Morphological data show that different habitats were exploited and/or that oyster habitats on St. Catherines have changed considerably over time. Measurements of impressed odostomes indicate year-round collection, with the greatest number of individuals collected in spring. Measurements of this species remain the simplest and most cost-effective method for determining season of oyster collection.

It is possible to estimate the season of death of oysters from archaeological sites with appropriate proxy data. Currently, general estimates of seasonal use of oysters at the St. Catherines Shell Ring cannot be made due to the small sample size of oysters studied, however, future analysis of modern and archaeological specimens from the island will contribute to a better understanding of the role of oysters in the Archaic subsistence economy. Although geochemical methods remain the most effective for determining season of death of oysters, future work should focus on understanding the timing of visible growth structures on the interior umbo and correlating growth structures to geochemical signatures.

CHAPTER 11: What Can Plants and Plant Data Tell Us about Seasonality?

C. Margaret Scarry and Kandace D. Hollenbach

Contradictory descriptions by 16th- and 17th-century Jesuit and Franciscan missionaries, combined with comparatively sparse archaeological investigations, have led to ongoing debates among historians and archaeologists about the degree to which the Guale and their predecessors were seasonally mobile (Thomas, 2008). Were the Guale and other Native American communities living along the Georgia Bight mobile foragers, who visited the coast as part of their seasonal round? Or, were they sedentary central-base foragers—and in later times forager-farmers, who spent much, if not all, of the year on the coast or barrier islands? The American Museum of Natural History’s program of systematic excavations and ecological studies, directed by David Hurst Thomas, on St. Catherines Island, has produced a corpus of data that we can bring to bear on questions relating to the Guale and their ancestors (Thomas, 2008; Reitz et al., 2010). But to understand fully the seasonal activities and mobility patterns of the island’s residents, we need fine-grained data about the plants they collected or cultivated and consumed. Unfortunately, we lack systematic analyses of archaeobotanical data from St. Catherines Island (Thomas, 2008: 978) and there are relatively few detailed analyses from elsewhere along the coast to help fill in the picture. Nonetheless, it is possible to draw on patterns of plant use from the lower Southeast and the broader Georgia Bight to offer some thoughts about how plant data can contribute to understanding seasonal resource use and mobility patterns on St. Catherines Island and elsewhere along the coast.

USING PLANTS IN ANALYSES OF SEASONAL RESOURCE USE AND MOBILITY

Plants have predictable cycles of flowering and fruiting and generally grow in relatively distinct habitats. Thus, plants seem obvious sources of evidence about seasonality and mobility. We can certainly construct charts showing when plants identified in archaeological assemblages were ready for harvest and where gatherers could find those plants. However, inferring seasonal use or mobility patterns from such charts is far from straightforward. Some plant resources must be harvested as soon as they ripen, while others persist into later seasons and may be gathered when time allows. More problematic, most plant foods can be stored for later use. Some remains found in archaeological sites probably derive from plants deposited shortly after they ripened, but other remains may derive from plants processed or consumed long after they were harvested. Thus, ripening dates and habitat preferences by themselves are insufficient to explain people’s seasonal uses of plants or how these relate to settlement and mobility patterns.

Optimal Foraging Models

A more promising approach is to consider the full range of decisions and activities people undertake as they obtain, process, and consume plants and animals. Gatherers do not simply embark on forays to collect whatever resources they happen upon during their day’s walk. Instead they consider which plant foods are ready for harvest or which animal resources are prime for collecting, which patches would be best to visit first, which individuals should join a particular foraging party, and whose efforts might best be spent at camp processing plant and animal foods gathered previously. If we take into account the seasonal and spatial restrictions of plant resources as well as the practices and decisions involved in monitoring, cultivating, harvesting, collecting, processing, cooking, and storing plants—and animals—then we can model the seasonal activities and movements of gatherers.

Optimal foraging models are one avenue for addressing decisions and activities pertaining to resource choices. Models of optimal foraging differ in assumptions, variables, currencies, and computational formulas (Bettinger, 1991; Kaplan and Hill, 1992; Kelly, 1995). With the exception of nuts, plants tend to rank low in diet breadth models that use only calories or simplified return rates for predicting which resources should be targeted. More detailed linear programming models often include micronutrients in their consideration of resource value (Bettinger, 1991: 116–118; Kelly, 1995: 74–78). Models that incorporate micronutrients highlight the importance of fruits and greens because of the vitamins and minerals they contain, and depict relatively diverse diets, which appear to be preferred by most primates (Milton, 1993; Addessi et al., 2010).[1] Such linear programming models, however, require detailed information about nutrient composition that may not be available for many wild foods.

Plant foods fare better in optimal foraging models that separate activities of hunters, presumably men, from those of gatherers, presumably women and children (see Hawkes [1996] and Kelly [1995], for further discussions of the division of labor). These models incorporate assumptions that gatherers target foods that may deliver lower return rates but are predictable. Elston and Zeanah (2002) use this approach to construct diet breadth models for pre-Archaic hunter-gatherers in Railroad Valley, Nevada. Their results suggest that men’s hunting opportunities determined residential mobility, while women’s foraging opportunities determined site locations (Elston and Zeanah, 2002: 115). Closer to our area of interest, Hollenbach (2009: 69–97) applies a central-base foraging model to Late Paleoindian and Early Archaic data from Alabama. Among other things, she demonstrates that plants requiring minimal processing, such as early spring greens and summer fruits, can have high return rates when people collect them near camp but return rates decay rapidly with distance (fig. 11.1). As return rates for large game do not drop precipitously with distance, she argues that site locations and mobility patterns were organized around the seasonal and spatial availability of gathered resources.

Fig. 11.1. Comparison of return rates for mulberries, hickory nuts, and deer (see Hollenbach, 2009, for full discussion).

Operational Chains

Some of the difficulty in applying optimal foraging models, or more broadly, human behavioral ecology models, stems from the problem that relatively little information about the decisions and activities associated with the use of plant resources is available or employed. One way we can remedy this is by constructing operational chains for potential foods. The study of operational chains (chaînes opératoires) was pioneered by Leroi-Gourhan (1964), who argued that operational sequences were deeply embedded in human behavior. Material culture, the organization of space, and subsistence strategies are the products of multiple technical choices (Leroi-Gourhan, 1993; Stark, 1998). Operational chains have been widely used to study the manufacture and use of stone tools and ceramics (e.g., Gosselain, 1998; Lemonier, 1986). A similar approach—though not always referred to as operational chains—is commonly used by archaeobotanists to study crop processing activities in Europe and Asia (Hillman, 1984; Jones, 1984; Fuller, Korisettar, and Venkatasubbaiah, 2001). While operational chains have not been used much to examine the food-related activities of Native Americans, we think they would yield important insights.

In constructing operational chains for subsistence activities, the goal is to identify the choices, activities, resources, tools, and refuse associated with each step in acquiring, processing, and consuming a particular food. Such an exercise can identify pertinent activities and decisions as well as the material signatures they would generate. It can also identify potential scheduling conflicts when decisions must be made to gather or pursue one plant or animal and forego another. Constructing operational chains for all of the food resources available to the inhabitants of St. Catherines Island through time is beyond the scope of this chapter. Here, we discuss some of the most relevant decisions and activities associated with key plant resources used by prehistoric peoples living in the Southeast. We then draw on what archaeobotanical data are available from the Georgia Bight to illustrate some of the seasonal activities and decisions associated with the use of these various plant resources. Table 11.1 sketches out activities, resources, and tools for gathering and processing hickory (Carya sp.) nuts, which were prominent foods for Native Americans in the Southeast. In the following paragraphs, we give a more general description of the considerations that must be addressed to construct operational chains for plants.

We first need a list of potential foods and information about their distribution, abundance, and predictability. We can assemble our list by combining species inventories from archaeological sites with ethnographic or ethnohistoric information about plant use, and knowledge about edible plants available in local fields and forests. People’s use of diverse sets of seemingly low-ranking plants becomes more comprehensible when we take seasonal cycles into account and recognize that choices are based on what food resources are currently available and what can be stored for later use. Other factors, such as a predilection for a varied diet or human social considerations, also certainly affect people’s food selections.

Monitoring/Cultivating: An initial step in building operational chains is to consider the level of human involvement in the growth of each plant. At the simplest level, in the course of their daily activities, gatherers monitor plants from flowering to fruiting. They make their decisions based on knowledge of what is ripe, where alternatives are located, and what will remain available in the future. Gatherers might also tend plants in various ways, including clearing underbrush, pruning, girdling or removing competing trees or plants, coppicing, or even transplanting (Shipek, 1989; Yen, 1989; Fowler, 2008). Acorn (Quercus sp.) and hickory mast (Gardner, 1997; Scarry, 2003) were important resources for southeastern foragers and remained important after crops were added to their repertoire. People gathering firewood, hunting, or simply passing through oak and hickory groves likely kept an eye on the impact of spring frosts, summer droughts, etc. on the flowers and developing nuts. They would know well before fall whether it was a good mast year and which trees and groves were most productive. Several researchers have suggested that people not only monitored nut groves but also managed them to enhance productivity (Munson, 1986; Gardner, 1997; Scarry, 2003).

Intensive agriculture stands at the other end of the spectrum, but cultivation of plants can be described as a continuum (Ingold, 1996; Smith, 2001). People’s investment in cultivated plants may range from simply broadcasting seeds and harvesting those plants that survive through the growing season, to the much more intensive work of preparing beds, sowing seeds individually, weeding, and warding off predators. There are ethnohistoric accounts of southeastern farmers engaging in the full range of cultivation activities: from casually sowing chenopod (Chenopodium berlandieri) on exposed mudflats (Gilmore, 1931; Smith, 1992) to intensively preparing fields for maize (Zea mays) and other crops (Scarry, 2008; Swanton, 1946: 268, 274, 289, 292). The decision to sow on newly exposed ground has little impact on other plant resources. Preparation of more formal plots, however, involves choices about how to allocate time and labor as well as choices about where to locate the gardens, what plant resources will be removed and which, if any, will be allowed to remain. Descriptions of native fields (Bartram, 1928: 57) suggest that people left fruit trees such as plum (Prunus sp.) and persimmon (Diospyros virginiana) standing when they cleared the land. We speculate that they also avoided placing gardens in favored nut groves or at least left prolific trees to continue producing mast. Weeding was also likely selective; people probably tolerated and even tended plants that produced greens, medicines, or fruit (Scarry and Yarnell, 2006).

The investment that gatherers make in tending or cultivating plant foods may vary from year to year, depending on the availability of other foodstuffs. If gatherers expect a poor yield from oak and hickory trees, which only produce sizeable crops every two to five years (Schopmeyer, 1974), they may devote more effort to the preparation and upkeep of garden plots or maize fields. Alternatively, if people anticipate poor crops because of drought, flood, frost or other inclement events, they may monitor and tend wild resources more carefully or plan foraging ventures that take them farther afield than usual.

Harvesting/Collecting: Another consideration is when and for how long the edible portions of plants are available. When we model gatherers’ and farmers’ activities, to the extent possible, our estimates of when foods can be harvested should be based on local data. Besides when they can be collected, it is key to know how long foods stay edible and whether they are attractive to other animals. Knowledge about durability and competition guides gatherers’ decisions about what they must collect immediately and what plants they can delay collecting. Fleshy fruits such as mulberries (Morus rubra) will spoil or be eaten by other animals, whereas dry fruits such as cabbage palm (Sabal palmetto) berries may linger on plants for weeks or months. Sweet acorns are prone to mold and insect infestations and they are favored browse for deer, turkeys, and other wildlife. Bitter acorns and thick-shelled hickories are more rot resistant and will be bypassed by wildlife when sweet acorns are available. Gatherers can defer collection of bitter and thicker-shelled nuts while they harvest those that need immediate attention. Knowledge of ripening periods of plants that are favored by wildlife also is important for hunters because the seasonal movements and locations of game are dependent on the plants they eat (Petruso and Wickens, 1984; Talalay, Keller, and Munson, 1984; Scarry, 2003; Hollenbach, 2009).

We also need to consider how the various seeds, nuts, fruits, and roots were collected and transported (Bettinger, Malhi, and McCarthy, 1997). Do the desired parts remain on trees, shrubs, and stalks or do they drop to the ground? How readily can they be seen and gathered if they are on the ground? Are tools needed for harvesting or can the plant foods be picked, stripped, or uprooted by hand? What kinds of containers are needed for collection and transport? Often there are alternatives to be weighed. For example, Hollenbach (2009: 87) shows that distance affects whether it makes more sense for gatherers to cut chenopod plants, tie them in bundles, and thresh them on return to camp or hand strip the seeds into baskets or bags and not transport the inedible stalks (fig. 11.2). For acorns and hickory nuts, gatherers must consider not only the cost of transporting the nuts in the shell but also loss of “shelf life” if they choose to shell nuts at the grove to reduce transport weight (see below).

Processing/Storage: It is also important to know what processing is required for a given foodstuff. This question is inextricably connected to whether the food will be eaten immediately or stored. If gatherers plan to use the food in the near future, their processing considerations revolve around what needs to be done to make the food edible or palatable and where to perform these activities. Do they eat the food on location or return to camp to cook it? If they decide to return to camp, do gatherers remove inedible portions at the collection site to reduce transport costs or maximize collection time and save “cleaning” for camp?

If gatherers intend to store their harvest, then their decisions about how, when, and where to process the food may be different. Decisions about how to handle foods destined for storage balance considerations about what, if anything, is needed to prevent spoilage, whether the shelf life is longer for a minimally handled or derived product, and whether deferring processing evens workloads or solves scheduling conflicts. Removing nutshells or grain chaff at the collection site may save transport costs but generally reduces the time a food can be kept without spoiling and eliminates the option of deferring labor. For example, to limit mold and insect damage, acorns must be dried or parched before they can be stored, but additional processing to make acorn flour, porridge, or soup can be delayed (Scarry, 2003). Thick-shelled hickory nuts are more impervious to infestations; they can be gathered and stored with little or no processing. Indeed, while the nuts may be placed near a fire to dry, it is better to defer other processing because the shelf life of hickory nut products is significantly shorter than that of unshelled nuts (Scarry, 2003). Once foodstuffs are in storage, there are further decisions to make. Are small quantities of foods removed and processed as they are needed for meals? Or are some episodically processed in bulk generating several weeks’ supply? Households make such decisions based on the labor they have available and on what other activities require attention (Fuller, Korisettar, and Venkatasubbaiah, 2001).

Because they can be stored for extended periods, many plant foods have value beyond their immediate caloric returns. Storage can even out food availability and provide for anticipated lean seasons. As noted above, storage can also even out labor demands and help solve scheduling conflicts. Harvested nuts, grains, and fruits may need to be dried or parched to prevent spoilage, but further processing can often be deferred until there is a lull in other activities or the food is taken out of storage and cooked. Gremillion (2002) notes that starchy and oily seeds such as chenopod, maygrass (Phalaris caroliniana), sunflower (Helianthus annuus), and sumpweed (Iva annua) have relatively low return rates; however, they can be stored with chaff or hulls attached and processed in the winter when there are few foods to gather. She argues that this led not only to the regular incorporation of these foods into southeastern people’s diets but also to the subsequent domestication of these starchy and oily seeded plants. The ability to store plants and defer some labor was an advantage for the people who collected, prepared, and ate those foods.

Processing/Cooking: Finally, we need to consider how foods are cooked. What sorts of vessels or other tools are required? Are there multiple ways a food might be prepared and consumed? Depending on the desired dish, processing activities, cooking equipment, and labor demands may vary. Cracking hickory nuts to extract the meat is a labor-intensive task, which requires a nutting stone, a pick, and patience. Hickory nuts can be processed much more efficiently by pounding, dumping the mix of shell and meat into a vessel of water, boiling, and skimming to extract the oil. Or they can be pounded, sieved to remove the larger pieces of shell, pulverized, and then formed into kenuchee balls, which can be added to soups and stews. While the raw food is the same in all “recipes,” the equipment, labor demands—and quite likely archaeological signatures—vary (Swanton, 1946; Talalay, Keller, and Munson, 1984; Gardner, 1997; Fritz, Drywater Whitekiller, and McIntosh, 2001; Thomas, 2008; Roger Cain, personal commun., 2010).

SEASONAL PLANT USE IN THE GEORGIA BIGHT

Constructing operational chains for multiple food items is a substantial challenge. If we are going to incorporate plant foods more fully into existing models of seasonal subsistence rounds for St. Catherines Island or the broader Georgia Bight, then there is a lot of work to be done. First and foremost, we need robust data about the plants that were collected, cultivated, and consumed. Unfortunately, while there are detailed analyses of animal remains from multiple sites and temporal contexts from St. Catherines Island, the only plant data come from a preliminary report on the mission assemblage (Thomas, 2008: 978). Moreover, there have been far fewer systematic analyses of plant assemblages from elsewhere on the Atlantic coast than from the interior Southeast. Thus, we lack the archaeological basis for assessing the relative importance of various plant foods or for building detailed models of plant use on St. Catherines Island. We can, however, begin by compiling an inventory of plants that have been recovered from sites along the Carolina and Georgia coasts. This gives us a list of plants that might have been used on St. Catherines Island and provides a starting point for thinking about what foods were available to gather or take out of storage over the course of the year and what decisions and tasks were associated with their use.

For this chapter, we have culled presence data from Ruhl’s plant list for Mission-period contexts on St. Catherines Island, with the omission of European-introduced species (Thomas, 2008: 978); from Hollenbach’s analysis of late prehistoric plant remains from Keene’s (2004) excavations of the Grove’s Creek site (9CH71) on Skidaway Island, Georgia (Detwiler and Keene, 2003); and from 19 prehistoric or contact-era sites on the North Carolina coast that are reported in the contract literature (Scarry and Scarry, 1997) and in Kimberly Schaefer’s (2011) dissertation. Most of the sites date after people began to grow maize on the coast, although six of the North Carolina sites also have earlier components. We do not present quantitative analyses or even calculate ubiquity, because only Grove’s Creek and seven of the North Carolina sites have plant assemblages that were systematically collected (using flotation) and fully analyzed. Table 11.2 lists plants identified from the 21 sites.

Even a cursory inspection of table 11.2 is informative. We use the tabulations of species present and the probable collection dates for the various plant foods to sketch out a hypothetical seasonal round of plant-related activities and decisions for forager-farmers living on the lower Atlantic coast or one of the islands.

TABLE 11.1. Decisions, Activities, and Artifacts Associated with Hickory Nut Use (1)

Season

Task

Associated

tools/features

Potential opportunity cost

Application to St. Catherines

Spring

Monitor spring flowering

Negligible if embedded in other activities

Likely embedded in spring forays to gather/collect/trap/fish other resources

Late summer

Monitor nut development

Negligible if embedded in other activities

Likely embedded in summer forays to gather/collect/trap/fish other resources

Early fall

Monitor timing of harvest

Negligible if embedded in other activities

Likely embedded in early fall forays to gather/collect/trap/fish other resources

Fall

Gather hickory nuts

Baskets, poles for knocking nuts from branches

Gather acorns

Hickories are interspersed among oaks on the island both nuts could be gathered simultaneously

Decide size of work group

Collect shellfish

Can shellfish collection be delayed, or performed by others?

Return to logistical camp or home base each night?

Hunt/trap animals that are putting on winter fat

Can hunting/trapping be delayed, or performed by others?

Store hickory nuts

Large storage pits, baskets, bags

Other food procurement tasks

Can storage tasks be performed by a relatively small group?

Store above or below ground?

Other maintenance tasks

Decide to parch first?

Baskets, pots, griddles

Minimal if hearth-dried, other food procurement tasks if parched

Decide near logistical or base camp?

Base camps likely within easy travel distance to tree groves

Decide who controls stores—groups or families?

Storage pits may be located in public or private locales

TABLE 11.1 — (Continued)

Season

Task

Associated

tools/features

Potential opportunity cost

Application to St. Catherines

Fall/winter/

spring

Process hickory nuts

Other food procurement tasks

Stores are likely kept near base camp due to small travel distances on the island

Decide size/ composition of work group?

Other maintenance tasks

Can processing tasks be performed by a relatively small group?

Decide size of batch?

Other foods to eat

Decide tools used for initial cracking

Anvil, hammerstone, basket sieve, large nutshell fragments

Groundstone tools are likely to be recovered and may have residues amenable to lipid analysis

Decide tools used for additional smashing

Mortar, pestle, smaller nutshell fragments

Groundstone tools are likely to be recovered and may have residues amenable to lipid analysis

Decide discard of nutshell, primarily through burning

Carbonized nutshell fragments

Other fuels to burn

Carbonized nutshell is likely to be preserved and recovered through flotation; size of fragments may reflect processing stage

Cook hickory nuts

Other foods to eat

What other foodstuffs (fresh or stored) are available? What is their nutritive/flavor content?

Decide size of batch

Other maintenance tasks

Can cooking tasks be performed by a relatively small group?

Separate nutmeats, or melt into oil

Decide method of heating: hot rock boiling or direct heat

Fire-cracked rock, hearths/cooking pits

Subsurface features are likely to be recognized during excavation but may have been used for various cooking/heating tasks

Decide tools used for cooking

Skin-lined pit, ceramic vessel, scoop to skim nutmeats

Ceramic vessels are likely to be recovered and may have residues amenable to lipid analysis

Discard nutshell, primarily through burning

Carbonized nutshell fragments

Other fuels to burn

Carbonized plant remains are likely to be preserved and recovered through floatation

(1) Sources: Swanton, 1946; Talalay, Keller, and Munson, 1984; Gardner, 1997; Fritz, Drywater Whitekiller, and McIntosh, 2001; Thomas, 2008; Roger Cain, personal commun. 2010.

Spring

Few plant foods are available for collection in the early spring. At this time gatherers likely concentrated on plants with underground storage organs such as arum (Peltandra virginica), duck potato (Sagittaria sp.), and cattail (Typha sp.). Roots and tubers can be collected at virtually anytime, but are best harvested in winter or early spring when they are most tender and starch reserves are high (Scarry, 2003). Despite the fact that preservation of roots and tubers is generally uncommon, we have reports of greenbrier (Smilax sp.) (Thomas, 2008), Indian turnip (Arisaema triphyllum) (Jones, Espenshade, and Kennedy, 1997; Scarry and Scarry, 1997), and an unidentifiable tuber (Detwiler and Keene, 2003) from sites in our inventory. This suggests that roots were important resources for people living along the Carolina and Georgia coasts. Digging roots in the spring requires knowledge about where they can be found even when aboveground (or above water) leaves and vines are absent. It is also labor intensive and potentially uncomfortable when reaching the plants requires wading in cold mud or water. Gatherers’ activities and conversations while digging aquatic or terrestrial roots likely disturbed game, fish, and fowl, making active hunting by the party unproductive. Trips to the marsh side could, however, be combined with setting or checking traps and trotlines for fish, turtles, and crabs as well as with digging clams or other molluscs. Once gathered, some tubers (e.g., duck potato) can be cooked with little processing, while others (e.g., arum) require pounding or grating before they are cooked (Messner, 2011: 20–26). Regardless of the labor, roots would provide a welcome source of carbohydrates at a time when there were few alternatives. In early spring, gatherers also could pick tender greens from plants such as chenopod, purslane (Portulaca oleracea), and poke (Phytolacca americana) that favor open ground and sprout in dormant garden plots and other disturbed soils. Greens eaten raw or stewed provide few calories but are important sources of vitamins and minerals and undoubtedly added welcome variety to meals.

As spring progressed, people would monitor the growth of grasses and the flowering of fruit and nut trees, anticipating and estimating the potentials for future gathering excursions. We have scant evidence for spring-ripening grains such as maygrass, little barley (Hordeum pusillum), or other grasses and sedges. Whether these were much used at coastal sites remains to be seen. If spring grasses were cultivated or gathered, then people must have made time for threshing and parching the grains. Once people began growing maize, beans (Phaseolus vulgaris), and squash (Cucurbita pepo), fields would need to be prepared so that planting could begin by mid-April. As they prepared for sowing and tended their early crops, women could continue to gather greens from volunteer plants.

Summer

During the summer, people would continue to cultivate their crops. Depending on planting dates, maize, beans, and squash ripen from late June into August. Women would pick and cook some of the crops as soon as they were ripe. A significant portion of the crop, however, was likely left until fully mature. Maize would be allowed to dry on the stalk then picked; seed corn would be set aside, and the rest prepared for storage. Husking and shelling the maize would reduce storage bulk but it would increase immediate labor demands and decrease shelf life. Beans would be picked and shelled or the vines might be pulled and threshed to release the seeds. Fleshy squash would need to be cut and dried and the seeds parched or toasted. While waiting for their crops to ripen and after harvesting and preparing them for storage, people could pick and eat or dry a variety of summer-ripening fruit including blackberries (Rubus sp.), blueberries (Vaccinium sp.), mulberries, grapes (Vitis sp.), plums, and maypops (Passiflora incarnata). These have to be gathered as soon as they ripen or they rot or are eaten by animal competitors.

Fall

Late summer and early fall would bring an abundance of plant foods and work. Harvesting and preparing crops would continue into early fall. Chenopod, wild rice (Zizania aquatica), sunflower, and bearsfoot (Smallanthus uvedalius) would offer starchy and oily seeds that could be harvested and stored to be processed and eaten later. Fruits such as elderberry (Sambucus sp.), saw palmetto (Serenoa repens), cabbage palm, wax myrtle (Morella caroliniensis), and black gum (Nyssa sylvatica) would also ripen. Wild rice would need to be gathered before its seeds dropped and were dispersed by water. Elderberries would soon rot or disappear. Chenopod, the palms, wax myrtle, and gum have fruits that are persistent and less attractive to wildlife. Collection of these could probably be deferred.

In mid- to late fall, gatherers’ attention would shift to nut mast with priority in collection and drying given to sweet acorns over thick-shelled hickories. Because of the dietary importance of these nuts, as well as their relatively short period of availability, nut-collecting parties may have been relatively large and included women, children, and men in order to maximize the group’s gains. The size and composition of these task parties may have differed depending on the size of the nut crop that year.

To prevent spoilage, acorns would need to be parched for storage but shelling, leaching, and pounding into flour could be saved for later. Hickory nuts could be set in baskets near the hearth to dry but other processing (see table 11.1) could be deferred. Late fall fruits would include cabbage palm, saw palmetto, and persimmon.

Fig. 11.2. Comparison of return rates for cutting and threshing versus hand-stripping for chenopod and amaranth (see Hollenbach, 2009, for full discussion).

Winter

Winter would bring few new plant foods, though roots, tubers, and persistent seeds and fruits could be gathered. Most attention at this time of year would turn to husking, shelling, cracking, and otherwise processing and cooking stored plant foods.

FINAL THOUGHTS

Much of the seasonal round we describe could fit almost any location in the Southeast. For the most part, we lack qualitative and quantitative data necessary to refine this picture for St. Catherines Island and distinguish the coast from the interior. We can offer several thoughts, however. First, while there is considerable debate about how heavily late prehistoric coastal people relied on crops, maize is consistently present and sometimes abundant at coastal sites. Second, there are several plant foods, notably bearsfoot nutlets and the fruits of black gum, cabbage palm, saw palmetto, and wax myrtle, which are seldom reported for interior sites but are common in coastal assemblages. The dietary role and processing requirements of these plants need attention. Third, our seasonal sketch focuses on plant foods, but gatherers often collect small game, shallow-water fish, and shellfish. During the summer and fall, people would have to weigh the merits of collecting fruit, nuts, turtles, shellfish, etc. When the mulberries or blackberries were ripe did people forgo a trip to the shore or berry patch? Or did they split their work parties and gather both fruit and clams? In this vein, we are intrigued by the data on shellfish collection (see chaps. 7, 8, and 10) that seem to indicate collection of clams and oysters in late fall and early spring when there were few plants to harvest and gatherers may have been collecting tubers from the marsh edges. Last but not least, St. Catherines Island, and quite possibly other island and coastal settings along the Georgia Bight, presents an interesting case for considering central-base foraging patterns. Thomas (2008) has argued that the size of St. Catherines Island and its geological and ecological configuration allowed camps to be located where they would provide access to key terrestrial and aquatic hunting and gathering grounds as well as agricultural soils without the need for seasonal relocation. People could have followed our hypothetical round of plant handling from marshside settlements without making more than brief forays away from camp.

The seasonal round we have sketched is a far cry from what might be possible if we practiced what we preached and examined operational chains and used optimal foraging models to juxtapose the plants and animals targeted by gatherers, gardeners, and hunters. To engage in such an exercise, however, we need additional, detailed, quantified analyses of plant remains, such as Hollenbach’s (Detwiler and Keene, 2003) study of the Grove’s Creek assemblage and Schaefer’s (2011) analyses of coastal North Carolina assemblages.

TABLE 11.2. Plants Identified from Sites along the Georgia and Carolina Coasts

Common name

Taxonomic name

Season available

St. Catherines

Island

Grove’s Creek

North Carolina coast (1)

Crops

Maize

Zea mays

summer

x

x

x

Bean

Phaseolus vulgaris

summer/fall

x

x

x

Squash

Cucurbita pepo

summer/fall

x

x

x

Bottle gourd

Lagenaria siceraria

summer/fall

x

Starchy Seeds

Little barley

Hordeum pusillum

spring/early summer

x

Maygrass

Phalaris caroliniana

spring/early summer

x

x

Vetch

Vicia sp.

summer

x

Wild rice

Zizania aquatica

mid summer/late summer

x

Amaranth

Amaranthus sp.

late summer/fall (2)

x

x

x

Chenopod

Chenopodium sp.

late summer/fall (2)

x

x

x

Knotweed

Polygonum sp.

late summer/fall (2)

x

Wild bean

Strophostyles sp.

late summer/fall

x

x

Sedge family

Cyperaceae

mid summer/fall

x

x

Grass family

Poaceae

x

x

x

Oily Seeds

Bearsfoot

Smallanthus uvedalius

late summer/fall

x

x

Ragweed

Ambrosia sp.

late summer/fall

x

Sumpweed

Iva annua

late summer/fall

x

Sunflower

Helianthus annuus

late summer/fall

x

x

Nuts

Acorn

Quercus sp.

fall

x

x

x

Hickory

Carya sp.

fall

x

x

x

Walnut

Juglans nigra

fall

x

Fruits

Blackberry

Rubus sp.

summer

x

x

Blueberry

Vaccinium sp.

summer

x

Creeping cucumber

Melothria pendula

summer

x

Grape

Vitis sp.

summer

x

x

x

Maypops

Passiflora incarnata

summer

x

x

x

Mulberry

Morus sp.

summer

x

Plum/cherry

Prunus sp.

summer

x

Elderberry

Sambucus sp.

late summer/fall

x

Prickly pear

Opuntia sp.

late summer/fall

x

Wax myrtle

Morella caroliniensis

late summer/fall

x

x

TABLE 11.2 — (Continued)

Common name

Taxonomic name

Season available

St. Catherines

Island

Grove’s Creek

North Carolina coast (1)

Black gum

Nyssa sylvatica

fall

x

x

Cabbage palm

Sabal palmetto

fall

x

Saw palmetto

Serenoa repens

fall

x

Palm family

Arecaceae

fall

x

Persimmon

Diospyros virginiana

fall

x

Dogwood

Cornus sp.

fall

x

Sumac

Rhus sp.

fall

x

x

Yaupon holly

Ilex vomitoria

fall

x

Hackberry

Celtis sp.

fall/winter

x

x

Roots and Tubers

Indian turnip

Arisaema triphyllum

all year (3)

x

Greenbrier

Smilax sp.

all year (3)

x

Tuber or root

all year (3)

x

Greens and Miscellaneous

Bedstraw

Galium sp.

x

x

Carpetweed

Molluga sp.

x

Copperleaf

Acalypha sp.

x

x

Gromwell

Lithospermum sp.

x

Morning glory

Ipomoea/Convolvulus sp.

x

x

Mustard

Brassica sp.

x

x

Pokewee

Phytolacca americana

x

x

x

Purslane

Portulaca sp.

x

x

Spurge

Euphorbia sp.

x

x

Stargrass

Hypoxis sp.

x

(1)Presence data derived from 19 sites along the North Carolina coast.

(2)Season indicated is for ripe seeds. Greens would be available in spring/summer.

(3)Available all year but highest starch content is in winter/early spring.

(4)Sources: Abbott et al., 1999; Crites, 1999; Detwiler and Scarry, 1999; Gardner, 1984, 1990; Glazier, 1987; Green, 1984, 1986; Jones, Espenshade, and Kennedy, 1997; Loftfield, 1979; Marshall, 1986; Payne and Dahlin, 1987; Scarry and Scarry, 1997; Schaefer, 2011.

CHAPTER 12: Making a Case for Coastal Subsistence Seasonality

Gregory A. Waselkov[2]

This chapter represents for me something of a rebirth as a coastal archaeologist. After dissertation research on a Potomac River oyster midden and publication of a worldwide review of shellfish gathering and shell midden archaeology (Waselkov, 1987), my career took a decades-long detour into the ethnohistory of southeastern North America and the archaeology of French colonists and historic Creek Indians. When an opportunity arose a few years ago to do some developer-funded investigations of Woodland shell middens on the Alabama coast, I felt akin to Rip van Winkle reawakening to a world changed greatly in the interim. While there are surely drawbacks to such a circuitous career path, my return after a long preoccupation elsewhere in the discipline has allowed me to see coastal archaeology with fresh eyes and envision some potentially fruitful paths forward. The invitation to join the Caldwell V conference on seasonality, where participants were immersed for a few days amid one of the most productive and innovative coastal archaeological projects underway anywhere in the world, offered the perfect venue for introspection.

Understanding seasonality seems, more than ever, to be essential to unraveling the rhythms and rationales of lives lived in coastal landscapes. More than an end in itself, though, seasonality is a portal through which we can grapple with questions of residential mobility, exploitative strategies, and many other facets of human existence along the world’s estuaries. A good place to begin, therefore, is with a glance back at the shifting significance placed on seasonality by archaeologists concerned with coastal settings.

In the wake of the influential (and controversial) “Man the Hunter” symposium held in 1966 at the University of Chicago, Lee and DeVore famously offered “two basic assumptions about hunters and gatherers: (1) they live in small groups and (2) they move around a lot” (Lee and DeVore, 1968: 11). Both generalizations provoked criticism and an extensive literature now documents great variability in group size and mobility observed ethnographically among hunter-gatherers (Lee and Daly, 1999). Archaeologists participated in the ensuing debate in two ways, by developing the theoretical means to distinguish various kinds of residential mobility in the archaeological record and by recognizing that the archaeological record contains evidence for approaches to mobility unobserved in the modern world (Yesner, 1980).

Binford (1980, 1990) contributed substantially by contrasting the residential mobility of foragers who move as a group to their resources with the logistical mobility of collectors who exploit resources as individuals or specially organized task groups. He conceived of logistical and residential variability not “as opposing principles … but as organizational alternatives which may be employed in varying mixes in different settings” (Binford, 1980: 19). Nevertheless, many archaeologists have employed the collector/forager concepts as typological opposites or two extremes on a continuum without recognizing the multidimensional nature of the organizational possibilities they imply. Similarly Kelly (1992: 50, 60) has criticized archaeologists for the tendency to think in terms of a single scale of mobility leading toward sedentism that conflates the independent variables of individual and group mobilities (each with its own factors of age, gender, kin relations, and abilities), territorial shifts, and migrations. Among the many dimensions of mobility, he enumerates “seasonal movement of the residential base camp, movement of individuals around and between residences, movement of a group’s yearly range or aggregation site ..., and permanence of facilities such as houses and fish weirs” (Kelly, 1995: 148–149; cf. Builth, 2006: 14–15).

Ames has explored the transformative role of watercraft in aquatic resource exploitation, particularly the possibilities for food production by easing acquisition and transport, as in opening new offshore habitats to exploitation and expediting collection of large amounts of small-sized taxa, which might not be a cost-effective strategy without boats even over short distances (Winterhalder, 2001; Ames, 2002: 34, 47). Selective resource exploitation assisted by watercraft could, of course, have seasonal mobility implications by enabling access to widespread habitats through broad dispersal of task groups or village movement. In some watery environments, canoes may at times have so transformed mobility that they became the residence, the ultimate in mobile central-place foraging.

A number of researchers have noted that gender and age distinctions may be reflected in archaeological food remains at coastal sites. In modern societies where shellfishing is conducted at a domestic nonindustrial scale, women and children are the most active shellfish gatherers (Meehan, 1982; Waselkov, 1987: 96–99; Claassen, 1998: 175–182; Klein, 1999; Bird and Bliege Bird, 2000). Ethnographic studies have repeatedly documented such age and gender disparities in foraging and collecting emphasis, with important dietary implications (particularly in protein and fat contributions to diet) for segments of society with limited access to hunted sources of meat (Bigalke, 1973; Meehan, 1982; de Boer, Pereira, and Guissamule, 2000; Thomas, 2002; Bird, Bliege Bird, and Richardson, 2004; cf. Voorhies, 2004: 129–141, for a nondomestic example). Precisely how this generalization translates to specific seasonal mobility patterns remains an open question for archaeologists, but one that should be considered in the development of seasonality models.

Coastal seasonality is playing an important role in reevaluations of the origins of cultural complexity. In recent decades, archaeologists have found early evidence of complexity in the relatively sedentary village sites of hunter-gatherers who occupied areas with abundant resources. In most parts of the world, it is now apparent, sedentism and cultural complexity preceded plant and animal domestication and in fact may have been preconditions for serious reliance upon domesticates. Not too many years ago, archaeologists considered coastal resources less reliable and less abundant than terrestrial and riverine resources (Cohen, 1977; Osborn, 1977), but that erroneous attitude was based on misunderstandings of estuarine environments, which are some of the most productive on earth (Rowley-Conwy, 1983, 1998; Brown, 1985; Marquardt, 1996; Costanza et al., 1997; Erlandson, 2001). Studies of cultural complexity in coastal locations are hampered to some extent by Holocene marine transgressions that inundated early coastlines. But worldwide evidence is revealing how substantial populations exploited estuarine resources, in some cases creating large sites interpreted as permanent, year-round villages of coastal hunter-gatherers organized in complex societies (Russo and Quitmyer, 1996; Russo, 1998; Keene, 2004; Thompson and Andrus, in press). Archaeologists need to understand how coastal strategies differed from interior strategies, which in so many instances led to reliance on agriculture. Brian Hayden concisely states the dilemma:

One of the major conundrums of the domestication problem … is why domestication did not occur in certain neighboring regions or areas that seem to have been just as well endowed and as rich and environmentally variable as the initial hearths of domestication. In the eastern United States, for example, while people in the Ohio and neighboring valleys actively domesticated a number of species, nothing appears to have happened around the Louisiana floodplain or the Gulf Coast region until the introduction of efficient maize cultivation thousands of years later. California provides another example of a problem area with many diverse habitats and great resource variability. Australia is a problem area of even greater magnitude…. (Hayden, 1995: 297)

Archaeologists working along coastlines are rethinking this issue. In California, for instance, Kroeber’s long-accepted view, that the natural complementary bounties of oak groves and coast made domesticates unnecessary, is being replaced by a more realistic grasp of local environmental uncertainties and a better appreciation of settlement and subsistence strategies that relied on diversification rather than specialization (Kroeber, 1925: 919–926; Raab, 1996; Glassow, 1997; Luby, Drescher, and Lightfoot, 2006; Jones et al., 2008; Lightfoot and Parrish, 2009). Builth (2006) argues for the development of social complexity along the temperate south coast of Australia based on evidence of landscape management and the development of a storage economy and trade in wild foods. Cases like these begin to dismantle long-standing assumptions about the rise of social complexity and challenge the presumed exceptionalism of California and Australia as ethnographic oddities, places where people inexplicably rejected agriculture and the monumentality that often followed the rise of social complexity elsewhere in the world.

I suggest that coastal regions routinely supported nonagricultural forms of resource use and permitted different trajectories of social complexity than are documented in noncoastal regions (also see Hayden, 1990; Jochim, 2006). One of Binford’s principal conclusions in Constructing Frames of Reference, his massive analysis of ethnographically documented hunter-gatherer behavior, is his observation that subsistence intensification by hunter-gatherers eventually leads to one of two outcomes: dependence on aquatic resources or dependence on plant domesticates (Binford, 2001: 201, 357, 368, 443–444). In the absence of evidence for agriculture, archaeologists must refocus their energies on interpreting those plant and animal remains that reflect not only the changing targets of use, but the changing seasonalities of exploitation and settlement. Hayden’s comment above, that “nothing appears to have happened around the Louisiana floodplain or the Gulf Coast region until the introduction of efficient maize cultivation thousands of years later,” of course reflects our collective ignorance of what did happen in those areas during several thousand years of increasing population density and social complexity. We now know the earliest mound ceremonialism in North America appeared in the Mississippi floodplain around 5300 b.p. (Saunders et al., 1997), and the northern Gulf supported a series of vibrant nonagricultural societies culminating in Weeden Island, which disappeared coincident with the expansion of Mississippian maize farmers around a.d. 1250 (Brown, 2003). These thousands of years of nonagricultural existence were not insignificant footnotes to the rise of agriculture. Rather, they represent remarkably effective alternatives to the reliance on domesticates practiced by their neighbors and constitute an important but neglected part of the human past that we need to understand on its own terms.

But my task here is to focus on the problems facing archaeologists who wish to understand coastal seasonality. Seasonality of resource use and residential patterns is fundamental to many significant human behaviors. Managing or accommodating seasonal aspects of plant and animal physiology and habits underlies such diverse behaviors as rites of passage, calendrical rituals, political and economic organizations, harvest cycles, architectural designs, settlement patterns, and the density and size of human populations. Seasonality is fundamental to these phenomena because most of the organisms important for human life respond to cycles of temperature, moisture, and other variables that define seasons.

Unraveling the complexities of seasonality using archaeological data has proven extremely difficult. It is not uncommon for modern studies to extrapolate overall seasonality of resource use for entire sites from evidence provided by one or two species (each typically represented by a handful of specimens). In simplest form, seasonal preferences of species present in a sample are cited to establish which seasons are represented in the assemblage and which are not, thereby linking seasonal behavior of plants and animals with human residential patterns. This approach to deriving seasonality and reconstructing environments relies on analogy to modern species physiology and behavior, and on a further (doubtful) assumption, that climates, ecosystems, and organisms have remained unchanged throughout the Holocene. This approach fails to capture the complexity, diversity, and inherent flexibility of organisms, including people, on a daily, seasonal, annual, and long-term basis. Nonetheless, this remains the dominant archaeological method to assess season of site occupation in many parts of the world.

In addition to problems inherent in using modern ecological analogies, other problems exist in assessing seasonality at coastal archaeological sites using species presence/absence, quantified or not. In those cases where more than one site is studied, neither site locations nor artifact types provide the precision needed to verify or refute the presence of an asynchronous residential pattern due to seasonal availability of resources on a regional scale (e.g., Thomas, 2008). Radiocarbon dating has not yet provided fine enough temporal control to establish two or more sites as part of a seasonal round, or the contemporaneity of complementary special function sites, or the sequential reuse of a site on a year-to-year basis. (However, see Kennett and Culleton, chap. 2, this volume, for a possible resolution of the problem.)

Faunal evidence is equally challenging. Many animals are (and were) available throughout the year at different places along subtropical and tropical coasts. Although they may move, reproduce, and grow seasonally, the broad behavioral and physiological patterns visible in modern species are often unclear from archaeological taxonomic identifications, element distributions, measurements, ages at sexual maturity, and seasons of death, particularly when the ancient prey lived in different environmental conditions or different climatic regimes than exist currently. Ethnobotanists have similar problems. It does not help that fruits and grains have “seasons” when they are ripe, because in tropical and subtropical environments these seasons are fluid and can only be broadly defined. Both zooarchaeologists and ethnobotanists argue, too, that identified taxa could have been caught or collected in one season and stored for later use, or processed elsewhere in such a way that no evidence of their use reached the site being studied.

In sum, after more than a century of archaeological effort, we cannot yet prove that people lived at two different sites within the same year, let alone parse out the precise season in which each settlement was occupied, for what purpose, and by how many people. However, our inability to replicate the kind of observations made by ethnologists does not mean that archaeologists cannot address the seasonal nature of foraging behavior in the past. We do need to face up to current limitations of our analytical procedures, reassess the possibilities of our data, and consider where we can make better progress.

It is increasingly obvious that multiple lines of evidence (e.g., from radiocarbon dating, isotopic profiles, zooarchaeology, paleoethnobotany) ought to be pursued with equal rigor on a variety of sites that might have been part of a seasonal round, exchange network, kin group, or some other economic or social unit in order to assess variability in coastal settlement patterns. Ideally these methods ought to be performed in tandem at coastal and inland sites to explore entire settlement patterns and understand how sites of different sizes and functions in different locations fit into the overall landscape. In practical terms, however, as expressed by Bar-Yosef and Rocek (1995: 2), “the likelihood of recovering all of the sites in a settlement round is vanishingly small ... we must give up the idea of reconstructing the entire settlement pattern” of any ancient society. I share their skepticism on that score, given current limits of analytical methods, disparities in faunal preservation often observed between coastal and inland sites, and losses to modern development that disproportionately impact the world’s coastal sites. Yet I maintain that we should apply our best analytical procedures more rigorously and more broadly to learn, as best we can, how patterns of subsistence and residential mobility changed over time.

You may take issue with my assessment of the progress archaeologists have made in determining seasonality of site occupancy, especially in light of recent widespread advances in the analysis of growth structures in shellfishes, fishes, and mammals. In fact, I am heartened that archaeologists are developing ever more powerful tools to establish seasonality of capture, and many of the Caldwell V conference participants have contributed to this effort (e.g., Quitmyer, Jones, and Arnold, 1997; Waselkov et al., 1998; Andrus and Crowe, 2000, 2008; Quitmyer, Jones, and Andrus, 2005; Reitz, Andrus, and Sandweiss, 2008; Thomas, 2008; Culleton, Kennett, and Jones, 2009). But most of this progress has been species specific. The biology of each target species is complex enough that the various techniques (e.g., those based on periodic changes in ontogenetic growth structures, oxygen isotopic profiles, population availability due to migrations) have had to be carefully crafted and tested in multiple locations to demonstrate their efficacy. Consequently, few archaeologists have applied more than one or two of these new analytical techniques to an assemblage, and they typically examine very few specimens per site. We, as a profession, have so far missed the opportunity to gather a broad range of evidence for complex seasonal activities undertaken by people who could plan and carry out more than one task at a time, different tasks in rapid succession, and tasks that changed in response not only to seasonal variation but to environmental fluctuations at longer time scales.

I will mention just two areas of inquiry I think are amenable to immediate improvement: (1) seasonality modeling that considers evidence of ontogenetic movement (that is, during the lifetime of an individual animal) between habitats; and (2) increasing resolution and confidence in seasonality estimates by statistical analysis of oxygen isotope and other temperature proxies.

Habitat Analysis

While oxygen isotope analysis has gained wide acceptance as a reliable means of determining season of capture for animals with calcium carbonate structures, the potential for stable isotope and elemental analyses to provide information on location of capture is barely explored, although this is obviously an aspect of season of exploitation (see Ishimaru et al., 2006; Lynch, Hamilton, and Hedges, 2008). Biologists are actively pursuing this line of inquiry for their own purposes (such as tracking migrations or tracing habitat environmental changes; see Hobson, 1999), and some of their findings and procedures have relevance and applicability to archaeology. Though not necessarily aimed squarely at seasonal questions, determining habitat of acquisition can inform seasonal interpretations in many contexts. Archaeological application is still experimental, but I think entirely feasible, as I’ve tried to demonstrate with a small pilot study focusing on white-tailed deer that examines carbon and nitrogen isotope analysis of bone collagen.

My original intent was to seek evidence of transport of deer elements between inland and coastal locations. Suspicion that such transport occurred was raised by the presence at the Late Woodland Bayou St. John site on the Alabama coast of hundreds of tools, mostly awls and spatulas, made almost exclusively from deer metapodials (Price and Waselkov, 2009). Analysis of all deer bones, worked and unworked, from Bayou St. John revealed disproportionate numbers of metapodials compared to other skeletal parts. Since movement of subsistence remains has important implications for the interpretation of site subsistence, seasonality of occupation, and regional economies, I devised an experiment to distinguish bones of coastal deer from bones of deer hunted at inland locations.

Analysis of stable isotope ratios of carbon and nitrogen in organic remains is based on their roles in two major biogeochemical cycles, the carbon cycle and the nitrogen cycle. A great many biological and chemical processes lead to variation in the relative proportions of these isotopes (for the basic science, see Hedges, Stevens, and Richards, 2004, 2005; Dawson and Siegwolf, 2007; Ferrio et al., 2007; Pollard et al., 2007: 176–189; Crawford, McDonald, and Bearhop, 2008). In particular, differences in human and animal bone collagen ratios of 12C to 13C (δ13C) and 14N to 15N (δ15N) have been interpreted as dietary indicators (DeNiro, 1985; Bocherens et al., 1999; Evershed et al., 2007; Goffer, 2007: 307–309; Koch, 2007). Both are closely tied to trophic level, so, for instance, carnivores are enriched in 15N compared to their herbivore prey. Terrestrial herbivores from different habitats are frequently distinguishable on the basis of δ13C and δ15N values, which fluctuate in the plants upon which they feed. Archaeologists have mostly used this approach to document the importance of domesticates, particularly maize, in the diets of humans (or, indirectly, in their dogs; White et al., 2001), but there are other potential applications.

Five deer bone samples—three from the coastal Bayou St. John site and two from the Late Woodland Corps site situated inland in the Mobile-Tensaw delta—were submitted to Beta Analytic for collagen extraction and δ13C and δ15N analysis using procedures (Brown et al., 1988) standard for AMS radiocarbon dating of bone. The results (fig. 12.1) indicate 13C depletion and 15N enrichment in bones from the inland site compared to two bones from the coastal site. A third bone from the coastal site isotopically resembles the inland bones, suggesting transport of some deer parts to the coast, as anticipated. With additional testing, this approach may prove a valuable analytical tool for investigating the transport or exchange of subsistence materials between settlements, data that might otherwise be interpreted as evidence for seasonal task group activity.

A second approach to habitat analysis, applicable to shellfish valves and fish otoliths, involves elemental and isotopic analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to obtain information on ontogenetic habitat changes of individual mobile fish (with their own seasonality implications) and to identify exploited habitats of mobile and sessile shellfish. Elements of interest include Ca, Mn, Sr, Ba, Pb, the lanthanide rare earths, Th, and U. Oxygen and carbon isotopes have also been used for habitat studies.

Multiple elemental and isotopic analyses of shellfish valves primarily reveal data on habitat of capture. Archaeologists previously have had little access to this kind of information. For instance, surface features and valve shape (“ecomorphism”) of oysters have traditionally been regarded as indicative of habitat (i.e., bed, sand bottom, channel, and reef) (Galtsoff, 1964: 21–32; Kent, 1988: 28–38), but these can be ambiguous, and most species do not vary by habitat in simple morphological ways. Some biological research suggests that Ba/Ca profiles may reveal differences in environment of origin, and δ18O analyzed for salinity may prove enlightening because salinity in estuaries should correlate with distance from passes to open water (Surge, Lohmann, and Dettman, 2001; Barats et al., 2009; Hobson et al., 2009).

Analysis of fish otoliths is likely to lead in unexpected directions. Within the last half century, biologists have built ever more complex fish life histories documenting migrations between shallow coastal estuarine habitats and open waters. In my research universe on the northern coast of the Gulf of Mexico, Livingston (1975, 1982, 1985) pioneered studies of estuaries, which he found to be not only geologically unstable, but highly dynamic in terms of seasonal and annual variations in temperature, salinity, nutrient flow, and grassbed compositions. Most fish become increasingly specialized in their food habits as they develop in estuarine nurseries, migrate to the open gulf, and return to the estuaries as adults. Livingston showed a progression of species entering and leaving estuaries through the year, and others have noted seasonal habitat preferences of different species (Rozas and Zimmerman, 2000; Rozas and Minello, 2001).

In recent years biologists have explored stable isotope relationships to these variables and have found, for instance, that δ15N and δ87Sr are enriched in fish moving from estuarine to deep water habitats, and δ13C is enriched in seagrass habitats (Hobson, 1999: 320–321; Nagelkerken and van der Velde, 2004). Thus a chemical signature record of an animal’s habitat changes is recorded in otoliths. A combination of light-stable isotope analysis (δ13C, δ15N, δ18O) and trace element analysis is likely to reveal information about habitats preferred for exploitation. Identifying collection habitats, and not ontogenetic movements, is typically the focus of archaeologists, since they relate most directly to human residential mobility. But archaeological data on changes in fish species habitat preferences may correlate with data being gathered by marine biologists (see France, 1995; Hanson, Koenig, and Zdanowicz, 2004; Dorval et al., 2004; Kennedy et al., 2005; Martin and Thorrold, 2005; Surge and Walker, 2005; Comyns et al., 2008; Fodrie and Herzka, 2008; Fodrie et al., 2010; cf. Chittaro et al., 2005, 2006). In collaboration with Betsy Reitz and Fred Andrus, I have proposed a trial study of hardhead catfish and spotted seatrout otoliths. Catfish otolith chemistry is expected to reflect a limited habitat range of high-salinity mud/sand flats and channels, while seatrout could have been collected from a wider range of seagrass, oyster reef, channel, and salt-marsh habitats. In this sort of study, oxygen isotope analysis will enable us to calibrate the seasonal timing of habitat exploitation (reflected in other chemical signatures). The two analytical methods work in concert, which makes this a very powerful interpretive approach. As an ancillary benefit, gaining a means of analyzing shellfish and fish remains for habitat of capture should finally enable archaeologists to document and quantify dependency on canoe transport.

Fig. 12.1. Results of a trial carbon and nitrogen isotope analysis of deer metapodial bone collagen samples from two Late Woodland sites, the coastal Bayou St. John site (1BA21) and the inland Corps site (1CK56).

Statistical Analysis

Climatologists (e.g., Grimes et al., 2003) have suggested a need to apply statistical procedures to seasonality data, something both biologists and archaeologists have been reluctant to do. δ18O data profiles of individual mollusc valves and otoliths are generally interpreted individually and very conservatively by attribution to broad seasonal divisions: spring, summer, fall, winter. I suspect this hesitancy to employ statistics is a consequence of the very small sample sizes available until recently in most seasonality studies. In the past it has not been uncommon for seasonality interpretations to be based on temperature proxy curves obtained from samples of one, two, or three shells per stratum or even per site. As our analytical methods mature and we acquire suites of data from larger archaeological samples, we are now beginning to see that temperature data profiles for individuals of the same species differ in ways that at least in part reflect natural variation around a mean with a calculable standard deviation. Earlier studies that relied on a few shells tended to interpret seasonality of harvest so conservatively because the natural variation was not well understood. Apparent differences in paleotemperatures at harvest were interpreted as evidence of harvest across seasons. But modern control studies of shellfish harvested monthly at many locations now thoroughly document how a single day’s harvest can be represented by a substantial range in δ18O values. Clearly we need to refine our seasonality interpretations in light of larger-scale modern control and archaeological studies, to narrow our seasonality estimates for specific collection events rather than continue to follow an overly conservative approach that yields three-month or six-month interpretations of archaeological deposits that, on the basis of other evidence, must have accumulated much more rapidly.

It is worth recalling that the preferred archaeological contexts for seasonality sampling were identified decades ago (Koike, 1979; Deith, 1986: 69; Waselkov, 1987: 142–144; Stein, 1992: 77; Stein, Deo, and Phillips, 2003; Claassen, 1998: 152). Gorski (2005) defined the smallest unit of analysis as the microstratum, the smallest visible “natural” stratum (a pocket or lens of midden). In deposits consisting largely of mollusc valves these are often interpreted as single episodes of cultural deposition—the contents of a fish boil or debris from a single shellfish roast or some other processing event, discarded as primary refuse and forming a discrete feature representing a moment in time. These micro contexts rightly turn our attention from a site as a generalized whole to the individual activities that, multiplied a thousand fold, created a site’s deposits. By focusing analysis on micro contexts, they can give us meaningful insights on real behavior and help us move away from the deceptively simple (and simply deceptive) generalized “behavior” we think we see when our unit of seasonality analysis is an accreted midden or an entire site.

By comparison to modern control studies, we should be able (simplifying greatly) to calculate probability values that correlate increments of the δ18O proxy curve to water temperature values. When we compare probability curves between species, the problem becomes more complex. However, we have an archaeological precedent for such an analysis in the method used to calibrate radiocarbon years to calendar years, which is an application of Bayesian statistical analysis (see Buck, Litton, and Smith, 1992; Buck, Cavanagh, and Litton, 1996; Buck and Millard, 2004a; Whittle and Bayliss, 2007). I have only begun to develop this idea, but Bayesian statistics offer a way to combine evidences of seasonality from our multiproxy studies. The protocol of monthly interval sampling followed in the most exacting oxygen isotope analyses allows conversion to rank-order data suitable for modeling (Heuzé and Braga, 2008). A very early application of Bayesian analysis to season of capture questions directed at fish otoliths (English and Freeman, 1981) demonstrates the appropriateness of the approach, but modern computer modeling of micromilled samples promises much finer seasonal resolution with an estimate of associated uncertainties (cf. Parnell et al., 2008).

In sum, we need thorough investigations of subsistence seasonality in specific locales occupied for limited periods of time to test the limits of our current range of analytical skills. Specifically, we need to apply traditional zooarchaeological methods, extensive oxygen isotope analyses (correlated by statistical analysis), incremental analysis, morphometrics, and related approaches to well-dated assemblages. Our goal should be to apply and refine the best techniques currently available to adequately sample and precisely define and model with confidence the seasonal component of coastal settlements, providing a platform upon which subsequent studies of other cultural variables and other environmental processes can be built.

CHAPTER 13: Discussion

Elizabeth S. Wing

The Fifth Caldwell Conference was held in a gorgeous setting free from commercial distractions, making it a pleasant and intellectually stimulating experience. The intent of the conference was to provide a forum for discussion of different aspects of the archaeological research being conducted on the island and directed by David Hurst Thomas over many years. The research has involved a large number of students and archaeologists committed to detailed longitudinal studies of the full array of materials excavated from archaeological sites on the island. St. Catherines Island was occupied for 5000 years, from the two Late Archaic period shell rings right up to the 17th-century Mission Santa Catalina de Guale and then into the plantation era. Archaeological deposits on this coastal island provide evidence for changing environmental conditions and successive cultures of people who inhabited it.

The focus of this year’s conference was seasonality and mobility along the Georgia Bight. To be most effective in approaching these issues the research requires a multidisciplinary approach marshalling the specialized disciplines of biologists, zooarchaeologists, archaeobotanists, geochemists, sclerochronologists, and, of course, archaeologists. Such research requires detailed study of the local conditions of the island and its surrounding waters as well as year-long studies of seasonal changes in plant and animal growth to provide baseline data for interpreting evidence of seasonal changes seen in the archaeological remains of animals. The baseline studies would include, but not be limited to, shellfish incremental growth patterns and sizes, fish species compositional changes throughout the year, annual growth and reproductive cycles of game animals, and fruiting of plants. These present-day observations will, of course, show fluctuations from year to year in response to environmental changes such as temperature and rainfall variation, much as they did in the past. Consequently, it may not be possible to estimate seasons of harvest with great precision. However, the more we know about variability in life histories of the plants and animals used by people, the better our understanding of human adaptations to the dynamic coastal setting.

People are generally flexible in adapting to changes in resource availability (Reitz, Quitmyer, and Marrinan, 2009). Despite environmental variations, “data demonstrate the antiquity, flexibility, and richness of a well-established dynamic coastal fishing and hunting tradition in the southern Georgia Bight that existed for millennia before the 17th century” (Reitz et al., 2010: 76). The persistence of the Guale tradition is demonstrated by faunal assemblages deposited during the Mission period indicating that the “Spaniards altered their diet toward local Guale subsistence patterns far more than Guale members of the community altered theirs to conform with Spanish practices.” (Reitz et al., 2010: 131).

Timing of events such as those rituals dictated by ecclesiastical calendars requires precision to the month and day of an archaeological deposit and may not be possible based on seasonality studies alone. Evidence of a feast in an archaeological deposit might correspond to a ritual event celebrating Christian commemoration of the holy days of Christmas or Easter. The signature in a deposit for a feast has to be carefully evaluated though it might be expected to include a large source of meat such as pig (Sus scrofa) or white-tailed deer (Odocoileus virginianus) and accompanied by sweet fruits and nuts.

Many challenges exist in documenting the seasonal foraging patterns of the past and, therefore, it is particularly important to have the opportunity provided by this conference to exchange ideas and describe new and innovative approaches to the complex issues of seasonality. Eleven papers, all involved with efforts to understand seasons of capture or collection of different resources based on material excavated from archaeological deposits, were presented at the 2010 conference. Most importantly, the past conferences have resulted in four publications in the American Museum of Natural History Anthropological Papers series. The papers presented at this conference are now published in this fifth volume of the series. These are landmarks in the progress of research on the archaeology of St. Catherines Island.

Five of the papers are concerned with sclerochronology of the growth increments in the shells of bivalves or otoliths of fishes. Irvy Quitmyer and Douglas Jones applied these studies to the hard clam (Mercenaria mercenaria) and validated the season of the increments by oxygen isotope analysis. Nicole Cannarozzi studied growth increments with stable oxygen isotope analysis along the hinges of oysters (Crassostrea virginica) and supporting evidence from the growth measurements of the impressed odostome (Boonea impressa). Carol Colaninno applied the techniques of sclerochronology to otoliths of hardhead catfish (Ariopsis felis) and Atlantic croaker (Micropogonias undulatus). Douglas Kennett and Brendan Culleton applied a Bayesian statistical framework for determining site seasonality and contemporaneity. They advocate combining stratigraphic information with multiple AMS 14C dates. They apply this approach to the examination of the occupations of the two Archaic shell rings, St. Catherines and McQueen, and their contemporaneity.

Once clear criteria for seasonal changes are established, most participants advocated the use of multiple lines of evidence to better understand seasonal changes in foraging resources during pre-Hispanic and Mission periods. Multiple lines of evidence can strengthen conclusions or show variation in seasonal indicators. Elizabeth Reitz and Margaret Scarry examined the seasonal availability of a whole array of resources. Knowing when in a normal year buck deer shed their antlers, or fawns are born, or persimmons (Diospyros virginiana) ripen, provides clues about the season of capture or collection when the remains are recovered from archaeological deposits. Sarah Bergh also presented information on multiple seasonal indicators including data from hard clam sclerochronology, deer fusion sequences, and fish age and size classes, which the author suggests indicates year-round foraging of these animals. In addition to advocating use of multiple lines of evidence, Fred Andrus and Gregory Waselkov have legitimate concerns about adequacy of the sample sizes and the cost of some analyses.

The conference clearly achieved its purposes in stimulating lively debate and discussion about the accuracy of the methods used to estimate seasonal acquisition and uses of resources. It is, therefore, necessary to take the next step, as many of the authors have, and apply these techniques to gain a better understanding of the seasonal round of the people who lived on the island. The occupation at some sites was apparently of short duration. However, animal remains from these sites show use of resources throughout the year, indicating long-term occupations during each cultural period (Thomas, 2008: 878). Though clam sclerochronology data indicate that clams were gathered predominantly during the winter (mid-December to mid-March), a few clams were also gathered during other parts of the year (Thomas, chap. 1, this volume: fig. 1.3). When sources of seasonal information such as age of deer and the composition of the fish fauna in addition to the clam data are examined and combined for all cultural time periods, these catches appear to gradually decline through the year (seasonal indicators of winter catch are 32%, spring 28%, summer 24%, and fall 17% [Thomas, 2008: 878]). These samples are small, especially for the St. Simons period, and need further substantiation. However, if this is an accurate trend, one might expect a relatively greater dependence on plant resources collected during the summer and fall. Edible plants reported from the Mission era deposits are: chenopod (Chenopodium sp.), grape (Vitis sp.), blackberry (Rubus sp.), and elderberry (Sambucus sp.), available in the summer, and maize (Zea mays), acorns (Quercus sp.), and hickory (Carya sp.) nuts available in late summer and fall (Ruhl, 1993: table 15-11).

The difficulty in integrating data from plants with those from vertebrates and invertebrates lies in the relatively poorer preservation of plant remains. The only hopes for recovery of plant remains are when they were deposited in water-logged conditions of wet sites such as a well or when they have been burned, which renders them into bits of fragile charcoal. The anatomical features of the plant may still be preserved in the charcoal. Integrating these data with those from the generally robust remains of shell and bone is difficult. Nevertheless, some assessment of the relative contribution of all remains to the past diet provides a more complete view of conditions in the past.

Other plants that must have been used but whose remains are invisible are fiber plants essential for making nets, baskets, and weirs. These must have been used to catch the small fishes and those species that are reluctant to bite a hook such as mullet (Mugil sp.) found in the faunal remains. Some pottery has net impressions on it, further substantiating the presence of netting in the past (Royce Hayes, personal commun.). There is a long tradition by the Gullah people living on the Georgia Sea Islands for making baskets out of sweet grass (Muhlenbergia filipes) stitched together with palm leaves (Sabal palmetto). These plants are available, as is bear grass (Nolina sp. or Yucca sp.), which may have been used for netting (Royce and Christa Hayes, personal commun.). Weirs and baskets might also have been made using cane (Arundanaria gigantea), which apparently became quite abundant in response to clearing during the Mission period (Donna Ruhl, personal commun.). Using fiber plants to make baskets and nets would have been essential to catch small fishes, and to carry and store plant and animal products.

In addressing issues of mobility, many important resources known to have been used throughout the year would have been within easy reach from the forest and shore margin. Or they would have been within the economic foraging distance of 10 km (Thomas, 2008: 245). Furthermore, transport would have been much easier with nets and baskets. Along the marine edge, access to fishes, shellfish, diamondback terrapin (Malaclemys terrapin), raccoon (Procyon lotor), and white-tailed deer is documented (Reitz et al., 2010). During the fall, the mast crop would have attracted both people and mammals such as deer and raccoon, creating an opportunity akin to garden hunting which might have made hunting more successful. The maize crop would also be subject to plunder from many animals and guarding the produce would be garden hunting in the original sense of the term (Reitz et al., 2010). During the Spanish period, sea catfishes (Ariidae) were very abundant in the faunal samples. As scavengers, they were probably attracted to the Spanish mission period disposal of trash in the estuary, another form of garden hunting (Reitz et al., 2010: 162).

Access to fishery resources greatly expands the carrying capacity of the dry land because tides and currents bring nutrients to fishing grounds from coastal waters (Odum, 1971). Likewise, domestic animals such as pigs concentrate nutrients making them available to people who consume the meat. Few remains of domestic mammals were recovered from the Mission period deposits, however (Reitz et al., 2010). Most surprising is the scarcity of dog (Canis familiaris) remains in the deposits. Dogs would be expected in both pre-Hispanic and Hispanic deposits and might have been useful hunting companions and assistants.

All of the remains discussed so far are based on excavated archaeological deposits. Every archaeologist wishes at some point to have a firsthand look at the activities of people who lived in the past. Documents written by Jesuits during the Mission period on the island described the situation as the most miserable thing ever discovered. The impression was that the people wandered about and that the soil was too poor to support a crop. The Jesuit mission attempt coincided with an extreme and extended drought, which resulted in a deteriorating resource base. The disruption of the normal subsistence strategies and the demands of the mission resulted in deteriorating health, disease, social and physiological stress, and demographic collapse (Reitz et al., 2010: 133). The short-lived Jesuit mission was followed by a more sustained Franciscan mission. The Franciscan view of the Guale people was quite different. They were portrayed as living in ranked society in sedentary towns and cultivating maize (Thomas, chap. 1, this volume). These two very different eyewitness accounts may both be accurate and reflect the conditions the writers saw during the very difficult climatic disruption while the Jesuits were on the island and the return to more normal, less threatening time during the Franciscan mission (Thomas, 2008).

The expansion of archaeological techniques such as those examining seasonal change in animals discussed at this conference and the further integration of data from such diverse sources as plant charcoal, tree rings, growth increments of mollusc shells and fish otoliths, and remains of fish faunal assemblages are providing ever more complete understanding of human conditions in the past. Eyewitness accounts are, of course, most valuable to have but must be “ground truthed” by archaeology for biases and partial understanding.

REFERENCES

Abbott, L.E., Jr., E.E. Sanborn, L.E. Raymer, L.D. O’Steen, W. Cleary, and G.C. Turner. 1999. Data recovery at 31CB114, Columbus County, North Carolina: prehistoric settlement and subsistence practices within the Lower Cape Fear River valley. Manuscript on file at the Office of State Archaeology, Raleigh, NC.

Addessi, E., A. Mancini, L. Crescimbene, D. Ariely, and E. Visalberghi. 2010. How to spend a token? trade-offs between food variety and food preference in tufted capuchin monkeys (Cebus apella). Behavioural Processes 83 (3): 267. http://dx.doi.org/10.1016/j.beproc.2009.12.012

Ames, K.M. 2002. Going by boat: the forager-collector continuum at sea. In B. Fitzhugh and J. Habu (editors), Beyond foraging and collecting: evolutionary change in hunter gatherer settlement systems: 19–52. New York: Kluwer Academic.

Anderson, D.G. 1994. The Savannah River chiefdoms: political change in the late prehistoric Southeast. Tuscaloosa: University of Alabama Press.

Anderson, D.G., D.W. Stahle, and M.K. Cleaveland. 1995. Paleoclimate and the potential food reserves of Mississippian societies: a case study from the Savannah River Valley. American Antiquity 60 (2): 258–286. http://dx.doi.org/10.2307/282140

Andreasson, F.P., B. Schmitz, and E. Jönsson. 1999. Surface-water seasonality from stable isotope profiles of Littorina littorea shells: implications for paleoenvironmental reconstructions of coastal areas. Palaios 14: 273–281. http://dx.doi.org/10.2307/3515439

Andrus, C.F.T., and D.E. Crowe. 2000. Geochemical analysis of Crassostrea virginica as a method to determine season of capture. Journal of Archaeological Science 27: 33–42. http://dx.doi.org/10.1006/jasc.1999.0417

Andrus, C.F.T., and D.E. Crowe. 2002. Alteration of otolith aragonite: effects of prehistoric cooking methods on otolith chemistry. Journal of Archaeological Science 29: 291–299. http://dx.doi.org/10.1006/jasc.2001.0694

Andrus, C.F.T., and D.E. Crowe. 2008. Isotope analysis as a means for determining season of capture for Mercenaria. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 498–518.

Andrus, C.F.T., and K.W. Rich. 2008. A preliminary assessment of oxygen isotope fractionation and growth increment periodicity in the estuarine clam Rangia cuneata. Geo-Marine Letters 28: 301–308. http://dx.doi.org/10.1007/s00367-008-0109-3

Andrus, C.F.T., D.E. Crowe, D.H. Sandweiss, E.J. Reitz, and C.S. Romanek. 2002. Otolith δ18O record of Mid-Holocene sea surface temperatures in Peru. Science 295: 1508–1511. http://dx.doi.org/10.1126/science.1062004

Ansell, A.D. 1968. The rate of growth of the hard clam Mercenaria mercenaria (L.) throughout the geographical range. Journal du Conseil – Conseil International pour l’Exploration de la Mer 31: 364–409.

Arnold, W.S., D.C. Marelli, T.M. Bert, D.S. Jones, and I.R. Quitmyer. 1991. Habitat specific growth of hard clams Mercenaria mercenaria (L.) from the Indian River, Florida. Journal of Experimental Marine Biology and Ecology 147: 245–265. http://dx.doi.org/10.1016/0022-0981(91)90185-Y

Aten, L.E. 1981. Determining seasonality of Rangia cuneata from Gulf Coast shell middens. Bulletin of the Texas Archaeological Society 52: 179–200.

Bailey, G.N., and A.S. Craighead. 2003. Late Pleistocene and Holocene coastal palaeoeconomies: a reconsideration of the molluscan evidence from northern Spain. Geoarchaeology 18 (2): 175–204. http://dx.doi.org/10.1002/gea.10057

Bailey, G.N., M.R. Deith, and N.J. Shackleton. 1983. Oxygen isotope analysis and seasonality determinations: limits and potential of a new technique. American Antiquity 48: 390–398. http://dx.doi.org/10.2307/280460

Balasse, M., A.B. Smith, S.H. Ambrose, and S.R. Leigh. 2003. Determining sheep birth seasonality by analysis of tooth enamel oxygen isotope ratios: the Late Stone Age site of Kasteelberg (South Africa). Journal of Archaeological Science 30: 205–215. http://dx.doi.org/10.1006/jasc.2002.0833

Barats, A., D. Amouroux, L. Chauvaud, C. Pécheyran, A. Lorrain, J. Thébault, T.M. Church, and O.F.X. Donard. 2009. High frequency barium profiles in shells of the great scallop Pecten maximus: a methodological long-term and multi-site survey in Western Europe. Biogeosciences 6: 157–170. http://dx.doi.org/10.5194/bg-6-157-2009

Bartram, W. 1928. Travels of William Bartram. New York: Macy-Macius. [Reprinted in 1955 by Dover Publications, New York.]

Bar-Yosef, O., and. T.R. Rocek. 1998. Introduction. In T.R. Rocek and O. Bar-Yosef (editors), Seasonality and sedentism: archaeological perspectives from Old and New World sites: 1–8. Peabody Museum of Archaeology and Ethnology Bulletin No. 6, Cambridge, MA: Harvard University.

Bayliss, A., and C. Bronk Ramsey. 2004. Pragmatic Bayesians: a decade of integrating radiocarbon dates into chronological models. In C.E. Buck and A.R. Millard (editors), Tools for constructing chronologies: crossing disciplinary boundaries: 25–41. Lecture notes in statistics 177. New York: Springer.

Bayliss, A., C. Groves, G. McCormac, M. Baillie, D. Brown, and M. Brennand. 1999. Precise dating of the Norfolk timber circle. Nature 402: 479. http://dx.doi.org/10.1038/44993

Bayliss, A., C. Bronk Ramsey, J. van der Plicht, and A. Whittle. 2007. Bradshaw and Bayes: toward a timetable for the Neolithic. Cambridge Archaeological Journal 17: 1–28. http://dx.doi.org/10.1017/S0959774307000145

Bennett, C.E. (translator). 1975. Three voyages—René Laudonière. Gainesville: University of Florida Press.

Bettinger, R.L. 1991. Hunter-gatherers: archaeological and evolutionary theory. New York: Plenum Press.

Bettinger, R.L., R. Malhi, and H. McCarthy. 1997. Central place models of acorn and mussel processing. Journal of Archaeological Science 24: 887–899. http://dx.doi.org/10.1006/jasc.1996.0168

Beverly, R.K., W. Beaumont, D. Tauz, K.M. Ormsby, K.F. von Reden, G.M. Santos, and J.R. Southon. 2010. The Keck Carbon Cycle. AMS Laboratory, University of California, Irvine: Status Report. Radiocarbon 52.

Bigalke, E.H. 1973. The exploitation of shellfish by coastal tribesmen of the Transkei. Annual of the Cape Province Museum (Natural History) 9: 159–175.

Binford, L.R. 1980. Willow smoke and dogs’ tails: hunter-gatherer settlement systems and archaeological site formation. American Antiquity 45: 4–20. http://dx.doi.org/10.2307/279653

Binford, L.R. 1990. Mobility, housing, and environment: a comparative study. Journal of Anthropological Research 46 (2): 119–152.

Bird, D.W., and R. Bliege Bird. 2000. The ethnoarchaeology of juvenile foragers: shellfishing strategies among Meriam children. Journal of Anthropological Archaeology 19: 461–476. http://dx.doi.org/10.1006/jaar.2000.0367

Bird, D.W., R. Bliege Bird, and J.L. Richardson. 2004. Meriam ethnoarchaeology: shellfishing and shellmiddens. Memoirs of the Queensland Museum, Cultural Heritage Series 3 (1): 183–197.

Bishop, G.A., R.H. Hayes, B.K. Meyer, H.B. Rollins, F.J. Rich, D.H. Thomas, and R.K. Vance. 2007. Transgressive barrier island features of St. Catherines Island, Georgia. In F.J. Rich (editor), Fieldtrips of the 2007 annual meeting, Southeastern Section, Geological Society of America: 39–86. Statesboro, Georgia Southern University.

Bishop, G.A., B.K. Meyer, R.K. Vance, and F.J. Rich. 2011. Geoarchaeological research at St. Catherines Island: defining the geological foundation. In G.A. Bishop, H.B. Rollins, and D.H. Thomas (editors), Geoarchaeology of St. Catherines Island, Georgia. Anthropological Papers of the American Museum of Natural History 94: 79–98.

Bishop, G.A., H.B. Rollins, and D.H. Thomas (editors). 2011. Geoarchaeology of St. Catherines Island, Georgia. Anthropological Papers of the American Museum of Natural History 94.

Blackwell, P.G., C.E. Buck, and P.J. Reimer. 2006. Important features of the new radiocarbon calibration curves. Quaternary Science Reviews 25: 408–413. http://dx.doi.org/10.1016/j.quascirev.2005.12.001

Blanton, D.B. 2000. Drought as a factor in the Jamestown colony. Historical Archaeology 34 (4): 1606–1612.

Blanton, D.B. 2004. The climatic factor in late prehistoric and post-contact human affairs. In D.B. Blanton and J.A. King (editors), Indian and European contact: the mid-Atlantic region: 6–21. Gainesville: University Press of Florida.

Blanton, D.B., and D.H. Thomas. 2008. Paleoclimates and human responses along the central Georgia coast: a tree-ring perspective. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 799–806.

Bocherens, H., D. Billiou, A. Mariotti, M. Patou-Mathis, M. Otte, D. Bonjean, and M. Toussaint. 1999. Palaeoenvironmental and palaeodietary implications of isotopic biogeochemistry of last interglacial Neanderthal and mammal bones in Scladina Cave (Belgium). Journal of Archaeological Science 26 (6): 599–607. http://dx.doi.org/10.1006/jasc.1998.0377

Borrero, F.J., and T.J. Hilbish. 1988. Temporal variation in shell and soft tissue growth of the mussel Geukensia demissa. Marine Ecology Progress Series 42: 9–15. http://dx.doi.org/10.3354/meps042009

Breder, C.M. 1929. Field book of marine fishes of the Atlantic coast from Labrador to Texas; being a short description of their characteristics and habits with keys for their identification. New York: G.P. Putnam & Sons.

Bronk Ramsey, C. 1995. Radiocarbon calibration and analysis of stratigraphy: the OxCal program. Radiocarbon 37 (2): 461–474.

Bronk Ramsey, C. 2000. Comment on ‘The use of Bayesian statistics for 14C dates of chronologically ordered samples: a critical analysis.’ Radiocarbon 42: 199–202.

Bronk Ramsey, C. 2001. Development of the radiocarbon program OxCal. Radiocarbon 43 (2A): 355–363.

Bronk Ramsey, C. 2005. OxCal version 3.10. Internet resource (http://c14.arch.ox.ac.uk/embed.php?File=oxcal.html), accessed on December 8, 2011.

Bronk Ramsey, C., J. van der Plicht, and B. Weninger. 2001. ‘Wiggle Matching’ radiocarbon dates. Radiocarbon 43: 381–389.

Broughton, J.M. 2010. Prey spatial structure and behavior affect archaeological tests of optimal foraging models: examples from the Emeryville Shellmound vertebrate fauna. In J.M. Broughton and M.D. Cannon (editors), Evolutionary ecology and archaeology: applications to problems of human evolution and prehistory: 192–207. Salt Lake City: University of Utah Press.

Brown, I.W. 2003. Bottle Creek: a Pensacola culture site in south Alabama. Tuscaloosa: University of Alabama Press.

Brown, J.E. 1985. Long-term trends to sedentism and the emergence of complexity in the American Midwest. In T.D. Price and J.A. Brown (editors), Prehistoric hunter-gatherers: the emergence of cultural complexity: 201–231. San Diego, CA: Academic Press.

Brown, T.A., D.E. Nelson, J.S. Vogel, and J.R. Southon. 1988. Improved collagen extraction by modified Longin method. Radiocarbon 30 (2): 171–177.

Buck, C.E. 2004. Bayesian chronological data interpretation: where now? In C.E. Buck and A.R. Millard (editors), Tools for constructing chronologies: crossing disciplinary boundaries: 1–24. Lecture notes in statistics 177. London: Springer-Verlag.

Buck, C.E., and A.R. Millard (editors). 2004a. Tools for constructing chronologies: crossing disciplinary boundaries. London: Springer-Verlag.

Buck, C.E., and A.R. Millard. 2004b. Introduction. In C.E. Buck and A.R. Millard (editors), Tools for constructing chronologies: crossing disciplinary boundaries: I–VI. Lecture notes in statistics 177. London: Springer-Verlag.

Buck, C.E., C.D. Litton, and A.F.M. Smith. 1992. Calibration of radiocarbon results pertaining to related archaeological events. Journal of Archaeological Science 19 (5): 497–512. http://dx.doi.org/10.1016/0305-4403(92)90025-X

Buck, C.E., W.G. Cavanagh, and C.D. Litton. 1996. Bayesian approach to interpreting archaeological data. Chichester, UK: Wiley.

Buddemeier, R.W., J.E. Maragos, and D.W. Knutson. 1974. Radiographic studies of reef coral exoskeletons: rates and patterns of coral growth. Journal of Experimental Marine Biology and Ecology 14: 179–199. http://dx.doi.org/10.1016/0022-0981(74)90024-0

Builth, H. 2006. Gunditjmara environmental management: the development of a fisher-gatherer-hunter society in temperate Australia. In C. Grier, J. Kim, and J. Uchiyama (editors), Beyond affluent foragers: rethinking hunter-gatherer complexity: 4–23. Oxford: Oxbow Books.

Burman, J., and T. Påsse. 2008. Oceanography in northwestern Europe during the last interglacial from intrashell δ18O ranges in Littorina littorea gastropods. Quaternary Research 70: 121–128. http://dx.doi.org/10.1016/j.yqres.2008.03.007

Burman, J., and B. Schmitz. 2005. Periwinkle (Littorina littorea) intrashell δ18O and δ13C records from the mid-Holocene Limfjord region, Denmark: a new high-resolution palaeoenvironmental proxy approach. Holocene 15: 567–575. http://dx.doi.org/10.1191/0959683605hl831rp

Bushnell, A.T. 1990. The sacramental imperative: Catholic ritual and Indian sedentism in the provinces of Florida. In D.H. Thomas, Columbian consequences, archaeological and historical perspectives on the Spanish borderlands east: 475–490. Washington, DC: Smithsonian Institution Press.

Butler, V.L., and S.K. Campbell. 2004. Resource intensification and resource depression in the Pacific Northwest of North America: a zooarchaeological review. Journal of World Prehistory 18: 327–405. http://dx.doi.org/10.1007/s10963-004-5622-3

Butler, V.L., and M.G. Delacorte. 2004. Doing zooarchaeology as if it mattered: use of faunal data to address current issues in fish conservation biology in Owens Valley, California. In R.L. Lyman and K.P. Cannon (editors), Zooarchaeology and conservation biology: 25–44. Salt Lake City: University of Utah Press.

Caldwell, J.R. 1971. Chronology of the Georgia coast. Southeastern Archaeological Conference Bulletin 13: 89–91.

Campbell, S.K., and V.L. Butler. 2010. Archaeological evidence for resilience of Pacific Northwest salmon populations and the socioecological system over the last ~7,500 years. Ecology and Society 15 (1): 17.

Cannarozzi, N., and I. Quitmyer. 2007. Oyster schlerochronology helps archaeologists date sites. No Wake Zone 2 (1): 1.

Carlson D.L. 1987. Rangia cuneata as a seasonal indicator for coastal archaeological sites in Texas. Bulletin of the Texas Archaeological Society 58: 201–214.

Carré, M., I. Bentaleb, D. Blamart, N. Ogle, F. Cardenas, S. Zevallos, R.M. Kalin, L. Ortlieb, and M. Fontugne. 2005. Stable isotopes and sclerochronology of the bivalve Mesodesma donacium: potential application to Peruvian paleoceanographic reconstructions. Palaeogeography, Palaeoclimatology, Palaeoecology 228: 4–25. http://dx.doi.org/10.1016/j.palaeo.2005.03.045

Carré, M., L. Klaric, D. Lavallée, M. Julien, I. Bentaleb, M. Fontugne, and O. Kawka. 2009. Insights into early Holocene hunter-gatherer mobility on the Peruvian southern coast from mollusk gathering seasonality. Journal of Archaeological Science 36: 1173–1178. http://dx.doi.org/10.1016/j.jas.2009.01.005

Carriker, M.R. 1996. The shell and ligament. In V.S. Kennedy, R.I.E. Newell, and A.R. Eble (editors), The eastern oyster Crassostrea virginica: 75–168. College Park: Maryland Sea Grant College.

Carroll, M., C.S. Romanek, and L. Paddock. 2006. The relationship between the hydrogen and oxygen isotopes of freshwater bivalve shells and their home streams. Chemical Geology 234: 211–222. http://dx.doi.org/10.1016/j.chemgeo.2006.04.012

Cerrato, R.M. 1980. Demographic analysis of bivalve populations. In D.C. Rhodes and R.A. Lutz (editors), Skeletal growth of aquatic organisms: biological records of environmental change: 417–463. New York: Plenum Press.

Chittaro, P.M., P. Usseglio, B.J. Fryer, and P.F. Sale. 2005. Using otolith microchemistry of Haemulon flavolineatum (French Grunt) to characterize mangroves and coral reefs throughout Turneffe Atoll, Belize: difficulties at small spatial scales. Estuaries 28 (3): 373–381. http://dx.doi.org/10.1007/BF02693920

Chittaro, P.M., P. Usseglio, B.J. Fryer, and P.F. Sale. 2006. Spatial variation in otolith chemistry of Lutjanus apodus at Turneffe Atoll, Belize. Estuarine, Coastal and Shelf Science 67: 673–680. http://dx.doi.org/10.1016/j.ecss.2005.12.014

Claassen, C.P. 1982. Shellfishing patterns: an analytical study of prehistoric shell from North Carolina coastal middens. Ph.D. dissertation, Department of Anthropology, Harvard University, Cambridge.

Claassen, C. 1986. Shellfishing seasons in the prehistoric southeastern United States. American Antiquity 51 (1): 21–37. http://dx.doi.org/10.2307/280391

Claassen, C.P. 1990. Investigation of monthly growth in shellfish for application to archaeology. Final Report, National Science Foundation Grant # BNS-8507714.

Claassen, C. 1993. Problems and choices in shell seasonality studies and their impact on results. Archaeozoologica 5(2): 55–75.

Claassen, C. 1998. Shells. Cambridge, UK: Cambridge University Press.

Claassen, C., and S. Sigmann. 1993. Sourcing Busycon artifacts of the eastern United States. American Antiquity 58: 333–347. http://dx.doi.org/10.2307/281974

Clark, G.R., II. 1968. Mollusk shell: daily growth lines. Science 161: 800–802. http://dx.doi.org/10.1126/science.161.3843.800

Clark, G.R., II. 1974. Growth lines in invertebrate skeletons. Annual Review of Earth and Planetary Sciences 2: 77–99. http://dx.doi.org/10.1146/annurev.ea.02.050174.000453

Clark, G.R., II. 1976a. Seasonal growth variations in bivalve shells as indicators of human occupation patterns on St. Catherines Island, Georgia. Interim report New York, American Museum of Natural History.

Clark, G.R., II. 1976b. Interpretation of season of death of mollusk shells associated with burial mounds on St. Catherines Island, Georgia. Proposal. American Museum of Natural History.

Clark G.R., II. 1979. Seasonal growth variations in the shells of recent and prehistoric specimens of Mercenaria mercenaria from St. Catherines Island, Georgia. In D.H. Thomas and C.S. Larsen (editors), The anthropology of St. Catherines Island: 2. The Refuge-Deptford mortuary complex. Anthropological Papers of the American Museum of Natural History 56 (1): 161–179.

Cobb, R.M., C.F.T. Andrus, and M.F. Etayo-Cadavid. 2009. Rangia cuneata shells as an environmental proxy: variations in elemental concentrations within populations. University of Alabama McNair Journal 9: 45–58.

Cohen, M.N. 1977. The food crisis in prehistory: overpopulation and the origins of agriculture. New Haven, CT: Yale University Press.

Colaninno, C.E. 2010. Zooarchaeological analysis of vertebrate remains from five late Archaic shell rings of the Georgia coast, USA. Ph.D. dissertation, University of Georgia, Athens.

Collins, M.R. 1985. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (South Florida): striped mullet. U.S. Fish and Wildlife Service, Biological Report 82 (11.34).

Colonese, A.C., S. Troelstra, P. Ziveri, F. Martini, D. Lo Vetro and S. Tommasini. 2009. Mesolithic shellfish exploitation in SW Italy: seasonal evidence from the oxygen isotopic composition of Osilinus turbinatus shells. Journal of Archaeological Science 36: 1935–1944. http://dx.doi.org/10.1016/j.jas.2009.04.021

Comyns, B.H., C.F. Rakocinski, M.S. Peterson, and A.M. Shiller. 2008. Otolith chemistry of juvenile spotted seatrout Cynoscion nebulosus reflects local natal regions of coastal Mississippi, USA. Marine Ecology Progress Series 371: 243–252. http://dx.doi.org/10.3354/meps07604

Conover, D.O., and M.R. Ross. 1982. Patterns in seasonal abundance, growth and biomass of the Atlantic silverside, Menidia menidia, in a New England estuary. Estuaries 5 (4): 275–286. http://dx.doi.org/10.2307/1351750

Costanza, R., R. d’Arge, R. de Groot, S. Farber, M. Grasso, B. Hannon, K. Limburg, S. Naeem, R.V. O’Neill, J. Paruelo, R.G. Raskin, P. Sutton, and M. van den Belt. 1997. The value of the world’s ecosystem services and natural capital. Nature 387: 253–260. http://dx.doi.org/10.1038/387253a0

Coutts, P.J.F. 1970. Bivalve-growth patterning as a method for seasonal dating in archaeology. Nature 226: 874. http://dx.doi.org/10.1038/226874a0

Coutts, P.J.F. 1975. The seasonal perspective of marine-oriented prehistoric hunter–gatherers. In G.D. Rosenberg and S.K. Runcorn (editors), Growth rhythms and the history of the earth’s rotation: 243–252. London: Wiley.

Coutts, P.J.F., and T. Higham. 1971. The seasonal factor in prehistoric New Zealand. World Archaeology 2 (3): 266–277. http://dx.doi.org/10.1080/00438243.1971.9979480

Cox, K.A. 1994. Oysters as ecofacts. Bulletin of the Texas Archaeological Society 62: 219–247.

Craig, H. 1965. Measurement of oxygen isotope paleotemperatures. In E. Tongiori (editor), Stable isotopes in oceanographic studies: 161–182. Consiglio Nazionale delle Ricerche, Spoleto, Italy.

Crawford, K., R.A. McDonald, and S. Bearhop. 2008. Applications of stable isotope techniques to the ecology of mammals. Mammal Review 38 (1): 87–107. http://dx.doi.org/10.1111/j.1365-2907.2008.00120.x

Crites, G.D. 1999. Long Point (31JN2) plant remains. In M.S. Shumate and P. Evans-Shumate, Archaeological investigations at Long Point (31JN2) and Haywood Landing (31JN3) on the Croatan National Forest, Jones County, North Carolina. Ms. on file at the Office of State Archaeology, Raleigh, NC.

Crook, M.R., Jr. 1978. Mississippian period community organizations on the Georgia coast. Ph.D. dissertation, University of Florida, Gainesville.

Crook, M.R., Jr. 1984. Evolving community organization on the Georgia coast. Journal of Field Archaeology 11 (3): 247–263. http://dx.doi.org/10.1179/009346984791535485

Crook, M.R., Jr. 1986. Mississippi period archaeology of the Georgia coastal zone. University of Georgia Laboratory of Archaeology, series report 23.

Crook, M.R., Jr. 1992. Oyster sources and their prehistoric use on the Georgia coast. Journal of Archaeological Science 19: 483–496. http://dx.doi.org/10.1016/0305-4403(92)90024-W

Crook, M.R., Jr. 2004. Late prehistoric settlement mobility on the Georgia coast. Unpublished ms.

Culleton, B.J., D.J. Kennett, B.L. Ingram, J. Erlandson, and J. Southon. 2006. Intra-shell radiocarbon variability in marine mollusks. Radiocarbon 43 (3): 387–400.

Culleton, B.J., D.J. Kennett, and T.L. Jones. 2009. Oxygen isotope seasonality in a temperate estuarine shell midden: a case study from CA-ALA-17 on the San Francisco Bay, California. Journal of Archaeological Science 36 (7): 1354–1363. http://dx.doi.org/10.1016/j.jas.2009.01.021

Cusack, M., D. Parkinson, A. Freer, A. Pérez-Huerta, A.E. Fallick, and G.B. Curry. 2008. Oxygen isotope composition in Modiolus modiolus aragonite in the context of biological and crystallographic control. Mineralogical Magazine 72: 569–577. http://dx.doi.org/10.1180/minmag.2008.072.2.569

Custer, J.F., and K.R. Doms. 1990. Analysis of microgrowth patterns of American oyster (Crassostrea virginica) in the Middle Atlantic Region of Eastern North America: archaeological applications. Journal of Archaeological Science 17: 151–160. http://dx.doi.org/10.1016/0305-4403(90)90056-B

Dahlberg, M.D. 1972. An ecological study of Georgia coastal fishes. Fishery Bulletin 70 (2): 323–353.

Dahlberg, M.D. 1975. Guide to coastal fishes of Georgia and nearby states. Athens: University of Georgia Press.

Dahlberg, M.D., and E.P. Odum. 1970. Annual cycles of species occurrence, abundance, and diversity in Georgia estuarine fish populations. American Midland Naturalist 83: 382–392. http://dx.doi.org/10.2307/2423951

Dawson, T.E., and R.T.W. Siegwolf. 2007. Using stable isotopes as indicators, tracers, and recorders of ecological change. In T.E. Dawson and R.T.W. Siegwolf (editors), Stable isotopes as indicators of ecological change: 3–18. Amsterdam: Elsevier.

de Boer, W.F., T. Pereira, and A. Guissamulo. 2000. Comparing recent and abandoned shell middens to detect the impact of human exploitation on the intertidal ecosystem. Aquatic Ecology 34 (3): 287–297. http://dx.doi.org/10.1023/A:1009957409421

Deevey, E.S., Jr. 1947. Life tables of natural populations of animals. Quarterly Review of Biology 22: 283–314. http://dx.doi.org/10.1086/395888

DEIS. 1978. Draft environmental impact statement for preferred alternative location for a fleet ballistic missile (FBM) submarine support base. Appendix 2. Washington, DC: Department of the Navy.

Deith, M.R. 1983. Molluscan calendars: the use of growth-line analysis to establish seasonality of shellfish collection at the Mesolithic site of Morton, Fife. Journal of Archaeological Science 10: 423–440. http://dx.doi.org/10.1016/0305-4403(83)90058-4

Deith, M.R. 1986. Subsistence strategies at a Mesolithic camp site: evidence from stable isotope analyses of shells. Journal of Archaeological Science 13 (1): 61–78. http://dx.doi.org/10.1016/0305-4403(86)90027-0

DeNiro, M.J. 1985. Postmortem preservation and alteration of in vivo bone collagen isotope ratios in relation to paleodietary reconstruction. Nature 317: 806–809. http://dx.doi.org/10.1038/317806a0

DePratter, C.B. 1979. Ceramics. In D.H. Thomas and C.S. Larsen (editors), The anthropology of St. Catherines Island: 2. The Refuge-Deptford mortuary complex. Anthropological Papers of the American Museum of Natural History 56 (1): 109–132.

DePratter, C.B. 1991. W.P.A. archaeological excavations in Chatham County, Georgia: 1937–1942. University of Georgia, Laboratory of Archaeology Series, Report 29.

Dettman, D.L., A.K. Reische, and K.C. Lohmann. 1999. Controls on the stable isotope composition of seasonal growth bands in aragonitic fresh-water bivalves (Unionidae). Geochimica et Cosmochimica Acta 63: 1049–1057. http://dx.doi.org/10.1016/S0016-7037(99)00020-4

Detwiler, K., and D. Keene. 2003. Rethinking late prehistoric subsistence on the Georgia coast: evidence for agriculture at the Grove’s Creek Site (09CH71). Paper presented at the 26th Annual Conference of the Society of Ethnobiology, Seattle.

Detwiler, K. and C.M. Scarry. 1999. Plant remains. In R. Daniel, Archaeological excavations at Hammocks Beach West (31ON665): a Woodland shell midden on the North Carolina coast: 149–156. Occasional Papers of the Phelps Archaeology Laboratory No. 1. East Carolina University.

Devereux, I. 1967. Temperature measurements from oxygen isotope ratios of fish otoliths. Science 155: 1684–1685. http://dx.doi.org/10.1126/science.155.3770.1684

Dolan, R., B. Hayden, and H. Lins. 1980. Barrier islands. American Scientist 68: 16–25.

Dorval, E., C.M. Jones, R. Hannigan, and J. van Montfrans. 2004. Can otolith chemistry be used for identifying essential seagrass habitats for juvenile spotted seatrout, Cynoscion nebulosus, in Chesapeake Bay? Marine and Freshwater Research 56 (5): 645–653. http://dx.doi.org/10.1071/MF04179

Drake, J.C. 1891. On the sounds and estuaries of Georgia with reference to oyster culture. U.S. Coast and Geodetic Survey Bulletin 19: 179–209.

Drennan, R.D. 2010. Statistics for archaeologists, 2nd edition: a common sense approach (interdisciplinary contributions to archaeology). New York: Plenum Press.

Eble, A.F., and R. Scro. 1996. General anatomy. In V.S. Kennedy, R.I.E. Newell, and A.F. Eble (editors), The eastern oyster Crassostrea virginica: 19–73. Maryland Sea Grant College, College Park.

Elliot, M., P.B. deMenocal, B.K. Linsley, and S.S. Howe. 2003. Environmental controls on the stable isotopic composition of Mercenaria mercenaria: potential application to paleoenvironmental studies. Geochemistry Geophysics Geosystems 4: 1–16. http://dx.doi.org/10.1029/2002GC000425

Elston, R.G., and D. Zeanah. 2002. Thinking outside the box: a new perspective on diet breadth and sexual division of labor in the prearchaic Great Basin. World Archaeology 34: 103–130. http://dx.doi.org/10.1080/00438240220134287

Emiliani, C., L. Cardini, T. Mayeda, C.B.M. McBurney, and E. Tongiorgi. 1964. Palaeotemperature analysis of marine molluscs (food refuse) from the site of Arene Candide Cave, Italy and the Haua Fteah Cave, Cyrenaica. In H. Craig, S.L. Miller, and G. J. Wasserburg, (editors), Isotopic and cosmic chemistry: 133–156. Amsterdam: North Holland Pub. Co.

Epstein, S., and H.A. Lowenstam. 1953. Temperature–shell-growth relations of recent and interglacial Pleistocene shoal-water biota from Bermuda. Journal of Geology 61: 424–130. http://dx.doi.org/10.1086/626110

Epstein, S., R. Buchsbaum, H.A. Lowenstam, and H.C. Urey. 1953. Revised carbonate-water isotopic temperature scale. Bulletin of the Geological Society of America 64: 1315–1326. http://dx.doi.org/10.1130/0016-7606(1953)64[1315:RCITS]2.0.CO;2

Erickson, C.L. 2000. An artificial landscape-scale fishery in the Bolivian Amazon. Nature 408: 190–193. http://dx.doi.org/10.1038/35041555

Erlandson, J.M. 1994. Early hunter-gatherers of the California coast. New York: Plenum Press.

Erlandson, J.M. 2001. The archaeology of aquatic adaptations: paradigms for a new millennium. Journal of Archaeological Research 9 (4): 287–350. http://dx.doi.org/10.1023/A:1013062712695

Erlandson, J.M., T.C. Rick, T.J. Braje, A. Steinberg, and R.L. Vellanoweth. 2008. Human impacts on ancient shellfish: a 10,000 year record from San Miguel Island, California. Journal of Archaeological Science 35 (8): 2144–2152. http://dx.doi.org/10.1016/j.jas.2008.01.014

Etayo-Cadavid, M.F. 2010. Peruvian mollusk shells as multi-proxy archives: Late Holocene upwelling variation and El Niño–induced biomineralization effects on trace elements. Ph.D. dissertation, University of Alabama, Tuscaloosa.

Evershed, R.P., I.D. Bull, L.T. Corr, Z.M. Crossman, B.E. Van Dongen, C.J. Evans, S. Jim, H.R. Mottram, A.J. Mukherjee, and R.D. Pancost. 2007. Compound-specific stable isotope analysis in ecology and paleoecology. In R. Michener and K. Lajtha (editors), Stable isotopes in ecology and environmental science, 2nd ed.: 480–540. Malden, MA: Blackwell. http://dx.doi.org/10.1002/9780470691854.ch14

Eversole, A.G., W.D. Anderson, and J.J. Isely.
2008. Age and growth of the knobbed whelk Busycon carica (Gmelin 1791) in South Carolina subtidal waters. Journal of Shellfish Research 27: 423–426. http://dx.doi.org/10.2983/0730-8000(2008)27[423:AAGOTK]2.0.CO;2

Fagan, B.M. 2000. The Little Ice Age: how climate made history 1300–1850. New York: Basic Books.

Fagan, B.M. 2005. The long summer: how climate changed civilization. New York: Basic Books.

Fairbanks, L.D. 1963. Biodemographic studies of the clam Rangia cuneata Gray. Tulane Studies in Zoology 10: 3–47.

Fegley, S.R. 2001. Demography and dynamics of hard clam populations. In J.N. Kraeuter and M. Castagna, Biology of the hard clam: 381–422. Amsterdam: Elsevier.

Ferrio, J.P., J. Voltas, N. Alonso, and J.L. Araus. 2007. Reconstruction of climate and crop conditions in the past based on the carbon isotope signature of archaeobotanical remains. In T.E. Dawson and R.T.W. Siegwolf (editors), Stable isotopes as indicators of ecological change: 319–332. Amsterdam: Elsevier.

Fives, J.M., S.M. Warlen, and D.E. Hoss. 1986. Aging and growth of larval bay anchovy, Anchoa mitchilli, from the Newport River estuary, North Carolina. Estuaries 9 (4): 362–367. http://dx.doi.org/10.2307/1351416

Flannery, K.V. 1968. Archaeological systems theory and early Mesoamerica. In B.J. Meggers (editor), Anthropological archeology in the Americas: 67–87. Washington DC: Anthropological Society of Washington.

Fodrie, F.J., and S.Z. Herzka. 2008. Tracking juvenile fish movement and nursery contribution within arid coastal embayments via otolith microchemistry. Marine Ecology Progress Series 361: 253–265. http://dx.doi.org/10.3354/meps07390

Fodrie, F.J., K.L. Heck, J.P. Powers, W.M. Graham, and K.L. Robinson. 2010. Climate-related, decadal-scale assemblage changes of seagrass-associated fishes in the northern Gulf of Mexico. Global Change Biology 16 (1): 48–59. http://dx.doi.org/10.1111/j.1365-2486.2009.01889.x

Ford, H. L., S.A. Schellenberg, B.J. Becker, D.L. Deutschman, K.A. Dyck, and P.L. Koch. 2010. Evaluating the skeletal chemistry of Mytilus californianus as a temperature proxy: effects of microenvironment and ontogeny. Paleoceanography 25: PA1203. http://dx.doi.org/10.1029/2008PA001677

Fowler, A.J. 1995. Annulus formation in otoliths of coral reef fish—a review. In D.H. Secor, J.M. Dean, and S.E. Campana (editors), Recent developments in fish otolith research: 45–63. University of South Carolina Press, Columbia.

Fowler, C.S. 2008. Historical perspectives on Timbisha Shoshone land management practices, Death Valley, California. In E.J. Reitz, C.M. Scarry, S. Scudder (editors), Case studies in environmental archaeology, 2nd ed.: 43–57. New York: Springer. http://dx.doi.org/10.1007/978-0-387-71303-8_3

Fradkin, A. 2008. Applying a measure for determining season of oyster harvesting: a case study of a pre-Columbian Florida site, USA. Archaeofauna 17: 147–156.

France, R. 1995. Stable nitrogen isotopes in fish: literature synthesis on the influence of ecotonal coupling. Estuarine, Coastal and Shelf Science 41: 737–742. http://dx.doi.org/10.1006/ecss.1995.0087

Frey, R.W., and J.D. Howard. 1986. Mesotidal estuarine sequences: a perspective from the Georgia Bight. Journal of Sedimentary Petrology 56 (6): 911–924.

Fritz, G.J., V. Drywater Whitekiller, and J.W. McIntosh. 2001. Ethnobotany of Ku-nu-che: Cherokee hickory nut soup. Journal of Ethnobiology 21 (2):1–27.

Fritz, L.W. 2001. Shell structure and age determination. In J.N. Kraeuter and M. Castagna (editors), Biology of the hard clam: 53–76. London, New York: Elsevier.

Fry, B. 2002. Conservative mixing of stable isotopes across estuarine salinity gradients: a conceptual framework for monitoring watershed influences on downstream fisheries production. Estuaries 25 (2): 264–271. http://dx.doi.org/10.1007/BF02691313

Fuller, D.Q., R. Korisettar, and P.C. Venkatasubbaiah. 2001. Southern Neolithic cultivation systems: reconstruction based on archaeobotanical evidence. South Asian Studies 17: 171–187.

Galtsoff, P.S. 1964. The American oyster Crassostrea virginica Gmelin. U.S. Department of the Interior, Fish and Wildlife Service, Bureau of Commercial Fisheries, Fishery Bulletin 64.

Gardner, P.S. 1984. Floral analysis. Appendix E. In M. Wilde-Ramsing, Archaeological survey and testing on prehistoric shell midden sites in New Hanover County, North Carolina: 156–158. Unpublished M.A. thesis, Department of Anthropology, Catholic University of America.

Gardner, P.S. 1990. Excavations at the Amity Site: final report of the Pomeiooc Project: 1984–1989. Archaeological Research Report 7 (OSA # 2771). East Carolina University, Greenville.

Gardner, P.S. 1997. The ecological structure and behavioral implications of mast exploitation strategies. In K. Gremillion (editor), People, plants, and landscapes: 161–178. Tuscaloosa: University of Alabama Press.

Gillikin, D.P., F. Dehairs, A. Lorrain, D. Steenmans, W. Baeyens, and L. André. 2006. Barium uptake into the shells of the common mussel (Mytilus edulis) and the potential for estuarine paleo-chemistry reconstruction. Geochimica et Cosmochimica Acta 70: 395–407. http://dx.doi.org/10.1016/j.gca.2005.09.015

Gilmore, M.R. 1931. Dispersal by Indians, a factor in the extension of discontinuous distribution of certain species of native plants. Papers of the Michigan Academy of Science, Arts and Letters 13: 89–94

Glassow, M.A. 1997. Research issues of importance to coastal California archaeology of the middle Holocene. In J.M. Erlandson and M.A. Glassow (editors), Archaeology of the California coast during the middle Holocene: 151–161. Los Angeles: Institute of Archaeology, University of California.

Glazier, E. 1987. Ethnobotanical analysis: Late Woodland plant food utilization along the Central North Carolina Coast. Appendix 1. In T.C. Loftfield, Excavations at 31On305, the Flynt Site at Sneads Ferry, North Carolina (OSA # 2190). Manuscript on file, Office of State Archaeology, Raleigh, NC.

Goewert, A., D. Surge, S.J. Carpenter, and J. Downing. 2007. Oxygen and carbon isotope ratios of Lampsilis cardium (Unionidae) from two streams in agricultural watersheds of Iowa, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 252: 637–648. http://dx.doi.org/10.1016/j.palaeo.2007.06.002

Goffer, Z. 2007. Archaeological chemistry, 2nd ed. Hoboken, NJ: Wiley-Interscience. http://dx.doi.org/10.1002/0471915254

Goodwin, D. H., B.R. Schöne, and D.L. Dettman. 2003. Resolution and fidelity of oxygen isotopes as paleotemperature proxies in bivalve mollusk shells: models and observations. Palaios 18: 110–125. http://dx.doi.org/10.1669/0883-1351(2003)18<110:RAFOOI>2.0.CO;2

Gorski, L. 2005. Microstratigraphic analysis at the Carlston Annis site, Butler County, Kentucky. In W.H. Marquardt and P.J. Watson (editors), Archaeology of the Middle Green River Region, Kentucky: 153–166. Gainesville: Institute of Archaeology and Paleoenvironmental Studies Monograph 5, University of Florida.

Gosselain, O.P. 1998. Social and technical identity in a clay crystal ball. In M.T. Stark (editor), The archaeology of social boundaries: 78–106. Washington, DC: Smithsonian Institution Press.

Green, P.R. 1984. Appendix C. Ethnobotanical analysis of samples from the Wanchese Site, 31Dr35. In D.S. Phelps, The archaeology of the Tillett Site: the first fishing community at Wanchese, Roanoke Island: 103–107 (OSA # 1627). Archaeological Research Report 6. East Carolina University, Greenville, NC.

Green, P.R. 1986. The archaeology of “Chowanoke”: results of the 1983–1984 investigations at Mount Pleasant and Liberty Hill, Hertford County, North Carolina (OSA # 3279). Ms. on file, Office of State Archaeology, Raleigh, NC.

Gremillion, K.J. 2002. Foraging theory and hypothesis testing in archaeology: an exploration of methodological problems and solutions. Journal of Anthropological Archaeology 21: 142–164. http://dx.doi.org/10.1006/jaar.2001.0391

Grimes, S.T., D.P. Mattey, J.J. Hooker, and M.E. Collinson. 2003. Paleogene paleoclimate reconstruction using oxygen isotopes from land and freshwater organisms: the use of multiple paleoproxies. Geochimica et Cosmochimica Acta 67 (21): 4033–4047. http://dx.doi.org/10.1016/S0016-7037(03)00173-X

Grossman, E.L. and T.-L. Ku. 1986. Oxygen and carbon isotopic fractionation in biogenic aragonite: temperature effects. Chemical Geology 59: 59–74. http://dx.doi.org/10.1016/0168-9622(86)90057-6

Gunter, G. 1947. Observations on breeding of the marine catfish, Galeichthys felis (Linnaeus). Copeia 4: 217–223. http://dx.doi.org/10.2307/1438916

Habu, J. 2002. Jomon collectors and foragers. In B. Fitzhugh and J. Habu (editors), Beyond foraging and collecting: evolutionary change in hunter-gatherer settlement systems: 53–72. New York: Kluwer Academic.

Habu, J., and B. Fitzhugh. 2002. Introduction: beyond foraging and collecting: evolutionary change in hunter-gatherer settlement systems. In B. Fitzhugh and J. Habu (editors), Beyond foraging and collecting: evolutionary change in hunter-gatherer settlement systems: 1–14. New York: Kluwer Academic.

Haddon, M. 2001. Modeling and quantitative methods in fisheries. Boca Raton, FL: Chapman and Hall/CRC. 406 p.

Hallam, A. 1972. Models involving population dynamics. In T.J.M. Schoph (editor), Models in paleobiology: 62–81. San Francisco: Freeman, Cooper.

Hales, L.S., Jr., and E.J. Reitz. 1992. Historical changes in age and growth of Atlantic croaker, Micropogonias undulatus (Perciformes: Sciaenidae). Journal of Archaeological Science 19: 73–99. http://dx.doi.org/10.1016/0305-4403(92)90008-Q

Hales, L.S., and M.J. Van Den Avyle. 1989. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (South Atlantic): spot. U.S. Fish and Wildlife Service, Biological Report 82 (11.91).

Ham, L.C., and M. Irvine. 1975. Techniques for determining seasonality of shell middens from marine mollusc remains. Syesis 8: 363–373.

Hames, R. 2007. The ecologically noble savage debate. Annual Review of Anthropology 36: 177–190. http://dx.doi.org/10.1146/annurev.anthro.35.081705.123321

Hammen, C.S. 1969. Metabolism of the oyster, Crassostrea virginica. American Zoologist 9 (2): 309–318.

Hann, J.H. 1986a. Translation of Alonso de Leturiondo’s memorial to the king of Spain; AGI, SD 853, SC. Florida Archaeology 2: 165–225.

Hann, J.H. 1986b. Demographic patterns and changes in mid-seventeenth century Timucua and Apalachee. Florida Historical Quarterly 64 (4): 371–392.

Hanson, P.J., C.C. Koenig, and V.S. Zdanowicz. 2004. Elemental composition of otoliths used to trace estuarine habitats of juvenile gag Mycteroperca microlepsis along the west coast of Florida. Marine Ecology Progress Series 267: 253–265. http://dx.doi.org/10.3354/meps267253

Harding, J.M., H.J. Spero, R. Mann, G.S. Herbert, and J.L. Sliko. 2010. Reconstructing early 17th century estuarine drought conditions from Jamestown oysters. Proceedings of the National Academy of Sciences 107: 10549–10554. http://dx.doi.org/10.1073/pnas.1001052107

Hare, J.A., and K.W. Able. 2007. Mechanistic links between climate and fisheries along the east coast of the United States: explaining population outbursts of Atlantic croaker (Micropogonias undulatus). Fisheries Oceanography 16 (1): 31–45. http://dx.doi.org/10.1111/j.1365-2419.2006.00407.x

Hawkes, K. 1996. Foraging differences between men and women: behavioural ecology of the sexual division of labour. In J. Steele and S. Shennan (editors), The archaeology of human ancestry: 283–305. New York: Routledge.

Hayden, B. 1990. Nimrods, piscators, pluckers, and planters: the emergence of food production. Journal of Anthropological Archaeology 9: 31–69. http://dx.doi.org/10.1016/0278-4165(90)90005-X

Hayden, B. 1995. A new overview of domestication. In T.D. Price and A.B. Gebauer (editors), Last hunters—first farmers: new perspectives on the prehistoric transition to agriculture: 273–299. Santa Fe: School of American Research Press.

Hayden, B.P., and R. Dolan. 1979. Barrier islands, lagoons, and marshes. Journal of Sedimentary Petrology 49: 1061–1072.

Hayes, M.O. 1994. The Georgia Bight barrier system. In R.A. Davis, Jr. (editor), Geology of Holocene barrier island systems: 233–304. Berlin: Springer-Verlag.

Hayes, R.H., and D.H. Thomas. 2008. Hydrology of St. Catherines Island. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. I. The theoretical framework. Anthropological Papers of the American Museum of Natural History 88: 56–58.

Hedges, R.E.M., R.E. Stevens, and M.P. Richards. 2004. Bone as a stable isotope archive for local climatic information. Quaternary Science Reviews 23: 959–965. http://dx.doi.org/10.1016/j.quascirev.2003.06.022

Hedges, R.E.M., R.E. Stevens, and P.L. Koch. 2005. Isotopes in bones and teeth. In M.J. Leng (editor), Isotopes in palaeoenvironmental research: 117–145. Dordrecht: Springer.

Henry, K.M., and R.M. Cerrato. 2007. The annual macroscopic growth pattern of the northern quahog (hard clam, Mercenaria mercenaria [L.]), in Narragansett Bay, Rhode Island. Journal of Shellfish Research 26 (4): 985–993. http://dx.doi.org/10.2983/0730-8000(2007)26[985:TAMGPO]2.0.CO;2

Herbert, J.M., and L.C. Steponaitis. 1998. Estimating the season of harvest of eastern oysters (Crassostrea virginica) with shells from the Chesapeake Bay. Southeastern Archaeology 17 (1): 53–71.

Heuzé, Y., and J. Braga. 2008. Application of non-adult Bayesian dental age assessment methods to skeletal remains: the Spitalfields collection. Journal of Archaeological Science 35 (2): 368–375. http://dx.doi.org/10.1016/j.jas.2007.04.003

Higham, T.F.G., and P.L. Horn. 2000. Seasonal dating using fish otoliths: results from the Shag River Mouth Site, New Zealand. Journal of Archaeological Science 27: 439–375. http://dx.doi.org/10.1006/jasc.1999.0473

Hillard, R., and K. Walters. 2009. Prevalence, patterns, and effects of shell damage on Geukensia demissa in South Carolina estuarine habitats. Marine Biology 156: 2149–375. http://dx.doi.org/10.1007/s00227-009-1245-7

Hillman, G. 1984. Interpretation of archaeological plant remains: the application of ethnographic models from Turkey. In W. Van Zeist and W.A. Casparie (editors), Plants and ancient man: studies in paleoethnobotany: 1–42. Rotterdam: A.A. Balkans.

Hillman, R.E., N.W. Davis, and J. Wennemer. 1977. Abundance, diversity, and stability in shore-zone fish communities in an area of Long Island Sound affected by the thermal discharge of a nuclear power station. Estuarine and Coastal Marine Science 5 (3): 355–381. http://dx.doi.org/10.1016/0302-3524(77)90062-7

Hobson, K.A. 1999. Tracing origins and migration of wildlife using stable isotopes: a review. Oecologia 120: 314–326. http://dx.doi.org/10.1007/s004420050865

Hobson, K.A., H. Lormée, S.L. Van Wilgenburg, L.I. Wassenaar, and J.M. Boutin. 2009. Stable isotopes (δD) delineate the origins and migratory connectivity of harvested animals: the case of European woodpigeons. Journal of Applied Ecology 46: 572–581. http://dx.doi.org/10.1111/j.1365-2664.2009.01651.x

Hoefs, J. 1997. Stable isotope geochemistry. New York: Springer.

Hoese, H.D., and R.H. Moore. 1998. Fishes of the Gulf of Mexico: Texas, Louisiana, and adjacent waters. 2nd ed. College Station: Texas A&M Press.

Holland, A.F., and J.M. Dean. 1977. The biology of the stout razor clam Tagelus plebeius: II. Some aspects of the population dynamics. Chesapeake Science 18: 188–196. http://dx.doi.org/10.2307/1350860

Hollenbach, K.D. 2009. Foraging in the Tennessee River Valley: 12,500 to 8,000 years ago. Tuscaloosa: University of Alabama Press.

Howard, J.D., and R.W. Frey. 1985. Physical and biogenic aspects of backbarrier sedimentary sequences, Georgia coast, U.S.A. Marine Geology 63: 77–127. http://dx.doi.org/10.1016/0025-3227(85)90080-5

Hoyt, J.H. 1967. Barrier island formation. Geological Society of America Bulletin 78 (9): 1125–1136. http://dx.doi.org/10.1130/0016-7606(1967)78[1125:BIF]2.0.CO;2

Hoyt, J.H., and J.R. Hails. 1967. Pleistocene shoreline sediments in coastal Georgia: deposition and modification. Science 155: 1541–1543. http://dx.doi.org/10.1126/science.155.3769.1541

Hubbard, D.K., G. Oertel, and D. Nummedal. 1979. The role of waves and tidal currents in the development of tidal-inlet sedimentary structures and sand body geometry: examples from North Carolina, South Carolina, and Georgia. Journal of Sedimentary Petrology 49 (4): 1073–1092.

Hudson, J.H., E.A. Shinn, R.B. Halley, and B. Lidz. 1976. Sclerochronology: a tool for interpreting past environments. Geology 4 (6): 361–364. http://dx.doi.org/10.1130/0091-7613(1976)4<361:SATFIP>2.0.CO;2

Hufthammer, A.K., H. Høie, A. Folkvord, A.J. Geffen, C. Andersson, and U.S. Ninnemann. 2010. Seasonality of human site occupation based on stable oxygen isotope ratios of cod otoliths. Journal of Archaeological Science 37: 78–83. http://dx.doi.org/10.1016/j.jas.2009.09.001

Ingold, T. 1996. Growing plants and raising animals: an anthropological perspective on domestication. In D. Harris (editor), The origins and spread of agriculture and pastoralism in Eurasia: 12–24. London: UCL Press.

Irving, W.S. 1902. Brunswick and Glynn County, Georgia. Issued by the Board of Trade, Brunswick, GA.

Ishimaru, E., T. Umino, M. Yoneda, and I. Tayasu. 2006. Identification of origin of faunal remains: carbon and nitrogen isotope analysis of marine fishes. Mexico City, Mexico: International Council for Archaeozoology. Internet resource (http://www.alexandriaarchive.org/icaz/pdf/poster_ishimaru_etal.pdf), accessed on December 14, 2011.

Jassby, A.D.,W.J. Kimmerer, S.G. Monismith, C. Armor, J.E. Cloern, T.M. Powell, J.R. Schubel, and T.J. Vendlinski. 1995. Isohaline position as a habitat indicator for estuarine populations. Ecological Applications 5 (1): 272–289. http://dx.doi.org/10.2307/1942069

Jochim, M. 2006. The implications of inter-group food exchange for hunter-gatherer affluence and complexity. In C. Grier, J. Kim, and J. Uchiyama (editors), Beyond affluent foragers: rethinking hunter-gatherer complexity: 80–89. Oxford: Oxbow Books.

Johnson, A.S., H.O. Hillestad, S.F. Shanholtzer, and G.F. Shanholtzer. 1974. An ecological survey of the coastal region of Georgia. National Park Service Scientific Monograph Series 3.

Johnson, D.R., and W. Seaman, Jr. 1986. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (South Florida): spotted seatrout. U.S. Fish and Wildlife Service Biological Report 82 (11.43).

Jones, C.A. 2010. Mineralogy and seasonal growth of South Pacific mussel valves. Master’s thesis, University of Alabama, Tuscaloosa.

Jones, C.C., Jr. 1873. Antiquities of the southern Indians, particularly of the Georgia tribes. New York: D. Appleton.

Jones, D.C., C.T. Espenshade, and L. Kennedy. 1997. Archaeological investigations at 31ON190, Cape Island, Onslow County, North Carolina. Ms. on file (OSA # 4069), North Carolina Office of State Archaeology, Raleigh, NC.

Jones, D.S. 1980. Annual cycle of shell growth increment formation in two continental shelf bivalves and its paleoecologic significance. Paleobiology 6 (3): 331–340.

Jones, D.S., and I.R. Quitmyer. 1996. Marking time with bivalve shells: oxygen isotopes and season of annual increment formation. Palaios 11: 340–346. http://dx.doi.org/10.2307/3515244

Jones, D.S., and S.J. Gould. 1999. Direct measurement of age in fossil Gryphaea: the solution to a classic problem in heterochrony. Paleobiology 25 (2): 158–187.

Jones, D.S., M.A. Arthur, and D.J. Allard. 1989. Sclerochronological records of temperature and growth from shells of Mercenaria mercenaria from Narragansett Bay, Rhode Island. Marine Biology 102: 225–234. http://dx.doi.org/10.1007/BF00428284

Jones, D.S., I.R. Quitmyer, W.S. Arnold, and D.C. Marelli. 1990. Annual shell banding, age, and growth rate of the hard shell clams (Mercenaria spp.) from Florida. Journal of Shellfish Research 9 (1): 215–225.

Jones, D.S., I.R. Quitmyer, and C.F.T. Andrus. 2004. Seasonal shell growth and longevity in Donax variabilis from northeastern Florida: evidence from oxygen isotopes. Journal of Shellfish Research 23: 707–714.

Jones, D.S., I.R. Quitmyer, and C.F.T. Andrus. 2005. Oxygen isotopic evidence for greater seasonality in Holocene shells of Donax variabilis from Florida. Palaeogeography, Palaeoclimatology, Palaeoecology 228: 96–108. http://dx.doi.org/10.1016/j.palaeo.2005.03.046

Jones, G.D. 1978. The ethnohistory of the Guale coast through 1684. In D. H. Thomas, G.D. Jones, R.S. Durham, and C.S. Larsen, The anthropology of St. Catherines Island. 1. Natural and cultural history. Anthropological Papers of the American Museum of Natural History 55 (2): 178–210.

Jones, G.D. 1980. Guale Indians of the southeastern United States coast. In J.D. Howard, C.B. DePratter, and R.W. Frey (editors), Georgia Geological Survey Guidebook: 215–224.

Jones, G.E.M. 1984. Interpretation of archaeological plant remains: ethnographic models from Greece. In W. Van Zeist and W.A. Casparie (editors), Plants and ancient man: studies in paleoethnobotany: 43–62. Rotterdam: A.A. Balkans.

Jones, J.B., and S.E. Campana. 2009. Stable oxygen isotope reconstruction of ambient temperature during the collapse of a cod (Gadus morhua) fishery. Ecological Applications 19 (6): 1500–1514. http://dx.doi.org/10.1890/07-2002.1

Jones, K.B., G.W.L. Hodgins, D. Dettman, C.F. T. Andrus, A. Nelson, A., and M.F. Etayo-Cadavid. 2007. Seasonal variations in Peruvian marine reservoir age from pre-bomb Argopecten purpuratus shell carbonate. Radiocarbon 49: 877–888.

Jones, K.B., G.W.L. Hodgins, C.F.T. Andrus, and M.F. Etayo-Cadavid. 2010a. Modeling molluscan marine reservoir ages in a variable-upwelling environment. Palaios 25: 126–131. http://dx.doi.org/10.2110/palo.2009.p09-050r

Jones, K.B., G.W.L. Hodgins, M.F. Etayo-Cadavid, C.F.T. Andrus, and D.H. Sandweiss. 2010b. Centuries of marine radiocarbon reservoir age variation within archaeological Mesodesma donacium shells from southern Peru. Radiocarbon 52 (3): 1207–1214.

Jones, T.L. and D.J. Kennett. 1999. Late Holocene sea temperatures along the central California coast. Quaternary Research 51: 74–82. http://dx.doi.org/10.1006/qres.1998.2000

Jones, T.L., D.J. Kennett, J.P. Kennett, and B.F. Codding. 2008. Seasonal stability in Late Holocene shellfish harvesting on the central California coast. Journal of Archaeological Science 35 (8): 2286–2294. http://dx.doi.org/10.1016/j.jas.2008.03.002

Jorgenson, S.C., and G.L. Miller. 1968. Length relations of some marine fishes from coastal Georgia. Brunswick, GA: Bureau of Commercial Fishes Biological Laboratory Contribution 93.

Kaplan, H., and K. Hill. 1992. The evolutionary ecology of food acquisition. In E.A. Smith and B. Winterhalder (editors), Evolutionary ecology and human behavior: 167–202. New York: Aldine de Gruyter.

Keene, D.A. 2004. Reevaluating Late Prehistoric coastal subsistence and settlement strategies: new data from Grove’s Creek Site, Skidaway Island, Georgia. American Antiquity 69 (4): 671–688. http://dx.doi.org/10.2307/4128443

Kelly, R.L. 1992. Mobility/sedentism: concepts, archaeological measures, and effects. Annual Review of Anthropology 21: 43–66. http://dx.doi.org/10.1146/annurev.an.21.100192.000355

Kelly, R.L. 1995. The foraging spectrum: diversity in hunter-gatherer lifeways. Washington, DC: Smithsonian Institution Press.

Kelly, R.L., L. Poyer, and B. Tucker. 2005. An ethnoarchaeological study of mobility, architectural investment, and food sharing among Madagascar’s Mikae. American Anthropologist 107 (3): 403–416. http://dx.doi.org/10.1525/aa.2005.107.3.403

Kemp, P. and M.B. Bertness. 1984. Snail shape and growth rates: evidence for plastic shell allometry in Littorina littorea. Proceedings of the National Academy of Sciences of the United States of America 81: 811–813. http://dx.doi.org/10.1073/pnas.81.3.811

Kennedy, B.P., C.P. Chamberlain, J.D. Blum, K.H. Nislow, and C.L. Folt. 2005. Comparing naturally occurring stable isotopes of nitrogen, carbon, and strontium as markers for the rearing locations of Atlantic salmon (Salmo salar). Canadian Journal of Fisheries and Aquatic Science 62: 48–57. http://dx.doi.org/10.1139/f04-184

Kennett, D.J., and J.P. Kennett. 2000. Competitive and cooperative responses to climatic instability in coastal southern California. American Antiquity 65: 379–395. http://dx.doi.org/10.2307/2694065

Kennett, D. J., and B. Voorhies. 1995. Middle Holocene periodicities in rainfall inferred from oxygen and carbon isotopic fluctuations in prehistoric tropical estuarine mollusc shells. Archaeometry 37: 157–170. http://dx.doi.org/10.1111/j.1475-4754.1995.tb00734.x

Kennett, D. J., and B. Voorhies. 1996. Oxygen isotopic analysis of archaeological shells to detect seasonal use of wetlands on the southern Pacific coast of Mexico. Journal of Archaeological Science 23: 689–704. http://dx.doi.org/10.1006/jasc.1996.0065

Kennett, D.J., B.L. Ingram, J. Erlandson, and P. Walker. 1997. Evidence for temporal fluctuations of marine radiocarbon reservoir ages in the Santa Barbara Channel region, California. Journal of Archaeological Science 24: 1051–1059. http://dx.doi.org/10.1006/jasc.1996.0184

Kennett, D.J., B.L Ingram, J.R. Southon, and K. Wise. 2002. Differences in 14C age between stratigraphically associated charcoal and marine shell from the Archaic period site of Kilometer 4, southern Peru: old wood or old water? Radiocarbon 44 (1): 53–58.

Kennett, D.J., B.J. Culleton, B. Voorhies, and J. Southon. 2011. Bayesian analysis of high precision AMS 14C dates from a prehistoric Mexican shellmound. Radiocarbon.

Kennish, M.J. 1980. Shell microgrowth analysis: Mercenaria mercenaria as type example for research in population dynamics. In D.D. Rhoads and R.A. Lutz (editors), Skeletal growth of aquatic organisms: 255–294. New York: Plenum Press.

Kennish, M.J., and R.K. Olsson. 1975. Effects of thermal discharges on the microstructural growth of Mercenaria mercenaria. Environmental Geology 1: 41–64. http://dx.doi.org/10.1007/BF02426940

Kent, B. 1988. Making dead oysters talk: techniques for analyzing oysters from archaeological sites. St. Mary’s City: Maryland Historical Trust.

Kent, B.W. 1992. Making dead oysters talk: techniques for analyzing oysters from 595 archaeological sites. Crownsville: Maryland Historical and Cultural Publications.

Kenward, H., and A. Hall. 1997. Enhancing bioarchaeological interpretation using indicator groups: stable manure as a paradigm. Journal of Archaeological Science 24: 663–673. http://dx.doi.org/10.1006/jasc.1996.0149

Killingley, J.S., and W.H. Berger. 1979. Stable isotopes in a mollusk shell: detection of upwelling events. Science 205: 186–188. http://dx.doi.org/10.1126/science.205.4402.186

Kim, S.T., A. Mucci, and B. Taylor. 2007. Phosphoric acid fractionation factors for calcite and aragonite between 25 and 75 °C: revisited. Chemical Geology 246: 135–146. http://dx.doi.org/10.1016/j.chemgeo.2007.08.005

Kirby, M.X., T.M. Soniat, and H.J. Spero. 1998. Stable isotope sclerochronology of Pleistocene and recent oyster shells (Crassostrea virginica). Palaois 13: 560–569. http://dx.doi.org/10.2307/3515347

Klein, M.J. 1999. Shell midden archaeology: gender, labor, and stone artifacts. In N.L. Wicker and B. Arnold (editors), From the ground up: beyond gender theory in archaeology: 143–154. BAR International Series 812.

Koch, P.L. 2007. Isotopic study of the biology of modern and fossil vertebrates. In R. Michener and K. Lajtha (editors), Stable isotopes in ecology and environmental science, 2nd ed.: 99–154. Malden, MA: Blackwell. http://dx.doi.org/10.1002/9780470691854.ch5

Koike, H. 1975. The use of daily and annual growth lines of the clam Meretrix lusoria in estimating seasons of Jomon period shell gathering. In R.P. Suggate and M.M. Cresswell (editors), Quaternary studies: 189–193. Wellington: Royal Society of New Zealand.

Koike, H. 1979. Seasonal dating and the valve-pairing technique in shell-midden analysis. Journal of Archaeological Science 6 (1): 63–74. http://dx.doi.org/10.1016/0305-4403(79)90033-5

Kraeuter, J.N., and M. Castagna. 2001. Biology of the hard clam. New York: Elsevier.

Kroeber, A.L. 1925. Handbook of the Indians of California. Bureau of American Ethnology Bulletin 78.

Lambert, C. 2007. Comings and goings on the seashore. No Wake Zone 2 (12): 2.

Larsen, C.S., and D.H. Thomas. 1982. The anthropology of St. Catherines Island: 4. The St. Catherines period mortuary complex. Anthropological Papers of the American Museum of Natural History 57 (4): 271–342.

Larson, L.H., Jr. 1969. Aboriginal subsistence technology on the Southeastern Coastal Plain during the late prehistoric period. Ms., University of Michigan, Department of Anthropology.

Larson, L.H., Jr. 1978. Historic Guale Indians of the Georgia coast and the impact of the Spanish mission effort. In J. Milanich and S. Proctor (editors), Tacachale: essays of the Indians of Florida and southeastern Georgia during the historic period: 120–140. Gainesville: University of Florida Press.

Larson, L.H., Jr. 1980. Aboriginal subsistence technology on the Southeastern Coastal Plain during the late prehistoric period. Gainesville: University of Florida Press.

Lassuy, D.R. 1983. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): Atlantic croaker. U.S. Fish and Wildlife Service, Biological Report 82 (11.3).

Laufer, B. 1913. The relationship of archeology to ethnology: remarks. American Anthropologist 15: 573–577.

Lécuyer, C., B. Reynard, and F. Martineau. 2004. Stable isotope fractionation between mollusc shells and marine waters from Martinique Island. Chemical Geology 213: 293–305. http://dx.doi.org/10.1016/j.chemgeo.2004.02.001

Lee, C.H., I.R. Quitmyer, C.T. Espenshade, and R.E. Johnson. 1984. Estuarine adaptations during the Late Prehistoric period: archaeology of two shell midden sites on the St. Johns River. Pensacola, FL: University of West Florida, Office of Cultural and Archaeological Research, Report of Investigations 5.

Lee, R.B., and R. Daly (editors). 1999. The Cambridge encyclopedia of hunters and gatherers. Cambridge: Cambridge University Press.

Lee, R.B., and I. DeVore. 1968. Problems in the study of hunters and gatherers. In R.B. Lee and I. DeVore (editors), Man the hunter: 3–12. Chicago: Aldine-Atherton.

Lemonier, P. 1986. The study of material culture today: toward an anthropology of technical systems. Journal of Anthropological Archaeology 5 (2): 147–186. http://dx.doi.org/10.1016/0278-4165(86)90012-7

Leroi-Gourhan, A. 1964. Le geste et la parole, tome 1: technique et language. Paris: Albin Michel.

Leroi-Gourhan, A. 1993. Gesture and speech (Le geste et la parole). Translated from French by Anna Bostock Berger. Cambridge: MIT Press.

Levin, L.A., D.F. Boesch, A. Covich, C. Dahm, C. Erseus, K.C. Ewel, R.T. Kneib, A. Moldenke, M.A. Palmer, P. Snelgrove, D. Strayer, and J.M. Weslawski. 2001. The function of marine critical transition zones and the importance of sediment biodiversity. Ecosystems
4 (5): 430–451. http://dx.doi.org/10.1007/s10021-001-0021-4

Lightfoot, K.G., and O. Parrish. 2009. California Indians and their environment: an introduction. Berkeley: University of California Press.

Liu, K.-B. 2004. Paleotempestology: principles, methods, and examples from Gulf coast lake sediments. In R.J. Murnane and K.-B. Liu (editors), Hurricanes and typhoons: past, present, and future: 13–95. New York: Columbia University Press.

Livingston, R.J. 1975. Impact of Kraft pulp-mill effluents on estuarine and coastal fishes in Apalachee Bay, Florida, USA. Marine Biology 32 (1): 19–48. http://dx.doi.org/10.1007/BF00395158

Livingston, R.J. 1982. Trophic organization of fishes in a coastal seagrass system. Marine Ecology Progress Series 7: 1–12. http://dx.doi.org/10.3354/meps007001

Livingston, R.J. 1985. Organization of fishes in coastal seagrass system: the response to stress. In A. Yáñez-Arancibia (editor), Fish community ecology in estuaries and coastal lagoons: towards an ecosystem integration: 367–382. Mexico City, Mexico: UNAM Press.

Loftfield, T.C. 1979. Excavations at 31 Onv 33: a Late Woodland seasonal village (OSA # 915). Manuscript on file, Office of State Archaeology, Raleigh, NC.

Lomovaskya, B.L., J.L. Gutiérrez, and O.O. Iribarnea. 2005. Identifying repaired shell damage and abnormal calcification in the stout razor clam Tagelus plebeius as a tool to investigate its ecological interactions. Journal of Sea Research 54: 163–175. http://dx.doi.org/10.1016/j.seares.2005.01.004

Lowerre-Barbieri, S.K., L.R. Barbieri, J.R. Flanders, A.G. Woodward, C.F. Cotton, and K. Knowlton. 2008. Use of passive acoustics to determine red drum spawning in Georgia waters. Transactions of the American Fisheries Society 137 (2): 562–575. http://dx.doi.org/10.1577/T04-226.1

Luby, E.M., C.D. Drescher, and K.G. Lightfoot. 2006. Shell mounds and mounded landscapes in the San Francisco Bay area: an integrated approach. Journal of Island and Coastal Archaeology 1: 191–214. http://dx.doi.org/10.1080/15564890600935365

Lutz, R.A. and D.C. Rhoads.1977. Anaerobiosis and a theory of growth line formation. Science 198 (4323): 1222–1227. http://dx.doi.org/10.1126/science.198.4323.1222

Lynch, A.H., J. Hamilton, and R.E.M. Hedges. 2008. Where the wild things are: aurochs and cattle in England. Antiquity 82 (318): 1025–1039.

MacKenzie, C.L., Jr. 2008. History of the bay scallop, Argopecten irradians, fisheries and habitats in eastern North America, Massachusetts through northeastern Mexico. Marine Fisheries Review 70 (3–4): 1–5.

Malinowski, S.R. 1985. The population ecology of the hard clam, Mercenaria mercenaria, in eastern Long Island Sound. Ph.D. dissertation. University of Connecticut, Storrs.

Mannino, M.A., and K.D. Thomas. 2002. Depletion of a resource? the impact of prehistoric human foraging on intertidal mollusc communities and its significance for human settlement, mobility and dispersal. World Archaeology 33 (3): 452–474. http://dx.doi.org/10.1080/00438240120107477

Mannino M.A., B.F. Spiro, and K.D. Thomas. 2003. Sampling shells for seasonality: oxygen isotope analysis on shell carbonates of the inter-tidal gastropod Monodonta lineata (da Costa) from populations across its modern range and from a Mesolithic site in southern Britain. Journal of Archaeological Science 30: 667–679. http://dx.doi.org/10.1016/S0305-4403(02)00238-8

Mannino M.A., K.D. Thomas, M.J. Leng, M. Piperno, S. Tusa, and A. Tagliacozzo. 2007. Marine resources in the Mesolithic and Neolithic at the Grotta dell’Uzzo (Sicily): evidence from isotope analyses of marine shells. Archaeometry 49: 117–133. http://dx.doi.org/10.1111/j.1475-4754.2007.00291.x

Marelli, D.C., and W.S. Arnold. 2001. Shell morphologies of bay scallops, Argopecten irradians, from extant and prehistoric populations from the Florida Gulf Coast: implications for the biology of past and present metapopulations. Journal of Archaeological Science 28: 577–586. http://dx.doi.org/10.1006/jasc.2000.0565

Marquardt, W.H. 1996. Four discoveries: environmental archaeology in southwest Florida. In E.J. Reitz, L.A. Newsom, and S.J. Scudder (editors), Case studies in environmental archaeology: 17–34. New York: Plenum Press.

Marquardt, W.H. 2010a. Mounds, middens, and rapid climate change during the Archaic-Woodland transition in the southeastern United States. In D.H. Thomas and M.C. Sanger (editors and contributors), Trend, tradition, and turmoil: what happened to the southeastern Archaic? Anthropological Papers of the American Museum of Natural History 93: 253–271.

Marquardt, W.H. 2010b. Shell mounds in the Southeast: middens, monuments, temple mounds, rings, or works? American Antiquity 75 (3): 551–570.

Marrinan, R.A. 1975. Molluscs, ceramics and sedentism: the Late Archaic period on the Georgia Coast. Ph.D. dissertation, Department of Anthropology, University of Florida, Gainesville.

Marrinan, R.A. 2010. Two Late Archaic period shell rings, St. Simon’s Island, Georgia. In D.H. Thomas and M.C. Sanger (editors and contributors), Trend, tradition, and turmoil: what happened to the southeastern Archaic? Anthropological Papers of the American Museum of Natural History 93: 71–102.

Marshall, R.R. 1986. A compilation of materials relating to the proposed Stump Sound archaeological district, Onslow County, North Carolina (OSA #2193). Manuscript on file, Office of State Archaeology, Raleigh, NC.

Martin, G.B., and S.R. Thorrold. 2005. Temperature and salinity effects on magnesium, manganese, and barium incorporation in otoliths of larval and early juvenile spot Leiostomus xanthurus. Marine Ecology Progress Series 293: 223–232. http://dx.doi.org/10.3354/meps293223

Martin, K.L.M., R. C.V. Winkle, J.E. Drais, and H. Lakisic. 2004. Beach-spawning fishes, terrestrial eggs, and air breathing. Physiological and Biochemical Zoology 77 (5): 750–759. http://dx.doi.org/10.1086/421755

Martin-Mora, E., E.C. James, and A.W. Stoner. 1995. Developmental plasticity in the shell of the queen conch Strombus gigas. Ecology 76: 981–994.

Matthews, J.H. 1928. Fisheries of the south Atlantic and Gulf states. Economic Geography 4 (4): 323–348. http://dx.doi.org/10.2307/140392

McClanahan, T.R., and J.E. Cinner. 2008. A framework for adaptive gear and ecosystem-based management in the artisanal coral reef fishery of Papua New Guinea. Aquatic Conservation: Marine and Freshwater Ecosystems 18: 493–507. http://dx.doi.org/10.1002/aqc.874

McConnaughey, T.A., and D.P. Gillikin.2008. Carbon isotopes in mollusk shell carbonates. Geo-Marine Letters 28: 287–299. http://dx.doi.org/10.1007/s00367-008-0116-4

McLusky, D.S., and M. Elliott. 2004. The estuarine ecosystem: ecology, threats, and management. Oxford University Press, Oxford. http://dx.doi.org/10.1093/acprof:oso/9780198525080.001.0001

Meehan, B. 1982. Shell bed to shell midden. Canberra: Australian Institute of Aboriginal Studies.

Messner, T.C. 2011. Acorns and bitter roots: starch grain research in the prehistoric Eastern Woodlands. Tuscaloosa: University of Alabama Press.

Milton, K. 1993. Diet and primate evolution. Scientific American 269 (2): 86–93. http://dx.doi.org/10.1038/scientificamerican0893-86

Monks, G.G. 1981. Seasonality studies. In M.B. Schiffer (editor), Advances in archaeological method and theory 4: 177–240. New York: Academic Press.

Mook, W.G., and J.C. Vogel. 1968. Isotopic equilibrium between shells and their environment. Science 159 (3817): 874–875. http://dx.doi.org/10.1126/science.159.3817.874

Morales Muñiz, A. 1998. The mobile faunas: reliable seasonal indicators for archaeozoologists? In T.R. Rocek and O. Bar-Yosef (editors), Seasonality and sedentism: archaeological perspectives from Old and New World sites: 25–39. Peabody Museum of Archaeology and Ethnology Bulletin No. 6, Cambridge, MA: Harvard University.

Muncy, R.J., and W.M. Wingo. 1983. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): sea catfish and gafftopsail catfish. U.S. Fish and Wildlife Service, Biological Report 82 (11.5).

Munson, P.J. 1986. Hickory silvaculture: a subsistence revolution in the prehistory of eastern North America. Paper presented at the Conference on Emergent Horticultural Economies of the Eastern Woodlands. Center for Archaeological Investigations. Urbana: Southern Illinois University.

Murray, G., B. Neis, and J.P. Johnsen. 2006. Lessons learned from reconstructing interactions between local ecological knowledge, fisheries science, and fisheries management in the commercial fisheries of Newfoundland and Labrador, Canada. Human Ecology 34 (4): 549–571. http://dx.doi.org/10.1007/s10745-006-9010-8

Nagelkerken, I., and G. van der Velde. 2004. Are Caribbean mangroves important feeding grounds for juvenile reef fish from adjacent seagrass beds? Marine Ecology Progress Series 274: 143–151. http://dx.doi.org/10.3354/meps274143

Nelson, D.M., E.A. Irlandi, L.R. Settle, M.E. Monaco, and L. Coston-Clements. 1991. Distribution and abundance of fishes and invertebrates in Southeast estuaries. ELMR Report 9. Silver Spring, MD: NOAA/NOS Strategic Environmental Assessments Division.

Nishimura, A. 1975. Cultural and social change in the modes of ownership of stone tidal weirs. In R. W. Casteel and G. I. Quimby (editors), Maritime adaptations of the Pacific: 77–88. The Hague: Mouton Publishers.

O’Brien, D.M., and D.H. Thomas. 2008. The molluscan incremental sequence. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 475–497.

O’Brien, M.J., and R.L. Lyman. 1999. Seriation, stratigraphy, and index fossils: the backbone of archaeological dating. New York: Kluwer Academic.

Odum, E.P., and G.W. Barrett. 2005. Fundamentals of ecology. 5th ed. Belmont, California: Thomson Brooks/Cole.

Odum, H.T. 1971. Economy, power, and society. New York: Wiley-Interscience.

Oertel, G.F. 1979. Barrier island development during the Holocene recession, southeastern United States. In S.P. Leatherman (editor), Barrier islands: from the Gulf of St. Lawrence to the Gulf of Mexico: 273–290. New York: Academic Press.

Orr, K.L. 2007. Coastal Weeden Island subsistence adaptations: zooarchaeological evidence from Bayou St. John (1BA21), Alabama. Ph.D. dissertation, Department of Anthropology, University of Georgia, Athens.

Osborn, A.J. 1977. Strandloopers, mermaids, and other fairy tales: ecological determinants of marine resource utilization—the Peruvian case. In L.R. Binford (editor), For theory building in archaeology: 157–250. New York: Academic Press.

Owen, R., H. Kennedy, and C. Richardson. 2002. Isotopic partitioning between scallop shell calcite and seawater: effect of shell growth rate. Geochimica et Cosmochimica Acta 66: 1727–1737. http://dx.doi.org/10.1016/S0016-7037(01)00882-1

Pannella, G. 1971. Fish otoliths: daily growth layers and periodical patterns. Science 173: 1124–1126. http://dx.doi.org/10.1126/science.173.4002.1124

Pannella, G. 1980. Growth patterns in fish sagittae. In D.C. Rhoads and R.A. Lutz (editors), Skeletal growth of aquatic organisms: biological records of environmental change: 519–560. New York: Plenum Press.

Parnell, A.C., J. Haslett, J.R.M. Allen, C.E. Buck, and B. Huntley. 2008. A flexible approach to assessing synchroneity of past events using Bayesian reconstructions of sedimentation history. Quaternary Science Reviews 27: 1872–1885. http://dx.doi.org/10.1016/j.quascirev.2008.07.009

Parsons, A. 2008. The Grand Shell Ring: a study of site seasonality, hard clam exploitation, and resource scheduling. Master’s thesis. Florida State University Tallahassee.

Payne, T.M., and B.H. Dahlin. 1987. A phase I archaeological survey 31BF115 and 31BF117 and a phase II archaeological survey 31BF115 Texasgulf, Bath Creek, North Carolina (OSA # 2208). Ms. on file, Office of State Archaeology, Raleigh, NC.

Peacock, E., and J.L. Seltzer. 2008. A comparison of multiple proxy data sets for paleoenvironmental conditions as derived from freshwater bivalve (Unionid) shell. Journal of Archaeological Science 35: 2557–2565. http://dx.doi.org/10.1016/j.jas.2008.04.006

Peacock, E., W.R. Haag, and M.L. Warren, Jr. 2004. Prehistoric decline in freshwater mussels coincident with the advent of maize agriculture. Conservation Biology 19 (2): 547–551. http://dx.doi.org/10.1111/j.1523-1739.2005.00036.x

Pearson, C.E. 1977. Analysis of Late Prehistoric settlement on Ossabaw Island, Georgia. University of Georgia, Laboratory of Archaeology, Series Report 12.

Petruso, K.M., and J.M. Wickens. 1984. The acorn in aboriginal subsistence in eastern North America: a report on miscellaneous experiments. In P.J. Munson (editor), Experiments and observations on aboriginal wild plant food utilization in eastern North American: 360–378. Prehistoric Research Series VI (2). Indianapolis: Indiana Historical Society.

Pollard, M., C. Batt, B. Stern, and S.M.M. Young. 2007. Analytical chemistry in archaeology. Cambridge: Cambridge University Press. http://dx.doi.org/10.1017/CBO9780511607431

Porter, H.J., L.A. Howie, and R.B. Deriso. 1979. Morphometric character variation in Boonea impressa (Say) and B. seminuda (C.B. Adams)—family Pyramidellae. Bulletin of the American Malacological Union for 1979: 43–48.

Powell, E.N., M.E. White, E.A. Wilson, and S.M. Ray. 1987. Change in host preference with age in the ectoparasitic pyramidellid snail Boonea impressa (Say). Journal of Molluscan Studies 53: 285–286. http://dx.doi.org/10.1093/mollus/53.3.285

Power, A. J., C.J. Sellers, and R.L. Walker. 2009. Growth and sexual maturity of the knobbed whelk, Busycon carica (Gmelin, 1791), from a commercially harvested population in coastal Georgia. Occasional Papers of the University of Georgia Marine Extension Service 4.

Price, S.E. 2008. Phase III archaeology at Plash Island archaeological site 1BA134 in Baldwin County, Alabama. Mobile: University of South Alabama.

Price, S.E., and G.A. Waselkov. 2009. Bone and shell tools. In S.E. Price (editor), Archaeology at Orange Beach: phase III data recovery at 1BA21, the Bayou St. John site, Orange Beach, Baldwin County, Alabama: 144–169. Mobile, AL: Center for Archaeological Studies, University of South Alabama. Internet resource (http://www.usouthal.edu/archaeology/temp-file-access/001.pdf), accessed on December 14, 2011.

Quitmyer, I.R. 2003. Zooarchaeological remains from Bottle Creek. In I.W. Brown (editor), Bottle Creek: a Pensacola culture site in south Alabama: 130–155. Tuscaloosa: University of Alabama Press.

Quitmyer I.R., and D.S. Jones. 1992. Calendars of the coast: seasonal growth increment patterns in shells of modern and archaeological southern quahogs, Mercenaria campechiensis, from Charlotte Harbor, Florida. In W.H. Marquardt, Culture and the environment in the domain of the Calusa: 247–262. Gainesville, Institute of Archaeology and Paleoenvironmental Studies.

Quitmyer, I.R., and D.S. Jones. 2000. The over exploitation of hard clams (Mercenaria spp.) from five archaeological sites in the southeastern United States. Florida Anthropologist 53 (2–3): 160–167.

Quitmyer, I.R., and M.J. LeFebvre. 2004. The zooarchaeology of Ribault Clubhouse Midden (8DU76), Duval County, Florida. Ms. on file, Environmental Archaeology Laboratory, Florida Museum of Natural History, University of Florida, Gainesville.

Quitmyer, I.R., and E.J. Reitz. 2006. Marine trophic levels targeted between a.d. 300 and 1500 on the Georgia coast, USA. Journal of Archaeological Science 33: 806–822.

Quitmyer, I.R., H.S. Hale, and D.S. Jones. 1985. Paleoseasonality determination based on incremental shell growth in the hard clam, Mercenaria mercenaria, and its implications for future analysis of three Georgia coastal shell middens. Southeastern Archaeology 4 (1): 27–40.

Quitmyer, I.R., D.S. Jones, and W.S. Arnold. 1997. The sclerochronology of hard clams, Mercenaria spp., from the south-eastern U.S.A.: a method of elucidating the zooarchaeological records of seasonal resource procurement and seasonality in prehistoric shell middens. Journal of Archaeological Science 24 (9): 825–840. http://dx.doi.org/10.1006/jasc.1996.0163

Quitmyer, I.R., D.S. Jones, and C.F.T. Andrus. 2005. Seasonal collection of coquina clams (Donax variabilis Say, 1822) during the Late Archaic and St. Johns periods in coastal northeast Florida. In D.E. Bar-Yosef Mayer (editor), Archaeomalacology: molluscs in former environments of human behavior. Proceedings of the Archaeomalacology Symposium of the 9th International Council for Zooarchaeology: 18–28. Oxford: Oxbow Press.

Raab, L.M. 1996. Debating prehistory in coastal southern California: resource intensification versus political economy. Journal of California and Great Basin Anthropology 18 (1): 64–80.

Reagan, R.E. 1985. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): red drum. U.S. Fish and Wildlife Service. Biological Report 82 (11.36).

Redman, C.L., J.M. Grove, and L.H. Kuby. 2004. Integrating social science into the Long-Term Ecological Research (LTER) network: social dimensions of ecological change and ecological dimensions of social change. Ecosystems 7: 161–171. http://dx.doi.org/10.1007/s10021-003-0215-z

Reis, R.R., and J.M. Dean. 1981. Temporal variation in the utilization of an intertidal creek by the bay anchovy (Anchoa mitchilli). Estuaries 4: 16–23. http://dx.doi.org/10.2307/1351539

Reitz, E.J. 1982. Vertebrate fauna from four coastal Mississippian sites. Journal of Ethnobiology 2: 39–61.

Reitz, E.J. 1988. Evidence for coastal adaptations in Georgia and South Carolina. Archaeology of Eastern North America 16: 137–158.

Reitz, E.J. 1991. Animal use and culture change in Spanish Florida. In P.J. Crabtree and K. Ryan (editors), Animal use and culture change: 62–77. Philadelphia: University of Pennsylvania, Museum of Archaeology and Anthropology Research Papers in Science and Archaeology, MASCA 8.

Reitz, E.J. 1994. Zooarchaeological analysis of a free African community: Gracia Real de Santa Teresa de Mose. Historical Archaeology 28 (1): 23–40.

Reitz, E.J. 2004. “Fishing down the food web”: a case study from St. Augustine, Florida, USA. American Antiquity 69 (1): 63–83. http://dx.doi.org/10.2307/4128348

Reitz, E.J. 2008. Nonhuman vertebrate remains. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 615–665.

Reitz, E.J., and J. Dukes. 2008. Change and stability in vertebrate use between the Irene Period and the Mission period: nonhuman vertebrate remains from Meeting House Field and Fallen Tree. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 778–798.

Reitz, E.J., and I.R. Quitmyer. 1988. Faunal remains from two coastal Georgia Swift Creek sites. Southeastern Archaeology 7 (2): 95–108.

Reitz, E.J., and C.M. Scarry. 1985. Reconstructing historic subsistence with an example from sixteenth-century Spanish Florida. Society for Historical Archaeology 3 (special publications).

Reitz, E.J., and E.S. Wing. 1999. Zooarchaeology. Cambridge: Cambridge University Press.

Reitz, E.J., and E.S. Wing. 2008. Zooarchaeology. 2nd ed. Cambridge: Cambridge University Press.

Reitz, E.J., C.F.T. Andrus, and D.H. Sandweiss. 2008. Ancient fisheries and marine ecology of coastal Peru. In T.C. Rick and J.M. Erlandson (editors), Human impacts on ancient marine ecosystems: a global perspective: 125–145. Berkeley: University of California Press.

Reitz. E.J., I.R. Quitmyer, and R.A. Marrinan. 2009. What are we measuring in the zooarchaeological record of prehispanic fishing strategies in the Georgia Bight, USA? Journal of Island and Coastal Archaeology 4: 2–36. http://dx.doi.org/10.1080/15564890802349894

Reitz, E.J., B. Pavao-Zuckerman, D.C. Weinand, and G.A. Duncan. 2010. Mission and Pueblo of Santa Catalina de Guale, St. Catherines Island, Georgia: a comparative zooarchaeological analysis. Anthropological Papers of the American Museum of Natural History 91: 1–275.

Rhoads, D.C., and R.A. Lutz (editors). 1980. Skeletal growth of aquatic organisms. New York: Plenum Press.

Rhoads, D.C., and G. Pannella. 1970. The use of molluscan shell growth patterns in ecology and paleoecology. Lethaia 3: 143–161. http://dx.doi.org/10.1111/j.1502-3931.1970.tb01854.x

Rice, M.A., and J.A. Pechenik. 1992. A review of the factors influencing the growth of the northern quahog, Mercenaria mercenaria (Linnaeus, 1758). Journal of Shellfish Research 11: 279–287.

Rice, M.A., C. Hickox, and I. Zehra. 1989. Effects of intensive fishing effort on the population structure of quahogs, Mercenaria mercenaria (Linnaeus 1758), in Narragansett Bay. Journal of Shellfish Research 8: 345–354.

Rich, F.J., A. Vega, and F.J. Vento. 2011. Evolution of Late Pleistocene-Holocene climates and environments of St. Catherines Island and the Georgia Bight. In G.A. Bishop, H.B. Rollins, and D.H. Thomas (editors), Geoarchaeology of St. Catherines Island, Georgia. Anthropological Papers of the American Museum of Natural History 94: 67–77.

Rick, T.C., and J.M. Erlandson (editors). 2008. Human impacts on ancient marine ecosystems: a global perspective. Berkeley: University of California Press.

Robins, C.R., G.C. Ray, J. Douglass, R. Freund, National Audubon Society, and National Wildlife Federation. 1986. A field guide to Atlantic coast fishes of North America. Boston: Houghton Mifflin.

Rogers, S.G., T.E. Targett, and S.B. Vansant. 1984. Fish-nursery use in Georgia salt-marsh estuaries: the influence of springtime freshwater conditions. Transactions of the American Fisheries Society 113: 595–606. http://dx.doi.org/10.1577/1548-8659(1984)113<595:FUIGSE>2.0.CO;2

Ropes, J.W. 1987. Preparation of acetate peels of valves from the ocean quahog, Artica islandica, for age determinations. Washington, DC: U.S. Department of Commerce, NOAA Technical Report.

Rowley-Conwy, P. 1983. Sedentary hunters: the Ertebølle example. In G. Bailey (editor) Hunter-gatherer economy in prehistory: a European perspective: 111–126. Cambridge: Cambridge University Press.

Rowley-Conwy, P. 1998. Cemeteries, seasonality and complexity in the Ertebølle of southern Scandinavia. In M. Zvelebil, R. Dennell, and L. Domanska (editors), Harvesting the sea, farming the forest: 193–202. Sheffield, UK: Sheffield Academic Press.

Rozas, L.P., and T.J. Minello. 2001. Marsh terracing as a wetland restoration tool for creating fishery habitat. Wetlands 21 (3): 327–341. http://dx.doi.org/10.1672/0277-5212(2001)021[0327:MTAAWR]2.0.CO;2

Rozas, L.P., and R.J. Zimmerman. 2000. Small-scale patterns of nekton use among marsh and adjacent shallow nonvegetated areas of the Galveston Bay estuary, Texas (USA). Marine Ecology Progress Series 193: 217–239. http://dx.doi.org/10.3354/meps193217

Ruhl, D.L. 1993. Customs and traditions in new terrain: sixteenth and seventeenth century archaeobotanical data from La Florida. In C. M. Scarry (editor), Foraging and farming in the eastern woodlands: 255–283.

Ruhl, D.L. 2003. Imagining sixteenth and seventeenth century Native American and Hispanic transformations of the Georgia Bight landscapes. Bulletin of Florida Museum of Natural History 44 (1): 183–198.

Ruhl, D.L. 2008. Bridging the 20th and 21st centuries: St. Catherines Island archaeobotany from missions to shell rings. Paper presented at 65th Annual Meeting of the Southeastern Archaeological Conference, Charlotte, NC.

Russo, M. 1991. A method for the measurement of season and duration of oyster collection: two case studies from the prehistoric south-east U.S. Coast. Journal of Archaeological Science 18 (2): 205–221. http://dx.doi.org/10.1016/0305-4403(91)90049-U

Russo, M. 1998. Measuring sedentism with fauna: Archaic cultures along the southwest Florida coast. In T.R. Rocek and O. Bar-Yosef (editors), Seasonality and sedentism: archaeological perspectives from Old and New World sites. Peabody Museum of Archaeology and Ethnology, Harvard University, Peabody Museum Bulletin 6: 143–164.

Russo, M. 2004. Measuring shell rings for social inequality. In J.L. Gibson and P.J. Carr (editors), Signs of power: the rise of cultural complexity in the Southeast: 26–70. Tuscaloosa: University of Alabama Press.

Russo, M. 2006. Archaic shell rings of the southeast U.S. theme study. Tallahassee, FL: National Park Service, National Register of Historic Places, Southeastern Archaeological Center.

Russo, M. 2008. Late Archaic shell rings and society in the southeast U.S. SAA Archaeological Record 8 (5):18–22.

Russo, M., and G. Heide. 2001. Shell rings of the southeast U.S. Antiquity 75: 491–492.

Russo, M. and I.R. Quitmyer. 1996. Sedentism in coastal populations of south Florida. In E.J. Reitz, L.A. Newsom, and S.J. Scudder (editors), Case studies in environmental archaeology: 215–231. New York: Plenum Press.

Russo, M. and I.R. Quitmyer. 2008. Developing models of settlement for the Florida Gulf coast. In E.J. Reitz, C.M. Scarry, and S.J. Scudder (editors), Case studies in environmental archaeology, 2nd ed.: 235–254. New York, Plenum Press. http://dx.doi.org/10.1007/978-0-387-71303-8_12

Russo, M.A., and R. Saunders. 2008. Quahog (Mercenaria mercenaria) seasonality at Meeting House Field. In D.H. Thomas, Native American landscapes of St. Catherines Island, Georgia. II. The data. Anthropological Papers of the American Museum of Natural History 88: 715–726.

Sanger, M.C., and D.H. Thomas. 2010. The two rings of St. Catherines Island: some preliminary results from the St. Catherines and McQueen shell rings. In D.H. Thomas and M.C. Sanger (editors and contributors), Trend, tradition, and turmoil: what happened to the southeastern Archaic? Anthropological Papers of the American Museum of Natural History 93: 44–69.

Sassaman, K.E. 2004. Complex hunter-gatherers in evolution and history: a North American perspective. Journal of Anthropological Research 12: 227–280.

Sassaman, K.E. 2006. People of the shoals: Stallings culture of the Savannah River Valley. Gainesville: University Press of Florida.

Saul, B.M. 2002. Ichthyofaunal survey of St. Catherines Island, Report 2002. American Museum of Natural History, Division of Anthropology, ms. on file.

Saul, B.M. 2003. Ichthyofaunal survey of St. Catherines Island, Report 2003. American Museum of Natural History, Division of Anthropology, ms. on file.

Saul, B.M. 2004. Ichthyofaunal survey of St. Catherines Island, Report 2004. American Museum of Natural History, Division of Anthropology, ms. on file.

Saunders, J.W., R.D. Mandel, R.T. Saucier, et al. 1997. A mound complex in Louisiana 5400–5000 years before the present. Science 277 (5333): 1796–1799. http://dx.doi.org/10.1126/science.277.5333.1796

Saunders, R. 2000a. Stability and change in Guale Indian pottery a.d. 1300–1702. Tuscaloosa: University of Alabama Press.

Saunders, R. 2000b. The Guale Indians of the Lower Atlantic Coast: change and continuity. In B.G. McEwan (editor), Indians of the greater Southeast: historical archaeology and ethnohistory: 26–56. Gainesville: University of Florida Press.

Scarry, C.M. 2003. Patterns of wild plant utilization in the prehistoric Eastern Woodlands. In P. Minnis (editor), People and plants in ancient eastern North America: 50–104. Washington, DC: Smithsonian Institution Press.

Scarry, C.M. 2008. Crop husbandry practices in North America’s Eastern Woodlands. In E. Reitz, C.M. Scarry, and S. Scudder (editors), Case studies in environmental archaeology, 2nd ed.: 391–404. New York: Springer. http://dx.doi.org/10.1007/978-0-387-71303-8_20

Scarry, C.M., and R.A. Yarnell. 2006. Domestication of plants in the east. In D. Ubelaker (editor), Environment, origins, and population, volume 3 of the Handbook of North American Indians: 428–436. Washington DC: Smithsonian Institution Press.

Scarry, J.F., and C.M. Scarry. 1997. Subsistence remains from prehistoric North Carolina sites. Raleigh: North Carolina Office of State Archaeology. Internet resource (http://www.archaeology.ncdcr.gov/subsist/subsis.htm), accessed on December 14, 2011.

Schaefer, K. 2011. Prehistoric subsistence on the coast of North Carolina: an archaeobotanical study. Ph.D. dissertation, Department of Anthropology, University of North Carolina at Chapel Hill.

Schelske, C.L., and E.P. Odum. 1961. Mechanisms maintaining high productivity in Georgia estuaries. Proceedings of the Gulf and Caribbean Fisheries Institute 1961: 75–80.

Schöne, B.R. 2008. The curse of physiology—challenges and opportunities in the interpretation of geochemical data from mollusk shells. Geo-Marine Letters 28 (5–6): 269–285. http://dx.doi.org/10.1007/s00367-008-0114-6

Schöne, B.R., E. Dunca, H. Mutvei, and U. Norlund. 2004. A 217-year record of summer air temperature reconstructed from freshwater pearl mussels (M. margarifitera, Sweden). Quaternary Science Reviews 23: 1803–1816. http://dx.doi.org/10.1016/j.quascirev.2004.02.017

Schopmeyer, C.S. 1974. Seeds of woody plants. Agricultural Handbook 450. Washington, DC: United States Department of Agriculture.

Semon, A., G. Mahar, M.C. Sanger, M. Napolitano, S. Bergh, and E. Blair. 2008. Trip Report Spring 2008. Ms. on file, Nels Nelson North American Archaeology Lab, American Museum of Natural History, New York.

Shackleton, N.J. 1973. Oxygen isotope analysis as a means of determining season of occupation of prehistoric midden sites. Archaeometry 15 (1): 133–141. http://dx.doi.org/10.1111/j.1475-4754.1973.tb00082.x

Shennan, S. 1997. Quantifying archaeology. Edinburgh: University Press.

Shipek, F.C. 1989. An example of intensive plant husbandry: the Kumeyaay of southern California. In D. Harris and G. Hillman (editors), Foraging and farming: the evolution of plant exploitation: 159–170. Boston: Unwin Hyman.

Shumway, S.E. 1996. Natural environmental factors. In V.S. Kennedy, R. Newell, I.E. and A.F. Eble (editors), The eastern oyster: Crassostrea virginica: 467–503. College Park: Maryland Sea Grant College.

Silvano, R.A.M., P.F.L. MacCord, R.V. Lima, and A. Begossi. 2006. When does this fish spawn? Fishermen’s local knowledge of migration and reproduction of Brazilian coastal fishes. Environmental Biology of Fishes 76 (2–4): 371–386. http://dx.doi.org/10.1007/s10641-006-9043-2

Smith, B.D. 1992. The role of Chenopodium as a domesticate in premaize garden systems of the eastern United States. In B.D. Smith (editor), Rivers of change: 103–131. Washington, DC: Smithsonian Institution Press.

Smith, B.D. 2001. Low-level food production. Journal of Archaeological Research 9:1–43. http://dx.doi.org/10.1023/A:1009436110049

Smith, H.A. 1983. Determination of seasonality in archaeological sites through examination of fish otoliths: a case study. Journal of Field Archaeology 10: 498–500.

Smith, J.W., and C.A. Wenner. 1985. Biology of the southern kingfish in the South Atlantic Bight. Transactions of the American Fisheries Society 114: 356–366. http://dx.doi.org/10.1577/1548-8659(1985)114<356:BOTSKI>2.0.CO;2

Stahle, D.W., and M.K. Cleaveland. 1992. Reconstruction and analysis of spring rainfall over the southeastern U.S. for the past 1000 years. Bulletin of the American Meteorological Society 73: 1947–1961. http://dx.doi.org/10.1175/1520-0477(1992)073<1947:RAAOSR>2.0.CO;2

Stahle, D.W., M.K. Cleaveland, D.B. Blanton, M.D. Therrell, and D.A. Gay. 1998. The lost colony and Jamestown droughts. Science 280: 564–567. http://dx.doi.org/10.1126/science.280.5363.564

Stahle, D.W., E.R. Cook, M.D. Therrell, D.M. Meko, H.D. Grissino-Mayer, E. Watson, and B.H. Luckman. 2000. Tree-ring data document 16th century megadrought over North America. EOS, Transactions of the American Geophysical Union 81 (12): 212, 125.

Stark, M.T. 1998. Technical choices and social boundaries in material culture patterning: an introduction. In M.T. Stark (editor), The archaeology of social boundaries: 1–11. Washington DC: Smithsonian Institution Press.

Steele, J. 2010. Radiocarbon dates as data: quantitative strategies for estimating colonization front speeds and event densities. Journal of Archaeological Science 37: 2017–2030. http://dx.doi.org/10.1016/j.jas.2010.03.007

Steier, P., and W. Rom. 2000. The use of Bayesian statistics for 14C dates of chronologically ordered samples: a critical analysis. Radiocarbon 42: 183–198.

Stein, J.K. 1992. Interpreting stratification of a shell midden. In J.K. Stein (editor), Deciphering a shell midden: 71–93. San Diego: Academic Press.

Stein, J.K., J.N. Deo, and L.S. Phillips. 2003. Big sites—short times: accumulation rates in archaeological sites. Journal of Archaeological Science 30 (3): 297–316. http://dx.doi.org/10.1006/jasc.2002.0838

Stenzel, H.B. 1964. Oysters: composition of the larval shell. Science 145 (3628): 155–156. http://dx.doi.org/10.1126/science.145.3628.155

Stuiver, M., G.W. Pearson, and T.F. Braziunas. 1986. Radiocarbon calibration of marine samples back to 9000 cal yr bp. Radiocarbon 28 (2B): 980–1021.

Sturtevant, W.C. 1962. Spanish-Indian relations in southeastern North America. Ethnohistory 9 (1): 41–94. http://dx.doi.org/10.2307/480785

Sturtevant, W.C. 1964. Document 42: A Jesuit missionary in South Carolina, 1569–70. In W.E. Washburn (editor), The Indian and the white man: 167–175. New York: Anchor Books.

Surge, D., and K.J. Walker. 2005. Oxygen isotope composition of modern and archaeological otoliths from the estuarine hardhead catfish (Ariopsis felis) and their potential to record low-latitude climate change. Palaeogeography, Palaeoclimatology, Palaeoecology, 228: 179–191. http://dx.doi.org/10.1016/j.palaeo.2005.03.051

Surge, D., and K.J. Walker. 2006. Geochemical variation in microstructural shell layers of the southern quahog (Mercenaria campechiensis): implications for reconstructing seasonality. Palaeogeography, Palaeoclimatology, Palaeoecology 237: 182–190. http://dx.doi.org/10.1016/j.palaeo.2005.11.016

Surge, D., K.C. Lohmann, and D.L. Dettman. 2001. Controls on isotopic chemistry of the American oyster, Crassostrea virginica: implications for growth patterns. Palaeogeography, Palaeoclimatology, Palaeoecology 172 (3–4): 283–296. http://dx.doi.org/10.1016/S0031-0182(01)00303-0

Surge, D., K.C. Lohmann, and G.A. Goodfriend. 2003. Reconstructing estuarine conditions: oyster shells as recorders of environmental change, southwest Florida. Estuarine, Coastal and Shelf Science 57: 737–756. http://dx.doi.org/10.1016/S0272-7714(02)00370-0

Surge, D., G. Kelly, W.S. Arnold, K.J. Walker, and A. Goewert. 2008. Isotope sclerochronology of Mercenaria mercenaria, M. campechiensis, and their natural hybrid form (Bivalvia): does genotype matter? Palaios 23: 559–565. http://dx.doi.org/10.2110/palo.2007.p07-056r

Sutter, F.C., R.S. Waller, and T.D. McIlwain. 1986. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): black drum. U.S. Fish and Wildlife Service. Biological Report 82 (11.51).

Swanton, J.R. 1922. Early history of the Creek Indians and their neighbors. Bureau of American Ethnology Bulletin 73.

Swanton, J.R. 1946. The Indians of the southeastern United States. Bureau of American Ethnology Bulletin 137. Washington, DC: Government Printing Office.

Szabó, K., and I.R. Quitmyer (editors). 2008. World archaeomalacology: the archaeomalacology working group, International Council for Archaeozoology: Papers of the First Inaugural Meeting, Gainesville, Florida, 2005. International Journal of Archaeofauna 17.

Talalay, L.E., D.R. Keller, and P.J. Munson. 1984. Hickory nuts, walnuts, butternuts, and hazelnuts: observations and experiments relevant to their aboriginal exploitation in eastern North America. In P.J. Munson (editor), Experiments and observations on aboriginal wild plant food utilization in eastern North America: 338–359. Prehistoric Research Series VI(2). Indianapolis: Indiana Historical Society.

Thomas, D.H. 1986. Refiguring anthropology: first principles of probability and statistics. Prospect Heights, IL: Waveland Press, Inc. 532 p.

Thomas, D.H. 1987. The archaeology of mission Santa Catalina de Guale: 1. Search and discovery. Anthropological Papers of the American Museum of Natural History 63 (2): 47–161.

Thomas, D.H. 2008. Native American landscapes of St. Catherines Island, Georgia. Anthropological Papers of the American Museum of Natural History 88: 1–1136.

Thomas, D.H., and C.S. Larsen. 1979. The anthropology of St. Catherines Island: 2. The Refuge-Deptford mortuary complex. Anthropological Papers of the American Museum of Natural History 56 (1): 1–179.

Thomas, D.H., and M.C. Sanger (editors and contributors). 2010. Trend, tradition, and turmoil: what happened to the southeastern Archaic? Anthropological Papers of the American Museum of Natural History 93: 1–341.

Thomas, D.H., G.D. Jones, R.S. Durham, and C.S. Larsen. 1978. The anthropology of St. Catherines Island: 1. Natural and cultural history. Anthropological Papers of the American Museum of Natural History 55 (2): 155–248.

Thomas, D.H., M.C. Sanger, and R.H. Hayes. n.d. Revising the 14C reservoir correction for St. Catherines Island, Georgia. Unpublished ms.

Thomas, F.R. 2002. An evaluation of central-place foraging among mollusk gatherers in Western Kiribati, Micronesia: linking behavioral ecology with ethnoarchaeology. World Archaeology 34: 182–208. http://dx.doi.org/10.1080/00438240220134313

Thomas, K.D. 1987. Prehistoric coastal ecologies: a view from outside Franchthi Cave, Greece. Geoarchaeology 2 (3): 231–240. http://dx.doi.org/10.1002/gea.3340020305

Thompson, V.D. 2006. Questioning complexity: the prehistoric hunter-gatherers of Sapelo Island, Georgia. Ph.D. dissertation, Department of Anthropology, University of Kentucky, Lexington.

Thompson, V.D., and C.F.T. Andrus. 2011. Evaluating mobility, monumentality, and feasting at the Sapelo Island Shell Ring Complex. American Antiquity 76 (2): 315–344.

Thorrold, S.R., S.E. Campana, C.M. Jones, and P.K. Swart. 1997. Factors determining δ13C and δ18O fractionation in aragonitic otoliths of marine fish. Geochimica et Cosmochimica Acta 61: 2909–2919. http://dx.doi.org/10.1016/S0016-7037(97)00141-5

Tozzer, A. 1926. Chronological aspects of American archaeology. Proceedings of the Massachusetts Historical Society 59: 283–292.

Ugan, A. 2005. Does size matter? Body size, mass collecting, and their implications for understanding prehistoric foraging behavior. American Antiquity 70: 75–89. http://dx.doi.org/10.2307/40035269

University of Florida Institute of Food and Agricultural Services. 2006. Proceedings from the 1st International Sclerochronology Conference, July 17–21, 2007, St. Petersburg, Florida. Internet resource (http://conference.ifas.ufl.edu/sclerochronology/#overview), accessed on November 17, 2010.

Vander Putten, E., F. Dehairs, E. Keppens, and W. Baeyens. 2000. High resolution distribution of trace elements in the calcite shell layer of modern Mytilus edulis: environmental and biological controls. Geochimica et Cosmochimica Acta 64: 997–1011. http://dx.doi.org/10.1016/S0016-7037(99)00380-4

Van Neer, W., L. Löugas, and A.D. Rijnsdorp. 1999. Reconstructing age distribution, season of capture, and growth rate of fish from archaeological sites based on otoliths and vertebrae. International Journal of Osteoarchaeology 9: 116–130. http://dx.doi.org/10.1002/(SICI)1099-1212(199903/04)9:2<116::AID-OA465>3.0.CO;2-H

Van Neer, W., A. Ervynck, L.J. Bolle, and R.S. Millner. 2004. Seasonality only works in certain parts of the year: the reconstruction of fishing seasons through otolith analysis. International Journal of Osteoarchaeology 14: 457–474. http://dx.doi.org/10.1002/oa.727

Van Sickle, V.R., B.B. Barrett, T.B. Ford, and L.J. Gulick. 1976. Barataria Basin: salinity changes and oyster distribution. Baton Rouge: Louisiana State University.

Versteegh, E.A.A. 2009. Silent witnesses: freshwater bivalves as archives of environmental variability in the Rhine-Meuse delta. Ph.D. dissertation. University of Amsterdam, Netherlands.

Versteegh, E.A.A., S.R. Troelstra, H.B. Vonhof, and D. Kroon. 2009. Oxygen isotope composition of bivalve seasonal growth increments and ambient water in the rivers Rhine and Meuse. Palaios 24: 497–504. http://dx.doi.org/10.2110/palo.2008.p08-071r

Versteegh, E.A.A., H.B. Vonhof, S.R. Troelstra, and D. Kroon. 2010. A molluscan perspective on hydrological cycle dynamics in northwestern Europe. Netherlands Journal of Geosciences 89: 51–60.

Voorhies, B. 2004. Coastal collectors in the Holocene: the Chantuto people of southwest Mexico. Gainesville: University Press of Florida.

Walker, K.J., and D. Surge. 2006. Developing oxygen isotope proxies from archaeological sources for the study of Late Holocene human–climate interactions in coastal southwest Florida. Quaternary International 150: 3–11. http://dx.doi.org/10.1016/j.quaint.2006.01.022

Walker, R.L. 1989. Exploited and unexploited hard clam, Mercenaria mercenaria (L.), populations in coastal Georgia. Contributions in Marine Science 31: 61–75.

Walker, R.L., and C. Cotton. 2001. Oyster bed distribution as a long term environmental indicator for the Duplin River, Sapelo Island, National Estuarine Research Reserve. University of Georgia, School of Marine Programs, Marine Technical Report 01–1.

Walker, R.L., and K.R. Tenore. 1984. The distribution and production of the hard clam, Mercenaria mercenaria, in Wassaw Sound, Georgia. Estuaries 7(1): 19–27. http://dx.doi.org/10.2307/1351953

Walker R.L., A.J. Power, M. Sweeney-Reeves, E. Covington, M. Mitchell, and T. Recicar. 2008. Growth, migration, population structure, and sex ratio of four species of whelks (family Melongenidae) within Wassaw Sound, Georgia. Occasional Papers of the University of Georgia Marine Extension Service 1.

Wallace, R.L. 1975. An archaeological, ethnohistoric, and biochemical investigation of the Guale aborigines of the Georgia coastal strand. Ph.D. dissertation, Department of Anthropology, University of Florida, Gainesville.

Wanamaker, A.D., Jr., H.W. Borns, Jr., D.S. Introne, S. Feindel, and B.J. Barber. 2006. An aquaculture-based method for calibrated bivalve isotope paleothermometry. Geochemistry Geophysics Geosystems 7: Q09011. http://dx.doi.org/10.1029/2005GC001189

Wanamaker, A.D., Jr., K.J. Kreutz, H.W. Borns, Jr., D.S. Introne, S. Feindel, S. Funder, P.D. Rawson, and B.J. Barber. 2007. Experimental determination of salinity, temperature, growth, and metabolic effects on shell isotope chemistry of Mytilus edulis collected from Maine and Greenland. Paleoceanography 22: PA2217. http://dx.doi.org/10.1029/2006PA001352

Ward, G.K., and S.R. Wilson. 1978. Procedures for comparing and combining radiocarbon age determination: a critique. Archaeometry 20: 19–31. http://dx.doi.org/10.1111/j.1475-4754.1978.tb00208.x

Ward, J.W. 1957. The reproduction and early development of the sea catfish, Galeichthys felis, in the Biloxi (Mississippi) Bay. Copeia 4: 295–298. http://dx.doi.org/10.2307/1439158

Waselkov, G.A. 1987. Shellfish gathering and shell midden archaeology. In M.G. Schiffer (editor), Advances in archaeological method and theory 4: 93–210. New York: Academic Press.

Waselkov, G.A., L.C. Steponaitis, E. Mueller, J.M. Herbert, and G.R. Abbe. 1998. Seasonality determinations from archaeological oyster shells: an experimental evaluation of incremental shell growth. Report to the National Science Foundation, award #9421140. Mobile: University of South Alabama.

Webb, S.C., R.E.M. Hedges, and R. Robinson. 1998. The seaweed fly Thoracochaeta zosterae (Hal.) (Diptera: Sphaerocidae) in inland archaeological contexts: δ13C and δ15N solves the puzzle. Journal of Archaeological Science 25: 1253–1257. http://dx.doi.org/10.1006/jasc.1998.0298

Wefer, G., and W.H. Berger. 1991. Isotope paleontology: growth and composition of extant calcareous species. Marine Geology 100 (1–4): 207–248. http://dx.doi.org/10.1016/0025-3227(91)90234-U

Wefer, G., and J.S. Killingley. 1980. Growth histories of strombid snails from Bermuda recorded in their O-18 and C-13 profiles. Marine Biology 60: 129–135. http://dx.doi.org/10.1007/BF00389156

Weide, M.L. 1969. Seasonality of Pismo clam collecting at Ora-82. Archaeology Survey Annual Report 11: 127–141. Los Angeles: University of California.

Wells, H.W. 1959. Notes on Odostomia impressa (Say). Nautilus 72: 140–144.

Wells, J.W. 1963. Coral growth and geochronometry. Nature 197: 948–950. http://dx.doi.org/10.1038/197948a0

White, C.D., M.E.D. Pohl, H.P. Schwarcz, and F.J. Longstaffe. 2001. Isotopic evidence for Maya patterns of deer and dog use at Preclassic Colha. Journal of Archaeological Science 28 (1): 89–107. http://dx.doi.org/10.1006/jasc.1999.0560

White, M.E., and E.A. Wilson. 1996. Predators, pests, and competitors. In V.S. Kennedy, R.I.E. Newell, and A.F. Eble (editors), The eastern oyster Crassostrea virginica: 559–579. College Park: Maryland Sea Grant College.

White, M.E, E.N. Powell, and C.L. Kitting. 1984. The ectoparasitic gastropod Boonea (= Odostomia) impressa: population ecology and the influence of parasitism on oyster growth rates. Marine Ecology 5 (3): 283–299. http://dx.doi.org/10.1111/j.1439-0485.1984.tb00126.x

White, M.E., C.L. Kitting, and E.N. Powell. 1985. Aspects of reproduction, larval development, and morphometrics in the pyramidellid, Boonea impressa (= Odostomia impressa), (Gastropoda: Opisthobranchia). Veliger 28 (1): 37–51.

Whittle, A., and A. Bayliss. 2007. The times of their lives: from chronological precision to kinds of history and change. Cambridge Archaeological Journal 17 (1): 21–28. http://dx.doi.org/10.1017/S0959774307000030

Winterhalder, B. 2001. The behavioural ecology of hunter-gatherers. In C. Panter-Brick, R.H. Layton, and P. Rowley-Conwy (editors), Hunter-gatherers: an interdisciplinary perspective: 12–38. Cambridge: Cambridge University Press.

Winterhalder, B., and D.J. Kennett. 2006. Behavioral ecology and the transition from hunting and gathering to agriculture. In D.J. Kennett and B. Winterhalder (editors), Behavioral ecology and the transition to agriculture, 1–21. Berkeley: University of California Press.

Winterhalder, B., D.J. Kennett, M. Grote, and J. Bartruff. 2010. Ideal free settlement of California’s Northern Channel Islands. Journal of Anthropological Archaeology 29 (4): 469–490. http://dx.doi.org/10.1016/j.jaa.2010.07.001

Withers, K., and M. Hubner. 2009. Bay scallops, Argopecten irradians, in the northwestern Gulf of Mexico (Alabama, Mississippi, Louisiana, and Texas). Marine Fisheries Review 71 (3): 1–5.

Wootton, R.J. 1998. Ecology of teleost fishes. Dordrecht: Kluwer Academic.

Worth, J.E. 1998. Timucuan chiefdoms of Spanish Florida [vol. 1]. Assimilation. Gainesville: University of Florida Press.

Worth, J.E. 1999. Coastal chiefdoms and the question of agriculture: an ethnohistorical overview. Fifty-sixth Annual Southeastern Archaeological Conference, Pensacola, FL.

Worth, J.E. 2004. Guale. In R.D. Fogelson (editor), Handbook of North American Indians [vol. 14]. Southeast: 238–244. Washington, DC: Smithsonian Institution Press.

Worth, J.E. 2007. The struggle for the Georgia coast. Tuscaloosa: University of Alabama Press.

Yen, D.E. 1989. The domestication of environment. In D. Harris and G. Hillman (editors), Foraging and farming: the evolution of plant exploitation: 55–75. Boston: Unwin Hyman.

Yesner, D.R. 1980. Maritime hunter-gatherers: ecology and prehistory. Current Anthropology 21 (6): 727–750. http://dx.doi.org/10.1086/202568

Zubillaga, F. 1946. Monumenta antiquae Floridae (1566–1572). Monumenta historica societatis Iesu 69. Monumenta Missionum Societatis Iesu 3. Roma.

[1] Recent experiments indicate that capuchins have a preference for dietary diversity. When offered choices, they select a variety of items over a greater quantity of their favorite food (Addessi et al., 2010).

[2] Portions of this chapter are based upon work supported by the National Science Foundation under collaborative research grants BCS-1026166, BCS-1026167, and BCS-1026168.