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 1 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

ABSTRACT

Some of the most enduring and fundamental questions in archaeology relate to site seasonality. During which seasons did people occupy coastal archaeological sites? Why is “seasonality” important to our understanding of human behavior? What does this knowledge tell us about life in dynamic estuarine systems? What methods and technologies are available to address key issues of seasonality? Archaeological seasonality is uniquely linked to settlement patterns, resource availability, environmental relationships, anthropogenesis, landscapes, and social complexity.

Archaeologists working in coastal settings typically recover multiple biological proxies that are well suited to explicating questions of human seasonal behavior. The Fifth Caldwell Conference was convened to discuss and report on practiced methods for reading the seasonality record found in common biological proxies. These researchers spoke of how they are applying various methods grounded in the natural sciences to estimate seasonality with particular reference to the archaeology of St. Catherines Island and the Georgia Bight. These methods include stable isotope analysis, 14C dating, longitudinal studies of animals (molluscs and fishes), zooarchaeology, and archaeobotany. The research shows that all plant and animal remains found in a midden contain a record of human behavior.

The authors of these 13 chapters agree that multiple indicators of site seasonality provide the most robust picture of the annual settlement cycle. These papers were initially presented at the Fifth Caldwell Conference, cosponsored by the American Museum of Natural History and the St. Catherines Island Foundation, held on St. Catherines Island, Georgia, May 14–16, 2010.

PARTICIPANTS IN THE FIFTH CALDWELL CONFERENCE

ST. CATHERINES ISLAND, GEORGIA, MAY 14–16, 2010

C. Fred T. Andrus (Associate Professor, Department of Geological Sciences, University

of Alabama)

Sarah G. Bergh (Ph.D. student, Department of Anthropology, University of Georgia)

Elliot Blair (Ph.D. student, Department of Anthropology, University of California, Berkeley)

Rachel Cajigas (Material Culture Analyst, Nels Nelson North American Archaeology Laboratory, American Museum of Natural History)

Nicole R. Cannarozzi (Ph.D. student, Department of Anthropology, University of Florida)

Carol E. Colaninno (Ph.D., Department of Anthropology, University of Georgia)

Christina Friberg (at the time, St. Catherines Island Assistant Archivist, American Museum

of Natural History)

Royce Hayes (Superintendent, St. Catherines Island)

Christa Hayes (St. Catherines Island)

Kandace D. Hollenbach (Ph.D., Archaeological Research Laboratory, Department of Anthropology, University of Tennessee, Knoxville)

Douglas J. Kennett (Professor, Department of Anthropology, the Pennsylvania State University)

Matthew Napolitano (Assistant Laboratory Supervisor, Nels Nelson North American Archaeology Laboratory, American Museum of Natural History)

Alexandra Parsons (Ph.D. student, Florida State University)

Lorann S.A. Pendleton (Director, Nels Nelson North American Archaeology Laboratory, American Museum of Natural History)

Irvy R. Quitmyer (Environmental Archaeology Collection Manager, Florida Museum

of Natural History)

Elizabeth J. Reitz (Professor of Anthropology, Georgia Museum of Natural History,

University of Georgia)

David Hurst Thomas (Curator of Anthropology, American Museum of Natural History)

C. Margaret Scarry (Associate Professor and Director of Undergraduate Studies, Department

of Anthropology, University of North Carolina at Chapel Hill)

Gregory A. Waselkov (Professor, Department of Sociology, Anthropology, and Social Work,

University of South Alabama)

Elizabeth S. Wing (Curator Emeritus, Environmental Archaeology, Florida Museum

of Natural History)

Participants in the Fifth Caldwell Conference, standing in front of the Carriage House Archaeological Laboratory on St. Catherines Island, May 14–16, 2010: (top row, left to right) Fred Andrus, Christina Friberg, Sarah Bergh, Carol Colaninno-Meeks, Lori Pendleton, Margaret Scarry, Betsy Reitz, Matthew Napolitano, Rachel Cajigas, and Elizabeth Wing; (bottom row, left to right) Kandace Hollenbach, Greg Waselkov, Alexandra Parsons, Irvy Quitmyer, Royce Hayes, Christa Hayes, Doug Kennett, David Hurst Thomas, Nicole Cannarozzi, and Elliot Blair.

PREFACE

Elizabeth J. Reitz, Irvy R. Quitmyer, and David Hurst Thomas

Archaeological excavations at coastal sites typically recover multiple biological proxies for seasonal behavior of plant and animal resources and of people. Questions of seasonality are embedded in much of archaeological research, with answers linked to many aspects of cultures and environments, including why seasonality is important to the study of human behavior and what seasonality can tell us about life in dynamic estuarine systems. The Fifth Caldwell Conference was organized to explore aspects of seasonality found in common biological remains and substantive applications with particular reference to the archaeology of St. Catherines Island and the Georgia Bight (USA).

Issues of seasonality and mobility are fundamental to much archaeological research, even when not made explicit. These questions are linked to resource availability, subsistence strategies, economic institutions, and social complexity. But the settlement pattern issue is too often reduced to a dichotomy between mobility on the one hand and sedentism on the other, as though they were mutually exclusive options. As Bar-Yosef and Rocek (1998: 1, italics theirs) argue: “The fact is all societies have a mobility component; the issue is what the form of that mobility is, not whether it exists.” As with most human institutions, residential patterns as well as resource acquisition come in many variations for many different reasons.

Archaeological excavations along the Georgia Bight typically recover thousands of potential “seasonal indicators.” Aten (1981) identifies five characteristics commonly used to study seasonality in animals: presence or absence of skeletal elements (e.g., bones of migratory birds), demography (e.g., changes in the sizes of estuarine fishes as they mature through the annual cycle), morphology (changes in shell contour through the annual cycle, e.g., marsh clams [Rangia cuneata]), structure (changes in shell microstructure correlated with the seasons of the year, e.g., growth phases in hard clams [Mercenaria spp.]), and chemistry (changes in shell composition, e.g., shifting oxygen and carbon isotopes in Mercenaria).

Regardless of approach, these techniques can reveal only when an organism died and some information about environmental conditions prevailing during that individual’s life or at the time of death. Judgments regarding season of availability, procurement, and location (as defined by Monks, 1981) must rest on ecological analogy, which typically requires monitoring modern patterns to correlate hard tissue growth and other aspects of seasonality with annual cycles. The fact that a particular clam died on St. Catherines Island in November/December is, by itself, of limited use in testing theories of seasonality and mobility with regard to the use of resources and locations over time. To articulate season of death with broader inferences requires arguments demonstrating that the death of an organism was contemporaneous with (and relevant to) specific behaviors, cultural institutions, interactions with neighboring groups, site functions, and site histories. Without such linkage arguments, seasonal estimates tell us very little about people.

We believe it is important not to conflate patterns of seasonal site occupation (reflecting mobility strategies), seasonal patterns of resource procurement (reflecting foraging and/or farming strategies), site function, and relationships with people on neighboring islands and the mainland (e.g., Quitmyer et al., 1997: 826). These are very different—if interrelated—facets of human behavior.

The chapters in this volume address specific issues (such as inconsistencies in the ethnohistoric record, refinements in dating archaeological deposits, intersite and intrasite variability, and regional settlement patterns) associated with biological proxies used to assess aspects of seasonality and mobility along the Georgia Bight generally, and on St. Catherines Island in particular. They were originally presented at the Fifth Caldwell Conference, cosponsored by the American Museum of Natural History and the St. Catherines Island Foundation and held on St. Catherines Island, Georgia, May 14–16, 2010.

The first chapter in the volume, by David Hurst Thomas, discusses sampling and inferential problems raised when linking seasonality studies to our understanding of mobility patterns and paleoclimatic change. The author recaps how issues of seasonality and mobility have dominated archaeological research and related discourse on St. Catherines Island, as well as the rest of the Georgia Bight. He specifically reviews efforts to systematically collect archaeological evidence to resolve the conflicting ethnohistoric interpretations of the Georgia coastline (the so-called Guale problem). For the Late Archaic period, inquiry has centered on whether the massive shell ring settlements represent episodic aggregations or long-term, year-round occupations (or both). For the Late Prehistoric period, the “Guale problem” has highlighted contrasting views of residential and logistic mobility for these coastal people.

Douglas J. Kennett and Brendan J. Culleton present a Bayesian chronological framework as a way to determine contemporaneity within and among sites, a procedure essential for assessing seasonal rounds, residential mobility, and determining whether specific sites used during different or the same seasons are coeval. These authors note that seasonality studies depend upon defining culturally meaningful analytical units and analyzing and interpreting seasonality data within the broader context provided by these units. Chronology building is an essential part of defining these analytical units. The authors observe that Bayesian analysis of radiocarbon dates from archaeological sites is routine in Britain, and programs like OxCal provide prepackaged statistical tools with which to develop robust archaeological site chronologies. Custom-built Bayesian statistical environments that analyze and model spatiotemporal patterns in the archaeological record are also being developed, including tools potentially useful for integrating the multiscalar chronological measures necessary for establishing site seasonality and inferring mobility patterns. The authors then provide a new Bayesian chronological framework for interpreting seasonality data on St. Catherines Island, combining stratigraphic information and other prior knowledge with radiocarbon dates to establish more precise and accurate chronological models. This paper concludes that changes in material culture observed at the two Late Archaic shell rings on St. Catherines Island could have occurred within less than a decade. The authors argue that more precise AMS 14C dates could provide additional insights into the cultural processes in play.

The next chapter addresses one of the major kinds of evidence available to archaeologists interested in understanding seasonality along the Georgia coastline—fish. In chapter 3, Elizabeth J. Reitz, Bruce M. Saul, J.W. Moak, Gwendolyn D. Carroll, and Charles W. Lambert compare and contrast seasonal evidence obtained from research on modern and archaeological fishes along the Georgia Coast. Estuarine fishes are a mixture of endemic, marine, and freshwater species attracted to estuaries as nursery grounds and feeding areas. The potential of estuaries to fill these roles varies seasonally, raising the possibility that fishes can serve as proxies for seasonal patterning in human fishing strategies. In this study, the spatial and seasonal habits of modern and archaeological fishes are evaluated for evidence of seasonal fishing strategies. These authors find that fishing was highly selective and that some fish taxa in the archaeological record are not markedly seasonal, limiting the value of simple presence or absence to provide seasonal fishing information.

In chapter 4, Carol E. Colaninno evaluates data from oxygen isotopic profiles and seasonally sensitive vertebrate remains as evidence for year-round occupation at Late Archaic shell rings on the Georgia coast. Specifically, seasonal occupation at five Late Archaic (4200–3100 b.p.) shell rings is explored using oxygen isotopic evidence from hardhead catfish (Ariopsis felis) and Atlantic croaker (Micropogonias undulatus) otoliths. Combined with knowledge of seasonal availability, Colaninno’s results demonstrate that these fishes were captured during multiple seasons at each of the five Late Archaic shell rings; all four seasons are represented at several sites. This suggests that some portion of the human population occupied these sites throughout the year during this period.

Sarah G. Bergh discusses intrasite variability in seasonal occupation at Back Creek Village (a.d. 1200–1600) on St. Catherines Island. These archaeological shell middens likely accumulated outside structures occupied by sedentary households. Bergh evaluates the degree to which intra- and intermidden variation reflects specific modes of shell accumulation. This study uses annual cycles in fishes and hard clam (Mercenaria spp.) growth habits to explore seasonal patterns of midden deposition, which can be linked to site function and mobility. Bergh argues that villagers relied heavily on vertebrate resources present in the estuary throughout the year, suggesting that seasonal mobility to exploit animal resources was not a factor in the settlement system.

In chapter 6, C. Fred T. Andrus presents an integrated, programmatic approach to assessing seasonality and sedentism on the Georgia Bight. Andrus notes that most molluscan sclerochronology research in the southeastern United States focuses on Eastern oyster (Crassostrea virginica) and quahog (or hard clam [Mercenaria spp.]), the two most common taxa in archaeological middens from this area. But he argues that several other molluscs likewise show varying degrees of promise as proxies for season of capture. While these other taxa may not be as abundant as oysters and quahogs, their analysis may provide insight into human behavior in a varied range of ecosystems and offer a more complete picture of subsistence activities. This paper surveys relevant literature and presents new data concerning the development of novel season of capture proxies. Key areas of concern include taxon-specific properties of biomineralization, shell structure, seasonal growth, taphonomy, and geochemistry. The goal is to foster expansion of the current suite of sclerochronological tools available to archaeologists in this region and encourage modern proof-of-concept research.

In chapter 7, Irvy R. Quitmyer and Douglas S. Jones discuss annual incremental shell growth patterns in hard clams (Mercenaria spp.) recovered in archaeological contexts from St. Catherines Island. Hard clams grow by mantle-mediated precipitation of calcium carbonate forming a predictable alternating pattern of opaque (white) and translucent (gray) shell increments corresponding to seasonal changes in water temperature. This research applies sclerochronological techniques to document the annual periodicity of shell formation in modern populations of hard clams from St. Catherines Island and applies this model to the interpretation of Archaic-period archaeological assemblages. Their results demonstrate that hard clams recovered from the St. Catherines and the McQueen shell rings were intensively harvested during the late winter and spring seasons. These authors explicitly address two companion issues associated with high levels of sedentism: the extent to which natural and anthropogenic processes impact these resources, and whether there is evidence of resource management strategies. They clearly demonstrate that knowing something about cultural activity is to know something about the biology and ecology of the animals that were used.

Douglas S. Jones, Irvy R. Quitmyer, and Chester B. DePratter present oxygen isotope validation of annual macroscopic shell growth increments in modern and zooarchaeological hard clams (Mercenaria spp.) from the Litchfield Beach Estuary, South Carolina. They note that the periodicity of incremental shell growth in Mercenaria spp. is a powerful tool for estimating the season of resource procurement and anthropogenic impact on zooarchaeological resources. The seasonal pattern of shell formation in modern populations is well documented throughout their range, but recent research suggests that changes in the marine environment can quickly and significantly alter patterns of growth within a region. The research analyzes the variability of oxygen isotope ratios (18O/16O) in shell carbonate to validate the seasonal periodicity of incremental shell growth in modern and zooarchaeological specimens recovered from Litchfield Beach. The data verify the hypothesis that the periodicity of incremental shell growth has not changed over the past 2000 years, allowing the population dynamics of modern and ancient populations in the region to be assessed. The authors document significant changes in the composition of the ontogenetic age classes of pre-Hispanic hard clam populations’ top down impact on hard clam beds.

In chapter 9, Deborah Ann Keene reevaluates the use of impressed odostomes (Boonea impressa) as proxies for season of capture for eastern oysters (Crassostrea virginica) recovered from middens along the Georgia Bight. The potential for zooarchaeological research was first explored by Russo (1991) who hypothesized that determining the season of death for Boonea impressa would reveal the season of death for the oysters to which they were attached. By assuming that most Boonea impressa are born at the same time of year, live for about one year, and grow steadily throughout that year, Russo argued that their season of death, as well as season of collection for oysters, could be estimated from odostome size. To test his hypothesis, he collected and measured modern samples of Boonea impressa from the northeast coast of Florida for 14 months, then developed a model of their yearly growth based on shell length. Keene notes that whereas additional data have been collected on the growth, reproduction, and behavior of Boonea impressa in North Carolina, we still do not understand how reproduction and growth are affected by environmental factors, meaning that studies using Boonea impressa to determine season of capture require deeper inquiry to establish a more reliable model to assess the season of oyster harvest. Keene proposes several potential ways to evaluate accuracy, and concludes that the cost effectiveness and ease of this method for determining season of death means that it should not yet be abandoned.

Nicole R. Cannarozzi evaluates the potential of the Eastern oyster (Crassostrea virginica) as a proxy for seasonality using zooarchaeological collections from St. Catherines Island. She discusses how determining the season of collection of oysters in the Georgia Bight is complicated by the dynamic nature of the estuaries these molluscs inhabit. Environmental changes may cause unpredictable biological responses, including the formation of multiple shell growth breaks. Currently, stable isotope geochemistry is the most effective method for determining seasonality of oyster harvest in the area. Morphological data show that different habitats were exploited and/or oyster habitats on St. Catherines have changed considerably over time. She includes in her study measurements of impressed odostomes (Boonea impressa), which indicate year-round collection with the greatest number of individuals collected during cool months.

In chapter 11, C. Margaret Scarry and Kandace D. Hollenbach examine the question of whether plant data derived from archaeological samples provide reliable evidence of seasonality in the past. In most environments, plants have predictable cycles of flowering and fruiting, for example, and seem likely candidates for estimating the season(s) of occupation. The potential to delay harvest and to store many plants, however, complicates direct associations between harvest seasons and seasonal residential patterns. The authors, instead, consider seasonal subsistence rounds from the perspective of operational chains involved in acquiring, processing, and consuming key plant resources. To do this, they draw upon species inventories from archaeological sites throughout the region as well as ethnographic and ethnohistoric information. They conclude that their hypothetical round of plant handling could be conducted from marshside settlements on St. Catherines Island without requiring seasonal settlement relocation.

Gregory A. Waselkov discusses more general implications of seasonality and mobility in coastal research. He notes that coastal archaeologists have refined their studies of subsistence remains for evidence of resource intensification and seasons of resource use and residential patterns. Seasonality, in particular, is far more complex than earlier models suggested. But Waselkov warns that current archaeological methods employed to document and interpret subsistence seasonality (which is our principal portal to the multiple facets of residential mobility and sedentism) have many shortcomings. Although even our best available methods have real limitations on seasonal resolution, Waselkov suggests that a higher standard of analysis can provide a firmer basis for models of coastal sedentism and mobility.

In the concluding paper, Elizabeth S. Wing discusses the papers presented at the Fifth Caldwell Conference, noting that many challenges exist in documenting the seasonal foraging patterns of the past. She emphasizes the expansion of archaeological techniques available for examining seasonal change over the past few years and encourages further integration of data from such diverse sources as charcoal, tree rings, growth increments in mollusc shells and fish otoliths, and fish faunal assemblages. Wing states that these techniques provide a more complete understanding of human conditions in the past. She also underscores the difficulty of integrating data from plants with those from animals due to the relatively poorer preservation of plant remains, and suggests that the recovery of additional plant remains from waterlogged conditions could help meld these two datasets. Wing notes that the bioarchaeological remains discussed in these papers derive from excavated archaeological deposits and points to the importance of documentary evidence in providing (sometimes conflicting) firsthand glances at the past foraging activities of people living along the Georgia Bight.

ACKNOWLEDGMENTS

We express our thanks to the trustees of the St. Catherines Island and Edward John Noble foundations for their long-term support of the Caldwell Conference series, cosponsored by the American Museum of Natural History and held on St. Catherines Island, Georgia. We are especially grateful to Ms. June Gibson, for her friendship, guidance, and willingness to stick with us over the decades. We are also grateful to Mr. Jeremy Smith (President, St. Catherines Island Foundation), Mr. Noble Smith (Executive Director, St. Catherines Island Foundation), Mr. David Smith (Director, St. Catherines Island Foundation), and the late Mr. Bradford Smith (Co-Chair, St. Catherines Island Foundation); each has made unique contributions to our archaeology program.

Special thanks go to Mr. Royce H. Hayes (Superintendent of St. Catherines Island) who has facilitated the Caldwell Conference series in countless ways. We are likewise grateful to the members of the St. Catherines Island staff, past and present, who helped out in the hundreds of ways that made our archaeological investigations more productive (and more fun). We are also extremely grateful to the staff of the St. Catherines Island Archaeological Project: Mr. Elliot Blair, Ms. Rachel Cajigas, Ms. Christina Friberg, Ms. Chelsea Graham, Mr. Matthew Napolitano, Ms. Lori Pendleton, Ms. Ginessa Mahar, Ms. Diana Rosenthal, Mr. Matthew Sanger, and Ms. Anna Semon; each made numerous behind-the-scenes contributions that made the Fifth Caldwell Conference and subsequent publication operate so smoothly.

We thank Dr. Kenneth Ames, Dr. Geoff Bailey, Dr. Robert Cerrato, and Dr. Jon Erlandson for their thoughtful and critical reviews of the entire draft manuscript.

Mr. Irvy Quitmyer took the photo that is featured on the cover. We also thank Mr. Elliot Blair, Ms. Rachel Cajigas, Ms. Christina Friberg, Ms. Chelsea Graham, Ms. Ginessa Mahar, Mr. Matthew Napolitano, Ms. Lorann S.A. Pendleton, Ms. Diana Rosenthal, Mr. Matthew Sanger, and Ms. Anna Semon for assistance with the manuscript production. We acknowledge the contributions of Ms. Brenda Jones and Dr. Mary Knight for their editorial efforts and Ms. Jennifer Steffey for her skill and patience in designing the cover and assisting with the final artwork.

CHAPTER 1: SEASONALITY AND MOBILITY ON THE GEORGIA BIGHT: WHY SHOULD WE CARE?

David Hurst Thomas[1]

Three years ago, our team published a three-volume, 1136-page monograph called Native American Landscapes of St. Catherines Island (Thomas, 2008), presenting the data and synthesizing all of our previous research on St. Catherines Island (except for the archaeology of Mission Santa Catalina de Guale). The American Museum of Natural History’s program in archaeology on St. Catherines Island has always been about teamwork, and the Native American Landscapes volumes clearly reflects this broad-based, interdisciplinary bias, with more than two dozen contributors to the final publication.

Four decades of archaeological research, encapsulated in Native American Landscapes, addressed aboriginal lifeways of indigenous St. Catherines Islanders in terms of four deceptively simple questions (after Thomas, 2008: iii):

How and why did the human landscape (reflected in settlement patterns and land use) change through time?

To what extent were subsistence and settlement patterns shaped by human population increase, intensification, and competition for resources?

What factors can account for the emergence of social inequality in Georgia’s Sea Islands?

Can systematically collected archaeological evidence resolve the conflicting ethnohistoric interpretations of the aboriginal Georgia coastline (the so-called Guale problem).

In this chapter, I focus on the fourth of these research objectives.

A critical element in the scientific enterprise, I believe, is the right to be wrong. Given the objectives guiding the Fifth Caldwell Conference, it seems worthwhile to explore the pivotal relationship between seasonality of site occupation and human mobility strategies. To understand how seasonality inferences were embedded within the St. Catherines Island archaeological program, I’ll first summarize the previous findings, then deconstruct the Native American Landscapes volumes specifically with respect to seasonality (Thomas, 2008). The idea is to highlight some shortcomings in our previous work and anticipate some ways to improve our understanding of site seasonality and its impact on the estuarine systems of the Georgia Bight.

WHAT’S THE ‘GUALE PROBLEM’?

The Guale Indians of the interior Georgia Bight were among the first indigenous peoples met by Europeans exploring north of Mexico. After brief contact with the Spanish in 1526, this Muskhogean-speaking group later encountered the French in 1562–1563. Then, beginning in 1566, the Guale experienced a sustained period of Spanish colonization and missionization.[2] By 1684, the gradual southern withdrawal of the Spanish coupled with the southward expansion of the Carolina colony fostered relocation and reorganization of the vastly reduced Guale population.[3]

Conflicting Views

Building on Swanton’s (1922) landmark synthesis The Creek Indians and Their Neighbors, Lewis Larson (1969, 1980) contrasted the Guale with apparently more sedentary peoples of Apalachee Florida. Concluding that coastal Georgia environments seriously constrained and hampered aboriginal lifeways, Larson argued that only a highly dispersed, seasonally mobile population could have survived there.

Particularly critical to this interpretation were ethnohistoric documents from the central Georgia Bight during the 1560s (Larson, 1969: 293–297), especially the accounts by Fr. Jean Rogel at Orista (Sturtevant, 1964: 170), Fr. Antonio Sedeño (who described coastal Georgia as “the most miserable thing ever discovered” (Zubillaga, 1946: 424), and René Laudonière (Bennett, 1975: 121), who recorded similar impressions in 1564 at Outina (a Timucuan settlement located just west of the St. Johns River in northeastern Florida (see Worth, 1998: 21 and Thomas, 2008: chap. 11). These (and other) documents convinced Larson (1980: 209, 218) that the infertile and patchy soils of coastal Georgia were “the primary reason for the scattered and small size of the agricultural production unit.” He concluded that along the Guale coast “permanent settlements were not the rule, for long seasonal junkets in pursuit of game mitigated against a settled populace” (Larson, 1978: 122; see also 1969: 293–297, 1980: 206–209). Despite some modifications in the mid-1980s (addressed in Thomas, 2008: chap. 11), Larson’s perspectives on Guale subsistence and settlement were accepted and amplified by a number of investigators (esp. Crook, 1984, 1986; see also Wallace, 1975: 265–271; Pearson, 1977: 62–63; Reitz and Scarry, 1985: 46; Reitz, 1988, 1991; see also Thomas, 2008: chaps. 11 and 35).

Likewise, arguing long-term, high residential mobility, Crook (1986: 17–20, fig. 2, 2004; see also Crook, 1984: 260, 1986: 18–20; Larson, 1980) proposed a “purely aboriginal” fission-fusion settlement model for the precontact Guale people. Crook defined the Guale wintertime settlement (mid-December through mid-March) as “minimal settlements” consisting of a single matrilineage, dispersed “adjacent to tidal streams which permitted access to the estuarine system” (1986: 22).[4] Crook (1986: 53) summarized his “Annual Model” this way: “large villages primarily occupied during the summer, smaller settlements occupied either multi-seasonally or during the fall–winter season, and small sites occupied for very short periods of time do exist” (see also Thomas, 2008: table 11.6).

Ethnohistorian Grant Jones (1978, 1980) came to a quite different conclusion after his own close reading of the same documentary sources: “On the empirical level I believe that [the conventional wisdom] has led to an overstatement of the isolation of the Guale from the interior, the unproductivity of Guale horticulture, and the scattered quality of Guale settlements” (Jones, 1978: 189). Jones (1978: 179, 191, 194) believed that the Jesuit reports deliberately exaggerated the “misery” of the land, and proposed instead that the Guale lived in “dispersed towns … there is no doubt that there was a town center with a large round community building, a chunky field, and some residential structures. The regular presence of some form of mortuary structure is likely. The town center was surrounded by dispersed households practicing shifting horticulture. Intergroup and intragroup economic exchanges and redistribution systems, in a context of considerable resource variability contributed toward a dependable food supply that probably required little regular seasonal residential mobility” (Jones, 1978: 200).[5]

Jones (1978: 209) summarized his position this way: “Larson’s … reliance on the Jesuit view of the sixteenth century Guale … led him to consider the Guale as an isolated, distinctive adaptation. While it is significant that the Guale were adapted to special environmental conditions, I have argued that these conditions neither created isolation nor impeded the development of a complex level of sociocultural integration.… Despite their environmental and adaptive differences, the Guale and the interior groups shared such basic features as chiefdoms, military federations, matrilineality, and dual aspects of organization. … [I]t is of considerable theoretical importance that such an exploration eventually be attempted, for the Guale case seems to demonstrate that more than one set of adaptive conditions may well combine to create highly similar features.”

These are vastly different interpretations of the ethnohistoric record for the Georgia coastline, and the so-called Guale problem became the central research question addressed in the Native American Landscapes volumes (Thomas, 2008; see also 1987: 57–64, Worth, 1999; Saunders, 2000b; Ruhl, 2003: 188–189; Keene, 2004: 672).

Competing Hypotheses and Logical Consequences

The Guale problem turns on the twin issues of residential mobility and economic intensification, which I believe can be succinctly expressed in two competing hypotheses extracted from the ethnohistoric record:

The Jesuit hypothesis: Guale Indians were egalitarian, highly nomadic, mostly nonfarming foragers who lived in low-density, small, seasonal aggregations;

The Franciscan hypothesis: Guale Indians were a hierarchical, ranked society; they relied heavily on maize cultivation, rarely moved their residences, and lived in high-density “dispersed towns.”

Native American Landscapes of St. Catherines Island (Thomas, 2008) was all about testing these two hypotheses.

The truth, of course, is that scientists don’t really test their hypotheses—what we test are the logical implications of our hypotheses. Essentially, hypotheses are abstract, inductive statements that must be translated (through deductive reasoning) into logical, empirical, material consequences. Such deductive arguments generally take the form of “if ... then” statements: If the hypothesis is true, then we will expect to observe the following outcomes. Bridging the gap from if to then is the tricky step.

With respect to the Guale problem, we framed the following logical consequences from the two competing hypotheses:

The Jesuit hypothesis: If the Jesuit observations correctly reflect mid-17th century Guale settlement patterns, then the resulting archaeological record should reflect a palimpsest of some four-season settlements and several seasonally specific settlements. The most concentrated occupations should occur during the summer, with a dispersed series of archaeological accumulations during the early fall, followed by moderate occupational intensity from the late fall through winter. From the fall through springtime, the Guale were residentially mobile foragers who should have produced an archaeological record of (1) dispersed oak forest settlements (fall and springtime occupations only) and (2) dispersed marshside settlements (late fall–winter and springtime occupations only).

The Franciscan hypothesis: If the Franciscan observations correctly reflect mid-17th century Guale settlement patterns, then the resulting archaeological record should reflect a basic strategy of low residential mobility centered on “dispersed towns,” generally positioned along the maritime forest/marsh margin. Whereas some Guale may have shifted their winter residence to be closer to hunting, fishing, or shellfish patches, most St. Catherines islanders maintained four-season residence in a single community. Hunting, fishing, and wood-collecting trips took individuals away from the community on a temporary basis. Guale dispersed towns were located mostly along the margins between maritime forest and saltwater marshes. These forager farmers (or, perhaps, farmer foragers), lived in large, relatively stable residential central places, out of which logistical forays of small “task groups” brought plants and animals back home. This strategy of minimal residential mobility should produce a distinctive archaeological record, characterized by sustained, four-season occupations of marshside settlements, with only minimal evidence of single- or biseasonal occupations elsewhere.

ARCHAEOLOGY AND THE GUALE PROBLEM

The American Museum of Natural History harnessed a broad array of field and analytical techniques to test the Jesuit and Franciscan hypotheses (esp. Thomas, 2008: chaps. 7–12). We situated this fieldwork within the general paradigm of human behavioral ecology, grounded in three basic models (Thomas, 2008: chaps. 7–10). The diet-breadth (or prey choice) model addressed the issue of which foods an efficient forager should harvest from all those available on St. Catherines Island. Diet-breadth models predict that foragers will optimize the time spent capturing prey, and employ the simplifying assumptions that all resources are randomly distributed (without patches) and that “capture/handling” and “search” times represent the sum total of all time spent foraging. We also applied the patch choice model, which, combined with the central limit theorem, predicts that foraging efforts will correlate directly with efficiency rank order, meaning that foragers should spend more time working the higher-ranked patches and less time in patches with lower energetic potential. Using the central place foraging model, we investigated the time/energy spent processing resources at temporary camps before transport to a residential base. For several years, we have also conducted a series of optimal foraging experiments, specifically addressing procurement and return rates for key marine and terrestrial resources that would have been available to aboriginal foragers on St. Catherines Island.

We conducted a 20% probabilistic transect survey of St. Catherines Island, walking and probing for buried sites across a series of 31 east–west transects, each 100 m wide (fig. 1.1). This procedure generated a sample of 122 archaeological sites, which we tested with more than 400 1 m × 1 m units. Because the transect sampling was heavily biased toward sites with marine shell, we also conducted a systematic shovel testing program and augmented these systematic surveys with a direct shoreline reconnaissance (mostly following the late Holocene surfaces), recording an additional 84 shoreline sites. By plotting the distribution of these known-age sites across the Holocene beach ridges, we developed a detailed sequence documenting the progradation and erosion of beach ridge complexes adjacent to tidal estuaries and coastal shorelines on St. Catherines Island.

These data in hand, we turned next to the analytical tools necessary to make sense of this archaeological record, beginning with chronological controls.

Fig. 1.1. The randomized transect research design employed in the island-wide survey of St. Catherines Island (after Thomas, 1987: fig. 22).

DEVELOPING MULTISCALAR CHRONOLOGIES

Chronology is at the root of the matter, being the nerve electrifying the dead body of history.

–Berthold Laufer (1913: 577)

A century ago, addressing the annual meeting of the American Anthropological Association, ethnographer Berthold Laufer pretty much got it right—chronology really does lie at the heart of the matter. Archaeologist Alfred Tozzer (1926: 283) subsequently expressed similar sentiments about archaeological data having “an inert quality, a certain spinelessness when unaccompanied by a more or less definite chronological background” (see also O’Brien and Lyman, 1999: chap. 1).

Laufer (1913: 576) went on to suggest that whereas archaeology and ethnology are “inseparably one and the same—emanations of the same spirit, pursuing, as they do, the same ideal, and working to the same end,” they operate at different timeframes. “When archaeology and ethnology have drawn up each its own chronology, then the two systems may be pieced together and collated, and the result cannot fail to appear.” This observation is important because Laufer explicitly recognized that chronology typically operates at multiple levels—what today we might call a “multiscalar” approach to chronology control.

Today, we understand that archaeology’s initial objective must always be chronological—reflecting the necessity of establishing a firm grasp on time before attempting to reconstruct ancient lifeways or addressing more processual matters. In our St. Catherines Island research, we have approached chronology in the multiscalar fashion anticipated by Berthold Laufer a century ago:

The Hour Hand: The St. Catherines Island ceramic sequence provided the “little hand” on the clock, generally providing temporal controls at a submillennial level of resolution.

The Minute Hand: The radiocarbon sequence became the “big hand” on the clock, generating temporal controls at a century level of resolution.

The Second Hand: Site seasonality studies offer microchronological controls at the resolution of months or even weeks.

Below, we discuss how this multiscalar approach to chronology allowed us to evaluate the Guale problem on St. Catherines Island, especially as it relates to site seasonality studies.

The St. Catherines Island Ceramic Chronology: Reading the Hour Hand

The regionalized random sampling of St. Catherines Island generated more than 15,000 potsherds from 122 archaeological sites (Thomas, 2008: tables 20.3 and 20.5). Perceived as “index fossils,” these diverse ceramic assemblages provided the initial (and most coarse-grained) chronological controls.

All of the aboriginal ceramics recovered from St. Catherines Island were initially classified according to the northern Georgia coast ceramic chronology, as refined by Chester DePratter (1979: table 30; as updated in DePratter, 1991: table 1; see also Thomas, 2008: chap. 14 and 15). In this synthesis, DePratter relied on temper, surface decoration, rim form, and vessel form that demonstrably vary “asynchronously” (DePratter, 1979: 122). DePratter’s chronological sequence contained seven major cultural periods, subdivided into nearly two dozen archaeological phases (table 1.1.) This coarse-grained approach to chronology provided temporal estimates accurate at the submillennial level.[6]

TABLE 1.1: Comparison of Northern Georgia Coast and St. Catherines Island Chronologies. (Northern Georgia coast after DePratter, 1979: table 30, as modified by DePratter, 1991: table 1. St. Catherines Island after Thomas, 2008: table 15.3.)

Phases

Northern Georgia coast chronology age (uncalibrated)

Northern Georgia coast chronology age (calibrated)

St. Catherines Island chronology age (calibrated)

a.d. 17001

—

a.d.17002

Altamaha

a.d. 1580

—

a.d. 15802

Irene

a.d. 1325

a.d. 1310–1390

a.d. 1300

Savannah

Savannah phase deleted

a.d. 1200

a.d. 1280

a.d. 1300

St. Catherines

a.d. 1000

a.d. 1050–1150

a.d. 800

Wilmington

a.d. 500

a.d. 630

a.d. 350

Deptford

400 b.c.

400 b.c.

350 b.c.

Refuge

1100 b.c.

1360 b.c.

1000 b.c.

St. Simons

2200 b.c.

2750–2860 b.c.

3000 b.c.

Radiocarbon Dating:Reading the Minute Hand

Monitoring radioactive emission from organic specimens by determining the current rate of 14C breakdown, the radiocarbon method estimates the length of elapsed time since the death of a plant or animal. Within the last couple of decades, physicists have discovered that the atmospheric level of radiocarbon has changed somewhat over the last several millennia, enabling archaeologists to “correct” their radiocarbon dates using an absolute chronology based on radiocarbon dating of known-age bristlecone pine samples. New advances in accelerator-based radiocarbon methods permit archaeologists to use extremely small samples, vastly stretching the potential of the method.[7]

By itself, the radiocarbon method tells us nothing about human activities in the past. A 14C date merely estimates when a certain hickory nut dropped to the ground or a specific hard clam died. In each case, the event being dated must be demonstrated to be coeval with a behavioral (cultural) event of interest.

Throughout the St. Catherines Island research, we have emphasized the importance of radiocarbon dating in both archaeological and geological perspectives. The St. Catherines Island archaeological research is currently grounded in a database of roughly 300 14C determinations, most of them processed on “cultural” samples recovered from documented archaeological contexts on St. Catherines Island,[8] primarily burial mounds and shell middens. We have an additional suite of 14C dates from noncultural contexts, primarily organics and marine shell samples collected in conjunction with vibracore sampling and surface geological reconnaissance (see Bishop et al., 2011: appendix 1 for a compilation of these dates). Each radiocarbon date was calibrated according to the conventions and protocols discussed in Thomas (2008: chap. 13).

Radiocarbon dating provides temporal estimates generally accurate at the level of centuries, sometimes even at the decades level.

Site Seasonality: Reading the Second Hand

So far, we have emphasized the importance of grounding St. Catherines Island archaeology within a solid macrochronological framework—an ordering of events within segments of millennia, centuries, and even decades. But addressing the Guale problem requires more fine-grained temporal controls—certainly on the order of seasons, perhaps even months or weeks. Literally thousands of potential “seasonal indicators” were recovered during our excavations on St. Catherines Island and (following Aten, 1981) we explored several commonly employed methods for determining seasonality in such sites: presence or absence of skeletal elements (such as bones from migratory species), demography (changing size of estuarine fishes as they mature through the annual cycle), morphological changes in shell contour during the annual cycle, microstructural changes correlated with the seasons of the year, and chemical changes in shell composition (such as shifting oxygen and carbon isotopes).

The Incremental Growth Sequence in Mercenaria: As we developed the archaeological research design for St. Catherines Island, we recognized the potential for determining the seasonality of harvest by analyzing growth increments in the shell of hard clams (Mercenaria mercenaria), which occur in some abundance in the local shell middens (O’Brien and Thomas, 2008). Such studies were in their infancy in the mid-1970s, with only a limited literature then available (esp. Clark, 1968, 1974; Weide, 1969; Coutts, 1970, 1975; Coutts and Higham, 1971; Ham and Irvine, 1975; Kennish and Olsson, 1975; Koike, 1975).

Most of these pioneering studies emphasized the importance of modern controls for understanding the variability introduced by changing water temperatures and salinity, tides, predation, spawning, and other environmental factors. On St. Catherines Island, we began collecting a modern control sample of Mercenaria mercenaria in 1975, a process that continued, somewhat sporadically, over a nine-year interval; an independent sample of modern Mercenaria was also collected between April 1994 and March 1995, in support of the oxygen isotope study (Andrus and Crowe, 2008).

Working with George R. Clark II (1979), we began a program of seasonal analysis by analyzing Mercenaria recovered from Johns Mound, Marys Mound, and McLeod Mound (see also Thomas and Larsen, 1979; Larsen and Thomas, 1982: 338). Clark concluded that most hard clams interred in these mortuary sites had been harvested during the winter months, probably December and January. But because these zooarchaeological samples were recovered from a secondary, nonmidden context, the complex formation processes involved precluded actual seasonal dating of the mortuary activities. Still, we were encouraged that seasonal patterns were indeed evident in the ancient Mercenaria samples recovered archaeologically, and we moved on to consider hard clam seasonality in the various occupational sites of St. Catherines Island.

Initial laboratory observations of growth increments along the ventral margins, compiled mostly between the late 1970s and mid-1980s, were expressed in Clark’s descriptive terminology (e.g., “early gray,” “early-mid white,” “probably end of white,” and so forth). Since that time, considerable progress has been made on the seasonal analysis of molluscs. O’Brien and Thomas (2008) made use of the then-standardized, six-part subdivision of annual shell growth (Jones, 1980; Quitmyer et al., 1985, 1997: 830), but converted to a four-stage scale, which was then (fig. 1.2) correlated with approximate season of harvest:

O1–2 (initial to intermediate opaque increment): Winter (mid-December–mid-March)

O3 (terminal opaque increment): Early spring (mid-March–mid-April)

T1 (initial translucent increment): Spring (mid-April–mid-June)

T2–3 (intermediate to terminal translucent increment): Summer and fall (mid-June–mid-December)

Figure 1.2 summarizes the modern control sample, pooled from both St. Catherines Island collection sites (after O’Brien and Thomas, 2008: fig. 17.4).

Mercenaria suitable for seasonal analysis were recovered from nearly 85% (110 of 130) of the sites sampled in the island-wide survey, and we saved every single undamaged clam ventral margin for potential seasonal analysis. O’Brien and Thomas (2008: 484–486) elaborate the various ways in which these valves were processed for analysis, including blind testing and additional quality controls employed.

Because such analysis was time-consuming and labor intensive, we instituted a sampling scheme to narrow down the number of clams to be analyzed, while still avoiding the introduction of bias in the winnowing process. After the ceramics from the survey sites were analyzed (using the St. Catherines Island ceramic chronology, discussed above)—and we could classify most sites according to archaeological period(s)—we applied a series of sampling conventions to select appropriate Mercenaria for seasonal analysis:

Single-component sites: If fewer than 25 readable clams were available, all clams were analyzed. If more than 25 suitable clams were recovered, the available valves (or fragments) were numbered sequentially, and a sample of 25 was selected using a table of random numbers. Some “single component” sites also contained evidence of secondary occupations during other ceramic periods. When this happened, Mercenaria samples were taken whenever possible from “temporally discrete” test pits and/or excavation levels (from those units and levels containing only one ceramic complex) by randomly selecting from within these relatively homogeneous intrasite areas.

Double-component sites: Each component was sampled independently by targeting relatively homogeneous test pits (and/or specific levels) from each major temporal component. We then selected up to 25 clams from each component (randomly sampling in the case of n > 25).

Multiple-component sites: We wanted to analyze 25 valves from each of the identified components, but in practice, we never recovered sufficient Mercenaria to do this. As a result, we analyzed whatever clams were recovered and attempted to determine the archaeological age of each specimen by charting associated potsherds.

Undated components: Several sites contained sufficient Mercenaria for seasonal analysis, but too few potsherds to assign a probable period of occupation. The seasonal estimates were included in the overall, island-wide total, but not in the period-by-period tallies.

Although this sampling procedure is, admittedly, a bit mechanistic, we were seeking a way to generate a relatively uniform, representative sample of hard-shelled clams selected for analysis by reducing the overall number of analyzed specimens to approximately 2000 individual Mercenaria valves (or fragments). Of these, 1771 individual specimens (or fragments) provided usable growth increment estimates, enabling us to address seasonal patterns during the 5000 years of human history (O’Brien and Thomas, 2008).[9]

Russo (1991) has also published estimates of seasonality in oyster collection on St. Catherines Island by employing measurements of impressed odostome (Boonea impressa) recovered from Meeting House Field. His analysis of Boonea determined that oyster collection took place primarily during the fall, with summer as a secondary collection period (Russo, 1991: 219). Russo’s correlative study of seasonality in Mercenaria at Meeting House Field (Russo and Saunders, 2008) employed the Kings Bay, Georgia control sample (Quitmyer, Hale, and Jones, 1985) to analyze the zooarchaeological specimens from Meeting House Field. Overall, these data suggest a year-round site occupation, though the evidence for summer occupation is limited. Of particular interest was the difference in oyster collection and quahog collection in the fall, although both species were collected in varying amounts throughout the year.

Assessing Season of Capture in Nonhuman Vertebrate Remains: The island-wide transect survey produced an extensive and diverse set of vertebrate faunal remains collected systematically from archaeological sites tested across the entire island. Elizabeth Reitz and her colleagues analyzed this vertebrate faunal assemblage, which contains at least 586 individuals represented by 14,970 vertebrate specimens (Reitz, 2008; Reitz and Dukes, 2008). Reitz (2008: 623–624, 660–663, table 22.72) has discussed the presence of numerous seasonal indicators in the vertebrate zooarchaeological samples recovered from archaeological sites on St. Catherines Island—especially (1) unshed deer antlers, (2) juvenile deer dentition, (3) presence of shark remains, and (4) presence of sea catfish remains.

Fig. 1.2. Interpolated estimates of incremental growth stages for the modern control sample of Mercenaria collected from St. Catherines Island.

Seasonality and the Guale Problem

With this multiscalar, three-tiered approach to chronology, we synthesized the evidence from the island-wide archaeological survey, documenting residential mobility and human population increase between 3000 cal b.c. and cal a.d. 1300 (Thomas, 2008: chaps. 32–34). Overall, these data demonstrate (1) an exponential increase in human population through time, and (2) a low degree of residential mobility throughout the entire aboriginal period. This pattern continued through the late prehistoric (Irene) period, characterized by the largest and most frequent archaeological occupations recorded in the island-wide survey. Irene occupations accumulated at an extremely rapid rate (34 occupations/century) and the number of recorded archaeological components skyrocketed to 52 (for an average of 17.33 components/century; Thomas, 2008: table 30.1). This is, by far, the densest concentration of archaeological remains recorded for any aboriginal period on St. Catherines Island. The Irene period also had the largest proportion of “large” sites and the smallest proportion of “small” sites (see definitions in Thomas, 2008: table 30.2) recorded during the probabilistic survey.

We generated seasonality estimates for 42 Irene-period components (representing 124 seasonally specific occupations; see fig. 1.2). More than 40% of these Irene components had all four seasons represented and another 36% were occupied in (at least) three seasons. Conversely, only four Irene components represented a single season (each of these being a winter-only occupation). Throughout this discussion, we cautioned against equating a four-season archaeological occupation with “sedentism” (in the conventional ethnographic and ethnohistoric usage).[10]

With respect to the implications derived from human behavioral ecology, the upshot was simple and conclusive: Optimal foraging considerations strongly militate in favor of logistical, rather than residential, mobility. Even factoring in the shifting shape of St. Catherines Island over the past five millennia, it is clear that all habitats on the island could have been systematically searched and exploited by individual foragers who could easily return home daily. These biogeographic constraints suggest that St. Catherines Island foragers could have pursued a strategy of logistic procurement and low residential mobility (at least during times of relatively favorable climatic conditions).

The vast preponderance of archaeological evidence supports a collector strategy of low residential mobility. For most of the time, Irene populations apparently did live, year round in dispersed towns located along the forest-marsh margin (per Jones, 1978: 193–194). Expressed in terms of expectations from central place foraging theory, more than 80% of the archaeological components encountered on St. Catherines Island (for all temporal periods) fit the model of sustained and multiseasonal marshside settlements. Only limited evidence exists for (1) single- or biseasonal occupations or (2) inland, special-purpose, short-term settlements.

To conclude, the combined evidence from the island-wide archaeological survey, coupled with recent ethnohistoric interpretations and modeling from human behavioral ecology would seem to resolve the Guale problem, overwhelmingly rejecting the Jesuit hypothesis, at least on St. Catherines Island. The Franciscan hypothesis, on the other hand, is entirely consistent with the newly available evidence, confirming and amplifying ethnohistorian Grant Jones’s (1978, 1980) perception of the contact-period Guale people: These were largely sedentary foraging farmers who lived in optimally positioned marshside dispersed towns, grew significant quantities of maize and other domesticated crops (at least late during the Irene period), and maintained a complex chiefdom level of social organization with centralized, inherited leadership and long-distance trade networks with the interior (Thomas, 2008: chap. 35).

Fig. 1.3. Position of growth surface within major increments at time of harvest: modern control sample of Mercenaria collected between 1975 and 1984 on St. Catherines Island.

Fig. 1.4. Map of probable seasonality on St. Catherines Island during the Irene period.

BUT DID THE JESUITS GET IT WRONG?

Given the compelling evidence for supporting low residential mobility and significant maize cultivation among the coastal Guale people, one must ask: What happens to the French and Jesuit accounts? These eyewitness accounts consistently describe high residential mobility, seasonal dispersal, infertile soils, and minimal horticultural productivity during the 1560s along the central Georgia Bight.

Did the Jesuits and the French simply get it wrong? Probably not.

Blanton and Thomas (2008) discussed the relevance of recent paleoclimatic research on bald cypress (Taxodium distichum) in the American southeast (Stahle and Cleaveland, 1992; Anderson, 1994: 277–289; Anderson, Stahle, and Cleaveland, 1995; Stahle et al., 1998; Blanton, 2000, 2004). The period of extended dryness during the latter part of the 16th century is particularly relevant to the present discussion—a time when “megadrought” conditions plagued much of North America (Stahle et al., 2000). During the early European contact period, Stahle et al. (1998: 545) document “a prolonged drought from 1562 through 1571 that was most severe from 1565 to 1569.” Whereas this intensely warm and dry interval (between about a.d. 1565 and 1569) has been little discussed in the recent literature, it signals an extraordinarily difficult time for forager–farmers along the Georgia coastline—one of many challenges facing Europeans and Native Americans alike. We can now see that the Jesuit missionaries of Georgia and Carolina were facing a prolonged drought, the driest interval of the entire 16th century (Worth, 1999; Saunders, 2000b).

Still smarting from their public failures in Spanish Florida, the Jesuit friars may have exaggerated their accounts regarding the poverty of the Georgia Bight (Jones, 1978, 1980; Worth, 1999). But when combined with the tree-ring evidence from this same area, these accounts gain considerable credibility because they document how these coastal chiefdoms adapted their normal seasonal and annual routines to accommodate environmental challenges and social stress.

Judging from the combined tree-ring records and surviving ethnohistoric accounts, it seems that the foraging farmers of Guale also adapted their provisioning strategies, sometimes using backup tactics to exploit relatively drought-resistant prey taxa. Additional research is required to understand how the logistic and residential strategies might vary in different localized landscapes across the Sea Islands and how they might respond to short-term climatic fluctuations—despite the fact that these coastal foragers pursued identical hunt types across identical patch types using identical technologies.[11]

Some Conclusions and Implications

This is where things stood with the publication of Native American Landscapes of St. Catherines Island (Thomas, 2008). We concluded that the modeling from human behavior ecology, newer ethnohistoric interpretations, and archaeological evidence from the island-wide survey were quite consistent with the Franciscan hypothesis: during the mid-16th century, Guale society was hierarchical and ranked, relying heavily on maize cultivation and centered on relatively high density, low-mobility “dispersed towns.” (i.e., the Franciscan hypothesis). But we did suggest that alternative, backup mobility strategies (consistent with the Jesuit hypothesis) seemed possible (even likely) during the dramatic drought episodes known to have taken place during the 16th and 17th centuries.

Since the publication of Native American Landscapes, we have continued intensive archaeological research on St. Catherines Island, pursuing two primary goals. One project flowed directly from our previous interest in the Guale problem. Emphasizing remote sensing and large-scale excavations, we are currently studying the settlement structure and household patterning at several late prehistoric (Irene) sites, especially Meeting House Field (9Li21). We think that these large sites are likely the “dispersed Guale towns” discussed by Jones (1978).

We have also launched a long-term program investigating the McQueen Shell Ring (9Li1648) and St. Catherines Shell Ring (9Li231), two large Late Archaic sites. The study of such Late Archaic rings has provoked lively discussions within the archaeological community (e.g., Russo and Heide, 2001; Marquardt, 2010a, 2010b; Russo, 2004, 2008; Sassaman, 2004, 2006; Thomas and Sanger, 2010). Ceramic production first occurs during the Late Archaic, spurring archaeologists to question the motives behind this technological advancement. Similarly, some of the earliest evidence for extended sedentism is found in such Late Archaic sites, begging questions into the cultural, sociological, and economic ramifications of such a shift in settlement pattern. The presumed planning and investment represented in Late Archaic shell rings also raises important questions regarding power, control, and hierarchy. With these issues in mind, we have conducted detailed mapping and extensive remote sensing operations at both sites, likewise excavating numerous test units and several large block excavations (Sanger and Thomas, 2010; see also Thomas and Sanger, 2010).

Although the Late Archaic and late precontact periods are separated by three millennia, both research designs require a thorough investigation of site seasonality. This is why we believe it necessary to deconstruct and to improve upon our previous work on St. Catherines Island.

The St. Catherines Island Research Design

Previous approaches to site seasonality on St. Catherines Island can be improved in numerous ways. For one thing, we used ¼ in. screens throughout most of the island-wide archaeological survey.[12] As Reitz (2008: 656) and others have noted, the use of such coarse-grained recovery techniques discriminates against smaller taxa, especially the smaller fishes (Reitz and Quitmyer, 1988; Quitmyer and Reitz, 2006; Reitz et al., 2010: 54). We should note that in all our excavations since 1982, we have only used 1⁄8 in. (or finer) screens, and in many cases, the deposits were water-screened as well. In our analysis of incremental growth in Mercenaria, we failed to distinguish left from right valves, creating the possibility that some of the randomly sampled specimens came from the same individuals (thereby weakening the assumption of independent sampling). Although we have modified our procedures in subsequent research on St. Catherines Island, we cannot currently assess the degree to which these shortcomings have biased the estimates of site seasonality in the Native American Landscapes of St. Catherines Island (Thomas, 2008).

We also created certain analytical ambiguities when interpreting the specific incremental patterns observed in the Mercenaria samples recovered for seasonal analysis. When framing the temporal parameters for Native American Landscapes of St. Catherines Island, we generally followed Clark’s (1979) seasonal estimates, which divided the annual growth cycle into phases observable through thin-section microscopy: winter (mid-December through mid-March), spring (mid-March through mid-June), summer (mid-June through mid-September), and fall (mid-September through mid-December). For phases of fast growth, our gradations of the “white” zone were translated to stages of “opaque” growth (scaled from O1–3); for episodes of slow growth, our observations on the “gray” increments were expressed as increments of “translucent” zonation. Even though we significantly expanded the modern Mercenaria control sample beyond what was available to Clark and we switched over to the six-stage growth incremental criteria of Quitmyer et al. (1985), our regrouped and reconfigured seasonal boundaries remain imperfect. Specifically with reference to the St. Catherines Island control sample, we found that growth stages T2 and T3 were almost entirely coterminous. This means that T2 and T3 specimens significantly overlapped in samples collected between mid-August and mid-December. Because of this overlap, we felt it necessary to group these two incremental stages into a single analytical category (denoted as T2–3). Similarly, because we found almost complete temporal overlap in growth stages O1 and O2, we decided to group these readings into a single category, denoted as O1–2. This is why we employed a four-part subdivision of annual shell growth in Mercenaria from St. Catherines Island (Mayer and Thomas, 2008). This is an imperfect solution and more recent studies (e.g., Quitmyer, Jones, and Andrus, 1997; Andrus and Crowe, 2008; Thompson and Andrus, 2010) have employed more fine-grained and better-defined criteria, standards that need to be applied throughout the St. Catherines Island project.

Other issues of basic sampling also arise from the island-wide transect survey. By relying on probabilistic, randomized sampling strategies, we were attempting to maximize the observed variability while minimizing sampling bias (Thomas, 2008: chaps. 11 and 19). Specifically, we generated a large sample of archaeological sites and loci, deliberately sampling across the range of soil types, site sizes, and time periods. We did this by using systematic transects, excavating hundreds of 1 × 1 m test pits, augmented by a shovel-testing program. Shovel-testing was a relatively unfamiliar technique during the late 1970s, when we conducted the island-wide survey and, in retrospect, we should have significantly expanded the shovel-testing aspect of the survey (because, we believe, we overlooked many nonshell sites, thus biasing the overall representativeness of the sample).

Reitz (2008: 617) has already commented on the difficulties in computing Minimum Number of Individuals, for instance, in the “aggregated” samples resulting from the island-wide survey sampling. Similarly, with respect to assessing site seasonality, our strategy of test-unit excavation also introduced an unanticipated degree of bias. When an archaeological “locus” was discovered, we excavated several (usually four to eight) 1 m2 test pits, working in 10 cm levels and proceeding down into sterile deposit. We saved all cultural and zooarchaeological materials encountered, collecting potential 14C samples in the process. We have already discussed the biases introduced by our selection procedures in radiocarbon dating (Thomas, 2008: 442–446). Specifically, when we examined our motives in sampling the radiometric record of St. Catherines Island, we found a significant bias created by our two rather basic sampling strategies, attempting to pinpoint chronostratigraphic central tendencies and trying to define the temporal range of ceramic variability. We concluded that the very process of selecting appropriate radiocarbon samples introduced a significant, nonrandom bias into the cumulative 14C histogram of all available radiocarbon dates, likely influencing our attempt to define the temporal range of ceramic time-markers. This bias could readily result in peaks that correspond to the middle range of a ceramic type and a gap separating temporally contiguous ceramic types.

Accordingly, in 2006, we processed an additional 49 radiocarbon determinations from contexts in the island-wide survey, attempting to “close the gaps” introduced by such biased sample selections (Thomas, 2008: 451–474). Among other findings, we ran 15 additional 14C samples, each apparently associated with fiber-tempered ceramics. Surprisingly, only 40% of these determinations fell into the expected age range, with more than half of the marine shell samples producing significantly later ages than the St. Simons period. We know this bias is unidirectional because none of the additional 34 samples associated with later ceramic types produced St. Simons age dates (Thomas, 2008: chap. 16). In other words, there is a clear-cut tendency of St. Simons period ceramics to be commingled with marine shell from later time periods. Many of the marine shell samples apparently associated with St. Simons and early Refuge-Deptford period ceramics actually produce much later 14C age estimates. This systematic error seems to reflect the general lack of shell deposits dating to the time span 1350 cal b.c.–200 cal b.c. (despite the presence of fiber-tempered and Refuge-Deptford period ceramics). The presence of Woodland period molluscs associated with Late Archaic ceramics creates obvious interpretive difficulties and biases when assessing matters of site seasonality.

We now believe that similar biases could have been introduced in our analysis of growth increments in hard clams. Earlier in this chapter, we reiterated the randomized procedures used to select specific Mercenaria for analysis. By deliberately attempting to assure “a relatively uniform distribution of hard-shell clams” (O’Brien and Thomas, 2008: 490), we likely “averaged out” some of the seasonal variability we were seeking. That is, we probably introduced some bias, as we did when selecting only “top and bottom” samples for 14C dating biased the macrochronological profiles resulting from radiometric dating. We think the sample selection process for Mercenaria probably skewed some of the resulting seasonal estimates for certain sites.

In subsequent fieldwork, we have emphasized the importance of defining microstratigraphic units for both radiometric and seasonality sampling, attempting to process multiple samples throughout these small-scale units (encountered in both large-scale excavations and column samples). In this way, we hope to avoid the problem of “averaging out” the variability we are seeking.

Correlative problems arise with modern techniques of isotopic analysis. As the results in seasonality studies become increasingly sophisticated and fine grained, we run the risk of “learning more and more about less and less.” As the precision increases, sample sizes become progressively smaller, raising the risk, again, that we are seriously underestimating the seasonal variability we are seeking. Ideally, the fine-grained, small-sample methods of isotopic analysis can be balanced against the larger-scale (if less precise) methods of growth increment documentation. Thompson and Andrus (2010) provide an excellent example of this procedure in practice, and we believe that their research provides a model for increasing precision while simultaneously addressing the need for maintaining large sample sizes.

Potential Problems with Proxy Populations

Modern control samples are critical as proxy populations for calibrating estimates of seasonal harvest in the remote past. The control sample of Mercenaria collected in the waters surrounding St. Catherines Island has some obvious strengths and weaknesses (O’Brien and Thomas, 2008: 481). Because the Mercenaria were collected over a nine-year interval, we hoped that this “longitudinal aspect” would help buffer the skewing effects of unique seasonal events, such as phases of exceptionally cold or warm temperatures, spawning, or storms. Because the control sample was collected in conjunction with ongoing archaeological fieldwork, the collection was particularly strong for the late winter and spring months; but our sampling strategy was sporadic and somewhat seasonally biased, especially during the summer months, when our archaeological field crew was generally deployed elsewhere for fieldwork, and also during the middle winter months, when we rarely excavated on St. Catherines Island. More recent studies (e.g., Quitmyer, Jones, and Andrus, 1997; Andrus and Crowe, 2008) have demonstrated the value of collecting larger, more systematic samples. Several chapters in this volume report on more recent research that has considerably improved the modern control sampling on St. Catherines Island.

Use of proxy population studies is also important when employing nonhuman vertebrate remains to reconstruct seasonality, on St. Catherines Island and elsewhere. Although noting that sharks and sea catfishes are expected to be relatively abundant during warm weather and are relatively rare in colder weather, Reitz (2008: 660–663) cautioned that “Vertebrates are not the best seasonal indicators … the absence of a seasonal marker can in no way be interpreted as evidence that the site was unoccupied at that time (Reitz and Wing, 1999: 259–261) … As with most research, negative evidence is not helpful.” There are also biases in preservation that militate against the recovery of juvenile specimens.

When estimating postencounter return rates for fish species common to the Georgia coast (Thomas, 2008: 113–135), I relied heavily on fisheries studies (esp. Dahlberg, 1972, 1975), significantly augmented by ichthyofaunal surveys conducted for a dozen years (on a monthly basis) on St. Catherines Island under the direction of Bruce Saul, of Augusta State University (Saul, 2002, 2003, 2004). In Native American Landscapes of St. Catherines Island, I discussed the seasonal availability of hardhead (Arius felis) and gafftopsail (Bagre marinus) catfish, noting Saul’s concern about the declining numbers between 2002 and 2004. Three years later, both catfish had virtually disappeared from the waters surrounding St. Catherines Island (Lambert, 2007; Bruce Saul, personal commun.). This surprising turn of events prompted Lambert (2007) to ask “where have they gone and why?” Perhaps this is a short-term natural cycle, or maybe a virus took out the population. Pollution is an obvious possibility, with some speculating that perhaps intake of heavy metals might be responsible.[13]

Whatever the cause, the mysterious disappearance of catfish near St. Catherines Island underscores the complex ecological dynamics involved in collecting control (proxy) samples for site seasonality studies. It is a mistake to assume that any single “modern collection” is an accurate proxy reflection of species biogeography or pattern of seasonal distribution. There are also issues, I believe, that must be addressed with respect to all aspects of control/proxy collections.

Consider, for example, the problems of changing hydrological regimes and their impact on levels of seawater salinity. Based on soil distributions and the dendritic pattern of relic groundwater outflows that once drained St. Catherines Island, Hayes and Thomas (2008) reconstructed a large freshwater lagoon they believe once dominated the central reaches of the island (see also Bishop et al., 2007: 40, fig. 6). During the aboriginal period, freshwater was always abundant on St. Catherines, available in numerous places, except during periods of extreme drought. The extensive central depression was powered by the Floridan aquifer, one of America’s most productive groundwater reservoirs, which extends from South Carolina to Florida and reaches inland as far as Alabama. The deep confined aquifer discharged artesian water to the ground’s surface in many places, and elsewhere, a relatively shallow well could tap the surficial reservoir of nonartesian water.

This was the hydrological regime available to the first St. Catherines islanders. Discharge from this system remained in approximate equilibrium so long as the upper Floridan aquifer was recharged by rainfall in the interior of the coastal plain, where it lay near the ground surface. These artesian conditions created natural seeps, with water flowing to the surface in springs and seeping into rivers, ponds, wetlands, and other surface-water bodies throughout most of coastal Georgia. But over the past century, groundwater pumping has significantly lowered the water level in the upper Floridan aquifer throughout the entire coastal area.

Recent research at colonial Jamestown (VA) highlights the potential of studying estuarine drought conditions by coupling fine-grained archaeological and paleoclimatic investigation (Harding et al., 2010). By comparing bivalve geochemistry (particularly oxygen isotope data) between modern oysters to those discarded in early 17th century wells, these investigators have successfully quantified estuarine salinity, seasonality of oyster collection, and annual shifts in drought conditions in the Chesapeake Bay ecosystem.

It is difficult for the modern observer to appreciate the magnitude of the hydrological change over this past century. But by looking closely at the historical sources and tracing out the surviving geomorphological evidence, we believe it is possible to reconstruct what St. Catherines Island looked like before the deep drilling so significantly changed the hydrology.

We think that shifting hydrologies over the past century have significantly impacted the American (or eastern) oyster, Crassostrea virginica, still found in abundance within intertidal estuaries, along saltwater rivers and tidal creeks that dissect the expansive Spartina marsh. Within a given locality, oyster growth depends on bottom conditions, degree of salinity, water temperature, and tidal movement. A century ago, coastal Georgia was among the world’s leading oyster harvesters, rivaling the celebrated, oyster-rich waters of the Chesapeake (e.g., Irving, 1902; see also Thomas, 2008: chap. 7): By the 1880s, overharvesting and pollution threatened Georgia’s shellfishery. The headwaters of these oyster-bearing rivers were also once fed by freshwater aquifers, which dried up due to the lowering of water tables over the past century. Walker and Cotton (2001) suggest that this loss of freshwater headwater could account for gradual movement of oysters away from places like the Duplin River (off St. Simons Island) over time.

Cannarozzi and Quitmyer (2007) have discussed the monthly collection of oysters from St. Catherines Island, continuing since 2006. As these modern control samples are amassed for isotopic study, one must wonder about whether shifting hydrological and salinity patterns could have impacted the biochemical processes in modern oysters. There is also the possibility that ongoing global climate change—especially with respect to sea level and water temperature—could impact modern oyster growth patterning.

One potential avenue of inquiry into molluscan proxy populations might be available through the study of century-old bivalves. In Native American Landscapes of St. Catherines Island (Thomas, 2008: chap. 13), we discussed the issues surrounding reservoir correction calculations, and the necessity of obtaining known-age, prebomb mollusc samples for 14C dating. We knew that a commercial oyster industry had once flourished in the waters surrounding St. Catherines Island (Thomas, 2008: chap. 6). In the late 19th century, Augustus Oemler erected an oyster factory on the south end of St. Catherines Island. Oysters, collected by hand from nearby creeks and marshes, were prepared in a large boiler connected to the southern end of the island by a causeway. Two additional boilers were added later. The apparently inexhaustible supply of oysters disappeared during the 1920s, forcing the once flourishing oyster factories of St. Catherines Island to close. Today, the rusting boilers and massive spoil heaps of oyster shell remain visible evidence of this industry. Since virtually all of the shells within these factory middens derived from Crassostrea individuals harvested between about 1900 and 1920, we collected numerous samples and used them in the reservoir correction computations for St. Catherines Island.

We think that a similar approach might be useful in considering the effects of hydrological change and shifting salinity over the past century. Not only could we collect oysters that lived under the previous (artesian) hydrological regimen, but we have recently discovered that occasional Mercenaria were also (accidentally) harvested at the oyster factories, providing another potential source of samples to explore this issue. For St. Catherines Island (and the rest of the Georgia coastline), we have detailed salinity measurements taken between October 1888 and February 1889 (Drake, 1891). We think a comparison of modern and century-old salinity levels and mollusc proxy samples could help determine the nature of recent hydrological and salinity shifts over the past century. It might be that the century-old molluscs provide more accurate “modern controls” than proxy specimens collected in the past few years (see Thomas, n.d., for more recent data on this issue).

We pose these two case studies to suggest some potential new refinements in site seasonality studies. For decades, reconstructing site seasonality has been the warp and the weft of St. Catherines Island archaeology. So far, so good (I believe). But we must do much better … and that’s what the Fifth Caldwell Conference is all about.

CHAPTER 2: A BAYESIAN CHRONOLOGICAL FRAMEWORK FOR DETERMINING SITE SEASONALITY AND CONTEMPORANEITY

Douglas J. Kennett and Brendan J. Culleton

In the previous chapter, Thomas outlined a multiscalar approach for determining seasonal resource exploitation strategies and, by extension, for reconstructing mobility patterns in the past. On St. Catherines Island this involves: (1) ceramic typologies for establishing submillennial temporal resolution (the hour hand); (2) radiocarbon dating to control century-level resolution (the minute hand); and (3) site seasonality studies to provide seasonal or monthly resolution (the second hand). This hierarchy of chronological measures is essential when inferring mobility patterns from seasonality data from multiple sites. The crux of the matter is whether or not sites used during different or the same seasons are coeval. Chronology really does make a difference when interpreting seasonality data and inferences regarding prehistoric mobility patterns. If changes in mobility and resource extraction are detected, then finer grained chronological information is also required to determine if these changes were influenced by paleoenvironmental change and/or other mechanisms (e.g., population growth, resource intensification, or competition for resources).

In this chapter we argue that a Bayesian statistical environment provides a coherent framework for integrating these multiscalar chronological measures. The Bayesian analysis of radiocarbon dates from archaeological sites is now becoming routine in Britain (Bayliss and Bronk Ramsey, 2004; Buck, 2004; Bayliss et al., 2007) and programs like OxCal (Bronk Ramsey, 1995, 2001, 2005) provide a prepackaged set of Bayesian statistical tools to help develop more robust archaeological site chronologies. Custom-built Bayesian statistical environments to analyze and model spatiotemporal patterns in the archaeological record are also being developed including tools potentially useful for integrating the multiscalar chronological measures necessary for establishing site seasonality and inferring mobility patterns (Buck, 2004; Steele, 2010; Winter-
halder et al., 2010). In this chapter we emphasize the development of a Bayesian chronological framework for interpreting seasonality data on St. Catherines Island. We begin with a basic overview of the approach.

Bayesian Essentials

Classical statistical analysis has dominated archaeological inquiry and is well suited to a wide range of observations made by archaeologists (Thomas, 1986; Shennan, 1997; Drennan, 2010). However, there are certain contexts where a Bayesian approach may be better suited and we argue that the types of data acquired in seasonality studies fall into this category. In contrast to classical statistics, Bayesian statistical analysis derives posterior information (a posteriori) by combining prior information (a priori), a likelihood function (a particular probability function), and the available data (Buck and Millard, 2004b: VII). The best examples in archaeology come from chronology building where a variety of nonquantitative contextual information (e.g., stratigraphic position, diagnostic artifact assemblages) can be integrated with probability distributions from radiocarbon dates (Bayliss and Bronk Ramsey, 2004; see below).

Emphasis is placed on chronological model building based on prior knowledge and the available radiocarbon dates followed by iterative data collection to make adjustments. The major benefits of this approach are that: (1) a statistical environment is created that incorporates a wider range of observations and knowledge (e.g., relative and absolute chronology), and (2) these models can be used to direct research and make sampling decisions. Using a priori information can make some researchers uneasy (see Steier and Rom, 2000), but if care and transparency are used it provides a framework to formalize assumptions and to build and test multiple models with new data. Shell middens are particularly complex (Stein, 1992), but agreement indices (A) provide a way of determining how each alternative model fits with the available data, and are generated for the posterior distributions of each radiocarbon date in a model, as well as the overall model itself (Bronk Ramsey, 2000: 201). Agreement indices falling below a critical value (A’c = 60%) indicate a poor fit of data with the model, and can be used to identify potential outlier dates or problematic stratigraphic assumptions in the model. It should be noted that, strictly speaking, when A > A’c (i.e., there is agreement between model and dates) it does not mean that the model assumptions and structure are correct. It simply tells us that we have no reason based on the data at hand to reject the model as it stands.

Building Site Chronologies

The first step in developing a coherent picture of site seasonality is establishing a viable chronology and determining the contemporaneity of different sites. When combined with seasonality data this allows for the reconstruction of changing patterns of resource extraction at one location. Broader patterns of settlement and land use are often inferred from these data when combined with other regional datasets. The accurate reconstruction of mobility patterns at the regional level is dependent upon whether sites were used or occupied during the same interval. This highlights one of the first-order decisions necessary when building a Bayesian chronological model for seasonality studies: finding a meaningful definition of contemporaneity (Bayliss and Bronk Ramsey, 2004). On St Catherines Island this could be defined as the “Archaic period” or it could be taken to be the same century or even the same decade.

The hypothetical example in figure 2.1 demonstrates the importance of high-precision dating for interpreting seasonality data. The low-resolution site chronology displayed in the first panel (A) shows six “contemporary” sites dating to between a.d. 800 and 1000. The one larger village site shows evidence for hard clam (Mercenaria) exploitation and processing during all seasons along with evidence for a variety of other activities. The five other sites are more ephemeral shell middens showing hard clam harvesting and processing during different seasons. One interpretation of this would be year round occupation of the larger site with logistical exploitation of hard clams throughout the year by a certain segment of the larger social group (B). A finer grained chronology is shown in panels C and D, revealing an alternative model of higher residential mobility between a.d. 800 and 900 followed by greater sedentism at one locality between a.d. 900 and 1000. The combination of high-resolution chronological and seasonality data has a major impact on the socioeconomic and evolutionary inferences made from these data.

Establishing precise chronologies is no simple matter and is done best within a Bayesian statistical framework. English Heritage has used the approach since the mid-1990s as a cost effective way of building site chronologies (Bayliss and Bronk Ramsey, 2004). The computer program OxCal provides a preexisting Bayesian environment to build and refine chronologies. Model building and testing is completed in an interactive fashion with new data informing and refining chronological models for individual sites. Precise dating is dependent upon: (1) careful stratigraphic excavation and the exact recording of 14C samples within the depositional sequence, (2) the selection of short-lived organisms for AMS radiocarbon dating (e.g., carbonized seeds, twigs, marine shells, or animal bones), (3) proper chemical protocols for processing samples, and (4) an understanding of taphonomic processes affecting potential radiocarbon samples. Outdated radiocarbon dates with high error ranges from previous excavations may be used as an initial guide for model development along with stratigraphic information. They may contribute to the final chronological model, but they could also be eliminated as outliers. This is largely dependent upon the research question being asked. When high precision is required, as is the case with seasonality studies, it is often necessary to start over with a clear idea of site stratigraphy, sample types and locations, and the low analytical error afforded by adaptations to the latest generation of Accelerator Mass Spectrometers (Beverly et al., 2010). Even with the best technological and procedural protocols in place, chronological control is ultimately constrained by the vagaries of the calibration curve, which afford different levels of precision throughout time depending upon atmospheric radiocarbon production and ocean circulation (see e.g., Blackwell, Buck, and Reimer, 2006).

Fig. 2.1. Hypothetical seasonality and settlement data (A) along with differing interpretations of these data based on low (B) and high (C and D) resolution chronologies for these sites.

Trimming Confidence Intervals

We start with a simple advantage afforded by Bayesian analysis: the trimming of calibrated 14C radiocarbon confidence intervals using the stratigraphic position of samples. This is based on the simple combination of relative and absolute chronological information. The variety of factors influencing measurement errors in radiocarbon dating and fluctuations in the calibration curve can result in substantial overlap of calibrated distributions even if two events are known not to be contemporary based on the stratigraphic record. Take, for example, two radiocarbon dates on charred hickory nuts from the McQueen Shell Ring on St. Catherines Island, table 2.1: one near the base of the shell midden deposit (Beta-251767; 3680 ± 40 b.p., N243E233; 40 cmbs) and the other closer to the top (Beta-251761, 3710 ± 40 b.p., N243E233; 10 cmbs) (Sanger and Thomas, 2010). The calibrated 2σ probability distributions for these two dates broadly overlap (outlined probability distribution in fig. 2.2), but from the law of superposition we can argue that the lowest part of the sequence accumulated first, followed by the upper materials. This stratigraphic information can be used to create a posteriori distributions for these same dates (filled probability distributions) that assume that the hickory nut at 40 cmbs must be older than the one at 10 cmbs. The model fit with the data satisfies the threshold for acceptance (A = 99.9%, A′c = 60%). In other words this model is viable and indicates that this part of the deposit accumulated rapidly between 2100 and 2000 cal b.c.

Probability distributions of marine shell dates from the same deposit show a similar story (see table 2.1). The upper two dates are associated with the radiocarbon dates on charred hickory nuts and the third date is stratigraphically below the lowest of the two. The calibrated probability distributions of these dates also overlap in figure 2.3. Applying the same stratigraphic assumptions as above, the calibrated probability distributions are trimmed and the dates fall into an acceptable stratigraphic order between 2100 and 1900 cal b.c. (A = 83.8%). The smoother probability distributions and larger calibrated ranges for marine shell, relative to associated carbonized seeds, result from the mixing model used to derive the Marine09 calibration curve from the IntCal09 atmospheric curve (which, for most of the Holocene, are identical to the 2004 versions), and propagation of uncertainty in the ΔR estimate (following Stuiver, Pearson, and Braziunas, 1986).

Considering the same three dates in two additional contexts can show the importance of reasoned stratigraphic interpretation for forming the priors in Bayesian chronological modeling. First, let’s say that we had reason to infer that the entire deposit was laid down in one event, or for practical purposes within a single year or a few years. In that case we would assume that all the shells should be the same age, and scatter in conventional 14C ages arises from simple measurement error. These dates could then be combined following the procedure of Ward and Wilson (1978), with a resulting averaged age of 3860 ± 25 b.p. A chi-squared test indicates that there are no outliers in this group of dates (χ2 = 2.757; df = 2; T’ = 5.991) and we can infer that the shells were deposited sometime between 2180 and 1930 cal b.c. (at 2σ). Alternatively, if the stratigraphic relationships among the three dates were unclear in the field, the dates could be modeled as a phase rather than a sequence, with boundaries placed as estimates of two undated events: the start and end of shell deposition. Modeling as a phase might be more appropriate for dates within a stratum that appears to be distinct and in order within the larger stratigraphic sequence, but could have been mixed before being buried. Another application would be dates from multiple discrete shell lenses or hearths deposited on a common living surface, where the depositional order among them cannot be discerned from the stratigraphy. If the three shell dates are modeled as an unordered phase, we find that the stratum was deposited over a span potentially as long as 800 years, from ca. 2600 to 1550 cal b.c. (A = 105.9%). All that differs between these three scenarios are the prior assumptions that are used to model the three shell dates: the first assumes an ordered stratigraphic sequence; the second assumes a single deposition event; the third assumes an unordered group of dates, or a phase. That the resulting chronological data can differ so greatly based on a simple assumption drives home the fact that proper stratigraphic interpretation in the field is of primary importance. The agreement indices provide no guidance in these scenarios as to which assumptions are more reasonable (nor does Ward and Wilson’s χ2 test), so it rests upon the fundamental archaeological skill of interpreting stratigraphy and site-formation processes.

Fig. 2.2. Calibrated results of a sequence of two 14C dates on hickory nuts from McQueen Shell Ring using OxCal 3.01. Standard calibration is shown in open outline (prior distribution); modeled calibration incorporating stratigraphic information (posterior distribution) is depicted as a solid fill. The agreement index (A = 99.9%) above the critical value (A′c = 60.0%) indicates good agreement between the data and the model.

Fig. 2.3. Calibrated results of a sequence of three 14C dates on Mercenaria shells from McQueen Shell Ring using OxCal 3.01. Standard calibration is shown in open outline (prior distribution) and modeled calibration incorporating stratigraphic information (posterior distribution) is depicted as a solid fill. The agreement index (A = 83.8%) higher than the critical value (A′c = 60.0%) indicates good agreement between the data and the model.

TABLE 2.1: Radiocarbon Dates from McQueen Shell Ring, N243E233

Beta no.

Provenience(1)

Material

Conventional 14C age

2σ cal age

2σ cal age as sequence

2σ cal age as phase

251761

4.5–4.4 m

charred hickory nut

3710 ± 40

2280–1970 b.c.

2150–1960 b.c.

251767

4.4–4.3 m

charred hickory nut

3680 ± 40

2200–1940 b.c.

2210–2030 b.c.

251762

4.5–4.4 m

Mercenaria shell

3820 ± 50

2180–1850 b.c.

2100–1820 b.c.

2150–1880 b.c.

251768

4.4–4.3 m

Mercenaria shell

3910 ± 40

2280–1960 b.c.

2150–1940 b.c.

2220–1940 b.c.

251769

4.3–4.2 m

Mercenaria shell

3830 ± 40

2160–1870 b.c.

2210–1980 b.c.

2150–1900 b.c.

(1) Note that elevations are above an arbitrary 0 m datum.

Toward Building a Bayesian Model for the McQueen Shell Ring

Funding is often limited for archaeological projects and precision AMS radiocarbon dating is expensive. How precise a chronology needs to be is directly related to the research question at hand and for site seasonality, high precision is generally required if the ultimate goal is to reconstruct mobility patterns. Seasonality studies themselves are also time consuming and expensive. It makes sense to establish a precise site chronology prior to conducting seasonality work in order to define the relevant sampling units and to avoid oversampling a particular interval at the expense of other units that may be more interesting or significant chronologically.

Figure 2.4 shows the north wall profile of a unit excavated on the eastern side of the McQueen Shell Ring (N243E233). The sequence is between 40 and 50 cm deep in this area and dominated by a dense deposit of shell (~30 cm thick) overlying a medium brown sand containing no shell and a thinner deposit of shell and bone (labeled clam “floor”). The samples discussed above come from the thicker shell deposit and their stratigraphic position is shown along with our first attempt at building a chronological model for this part of the site. In this model the dates are ordered in a sequence and the start and end dates for the sequence are modeled from the available data. Marine shell samples are available for dating from the shell deposit and the clam “floor” and ongoing work will determine if charred seeds or twigs will also be available for study. In certain contexts 14C dating marine shell is preferable to other materials and it is often the only material available from certain stratigraphic contexts (Kennett et al., 2002; Thomas, 2008). It is also short-lived and material deposited during a single year or season can be sampled (but see Culleton et al., 2006, for complicating factors in areas with high upwelling).

This Bayesian chronological framework provides a guide for future work. One or two dates are needed to determine the age of the clam “floor” and they will help constrain the age of the intervening sterile medium brown sand lens (along with the shell date just above it [Beta-251769]). An additional date from the uppermost layers in the shell deposit will help constrain the terminal age of the deposits in this part of the site. Dating a marine shell may be preferable in this instance due to the contamination of surface deposits with modern carbonized plant material (see discussion of precision below). The presence of pitting in other parts of the site suggests horizontal stratigraphy that should also be explored with additional dates. The decision to add more data to the modeled chronology is based on the ability of new data to refine the model. The method calls for continued AMS radiocarbon dating of quality materials from known stratigraphic units until the model can no longer be improved. In reality, there is often a trade off between model quality (precision and accuracy), available funds, and time to publication.

Fig. 2.4. Profile of the N243 trench north wall, McQueen Shell Ring (AMNH 696, 9Li1648), showing the depositional sequence discussed in the text (courtesy of Matt Sanger). O high organic, dark brown sand; Ap plowed A, dark brown sand, shell flecking; A2 buried A, dark brown, no shell; B medium yellow brown, no shell; MBS medium brown sand; SD shell deposit.

A Note on Precision 14C and Seasonality Studies

The larger age ranges evident in the marine shells from the McQueen Shell Ring point to the importance of precision and accuracy in building site chronologies. Radiocarbon dates with large analytical error reflect poor precision, but also undermine accuracy by increasing the range of actual calendar ages that could produce the measured age. This compromises our ability to determine if two sites with seasonality data are contemporary or not. One crucial way in which this occurs can be illustrated with the Ward and Wilson test described earlier, which is essentially a test of contemporaneity between conventional 14C ages. Taking two McQueen shell dates, Beta-251769, 3830 ± 40 b.p., and Beta-251768, 3910 ± 40 b.p., the χ2 test does not reject the sample as containing outliers, so they may be contemporary (χ2 = 2.000; df = 1; T’ = 3.841). However, if the same dates had better precision, say ± 20 14C yr, the same two dates are strongly rejected as unlikely to be contemporary (χ2 = 8.000; df = 1; T’ = 3.841). Put simply, low-precision dates are more likely to appear contemporaneous, even with a generally robust statistical test, than high-precision dates. Although Stuiver, Pearson, and Braziunas (1986) have argued that the relative smoothness of marine calibration curves (caused by propagating multiple layers of statistical uncertainty) reduces “wiggles” and the frequency of multiple intercepts, it is at the cost of wider calibrated ranges that make it more difficult to distinguish true contemporaneity. Analytical precision can be improved with modifications to the latest generation of Accelerator Mass Spectrometers (Beverly et al., 2010). Samples in the age range of the McQueen Shell Ring could be reduced to ± 15 and 20 14C years with this approach (Kennett et al., 2011). However, the precision and accuracy of marine samples will always be lower than paired terrestrial samples because of the mixing models and the ΔR estimates used in the calibration process.

Bayesian statistical tools may provide one possible way of improving the precision and accuracy of marine shell dates to make them more comparable to terrestrial samples. The approach would rely on the visible and predictable incremental changes in hard clam (M. mercenaria) shells and the “wiggles” in the marine calibration curve. Visible incremental change in the growth of hard clams has already provided an important source of seasonality data on St. Catherines Island (O’Brien and Thomas, 2008). The benefits of working with hard clam shells include their ubiquity in island archaeological deposits of all ages, the resistance of their thick shells to decomposition, and a clear growth structure that responds to water temperature and associated changes in the marine system in predictable ways. These same characteristics provide an opportunity for precision AMS 14C dating and therefore a link between the centennial resolution of radiocarbon dating and the seasonal or monthly data provided by seasonality studies.

If greater precision and accuracy are required to establish a chronological model for an archaeological site, then additional AMS 14C dates within the same hard shell can be combined with the counting of annual growth increments to obtain a more precise age. The known chronological separation between samples based on ring counting is incorporated into OxCal and a defined sequence is used to “wiggle match” the radiocarbon ages to the calibration curve to improve precision and accuracy (Bronk Ramsey, van der Plicht, and Weninger, 2001). This approach has been used to obtain a very precise and accurate age on a prehistorically constructed subcircular ring of oak timbers discovered in the intertidal zone in Norfolk, England (Bayliss et al., 1999). In the Norfolk case, six contiguous samples of 20 years’ growth were precisely dated and a Bayesian model incorporating these dates and the known gaps between them was used to establish the date of construction at 2050 cal b.c.

In the case of hard clams on St. Catherines Island, the time elapsed between radiocarbon samples in a single hard clam shell can be determined with annual growth increments. Modern specimens from protected areas along the southeastern coast are known to live up to 30 years (Ansell, 1968; Quitmyer and Jones, chap. 7, this volume), but the maximum age of individuals from prehistoric contexts on St. Catherines is about 10 years with most in the 3–4 year range (see fig. 7.9 in Quitmyer and Jones, this volume). This increment just satisfies the minimum required to match the resolution of the calibration curve (3–4 years; Bronk Ramsey, van der Plicht, and Weninger, 2001: 388). Hard clam shells are composed of alternating white (opaque under tungsten light) and dark (translucent under tungsten light) bands that represent sequential annual cycles. Growth rates are faster in winter and spring (white growth) and slower during the summer months (dark growth). Water temperature and associated biotic shifts appear to influence growth rates (Henry and Cerrato, 2007; Jones, Arthur, and Allard, 1989; Jones and Quitmyer, 1996; Quitmyer and Jones, chap. 7, this volume, Cannon, and Jones, 1985; Quitmyer, Jones, and Arnold, 1997) and this has been confirmed with stable isotopic studies (Andrus and Crowe, 2008; Quitmyer and Jones, chap. 7, this volume). The growth rings are clearly visible and can be counted to determine a clam’s age at the time of harvest. A couplet of one opaque and one translucent increment represents one year of life.

Figure 2.5 shows a cross section of a fictitious hard clam shell displaying incremental growth. This clam was 10 years old when it was harvested during the winter (O1, white [opaque], December through January). From the perspective of seasonality, we are interested in establishing a precise age for this and associated hard clam shells. AMS 14C dating the carbonate near the terminal growth margin of the shell (sample A) will accomplish this, assuming that the marine reservoir does not fluctuate radically throughout the annual cycle as it does in other parts of the world (Kennett et al., 1997; Culleton et al., 2006). This assumption needs to be empirically tested, but it seems a reasonable working hypothesis since marine upwelling (a source of old carbon) along the coast of St. Catherines appears to be minimal given the bathymetry, and the negative local reservoir offset (ΔR = –134 ± 26 14C yr) indicates better than average mixing of atmospheric carbon compared to the global marine model age. We use a fictitious set of dates here based on the marine shell dates from the McQueen Shell Ring discussed above. The calibrated age of the terminal growth margin ranges between 2090 and 1960 cal b.c. (130 yrs at 1σ, shown as outline in fig. 2.5). Adding two additional dates (B and C) 5 and 10 years earlier in the growth of the clam creates a sequence of dates that can be used to wiggle match with the marine calibration curve to get a more precise age. In OxCal this is accomplished by creating a defined sequence with an established set of known age gaps based on counted growth increments (Bronk Ramsey, 2001: 383). The posterior or modeled age distribution for the terminal growth margin, based on wiggle matching, is reduced to 1980–1910 cal b.c. (70 yrs at 1σ, shown as a solid distribution in fig. 2.5). This is comparable in age to a carbonized seed of the same age and calibrated with the atmospheric calibration curve.

Running multiple AMS 14C dates on the same clam shell is costly and this would only be warranted if associated carbonized twigs or seeds were not available. However, marine shells are short lived, so dating the shells would be preferable to 14C dating wood charcoal or bulk sediments (see Sanger and Thomas, 2010, regarding problems with 14C dating bulk sediments). Depending upon the age of the shell, and the character of the marine calibration curve at that time, a substantial improvement may be obtained with just one additional measurement. In the case of wiggle matching, more wiggly parts of the curve are actually more of a boon than a bane because they constrain the match more tightly. To evaluate the potential for wiggle matching, terminal growth margins should be 14C dated first and then a defined sequence may be modeled with OxCal using that date plus a number of simulated dates at specified gaps to determine if (or how many) additional dates from the shell would be worthwhile (the above example was created in this way). The specific advantage of working with hard clams is that this provides a close linkage between the subcentennial scale precision of AMS 14C dating and the seasonal data provided by hard clam growth increment studies.

Fig. 2.5. Schematic cross section of a hypothetical Mercenaria valve showing annual growth increments and three 14C dates used in a defined sequence to wiggle match the terminal date (A). Results of the wiggle match, performed with OxCal 3.01, are depicted below. Standard calibrations are shown in open outline (prior distribution) and modeled calibrations incorporating known five-year gaps in the defined sequence (posterior distribution) are depicted as a solid fill.

Contemporaneity and Archaic Period Shell Rings

Most applications of Bayesian models for chronology building have focused on single locations where the relationship between samples is known and stratigraphic context is built into the model. The ultimate goal of most seasonality studies is to reconstruct prehistoric mobility across a landscape. This is dependent upon determining whether two archaeological sites are contemporary or not. More sophisticated models that add this spatial component are now being developed (Buck, 2004; Winterhalder et al., 2010), but these types of studies are in their infancy and require custom-built Bayesian statistical environments not available in prepackaged programs (e.g., OxCal).

As a starting point for work on St. Catherines, we investigate the contemporaneity of the McQueen and St. Catherines shell rings within a Bayesian statistical framework. Shell rings are relatively common in the American southeast and are often the oldest sites found in coastal regions (Russo, 2006). They generally date to the Late Archaic period (4000 to 1000 cal b.c.). Two of these shell rings have been identified on St. Catherines Island: the St. Catherines and McQueen shell rings. The St. Catherines Shell Ring is positioned on the west coast of the island and has been excavated extensively. A series of 14C dates are available for study (Thomas, 2008: 370). The McQueen Shell Ring is located on the east coast of the island and is currently being excavated, but preliminary results are now available for comparison (Sanger and Thomas, 2010: 62–63). A comparison of 14C summed probability profiles from these two sites suggests that both were occupied from ca. 2600 to 1800 cal b.c. However, the material culture differs substantially at these sites, particularly in the types of ceramic decorations identified and the relative proportions of groundstone and decorative items found at each site (Sanger and Thomas, 2010: 67). If the two sites are contemporary and seasonality studies demonstrate year-round occupation, then this observation has interesting social and political implications.

Summed probability distributions are useful heuristic devices and can be helpful in focusing research questions, though their statistical meaning actually remains poorly understood. We have no metric to evaluate how much overlap in two summed distributions constitutes contemporaneity or temporal disjunction. In the present case, it suggests the potential for simultaneous occupation of the two shell rings over a broad period, which runs counter to the observation of different material culture assemblages at each site that could suggest two temporally distinct occupations. With a Bayesian model, we can take the prior knowledge of the differing assemblages as a basis for arguing that one shell ring precedes the other, and there is no overlap in the occupations. At a first pass, we simply model the culturally relevant and reliable 14C dates from St. Catherines and McQueen as two phases (groups of unordered dates) within a sequence that forces the St. Catherines phase to precede the McQueen phase. The advantage to this approach is that an agreement index (A) is calculated that gives a measure of model fit, and provides a statistical basis for accepting or rejecting the model and its assumptions. Perhaps unsurprisingly, this model thoroughly fails to accommodate the data (A = 22.6%; A’c = 60.0%), which means we must reject the assumption of sequential and discrete occupations of each shell ring. While this may seem a minor insight in light of the overlap observed in the summed probabilities, it may also suggest that the differing cultural assemblages in each shell ring may not be as temporally diagnostic as thought, or that their associations with the dated materials could be reconsidered.

Further steps in refining this analysis depend on more detailed stratigraphic models for St. Catherines and McQueen shell rings. For St. Catherines the 14C dates that are acceptable (based on the excavators’ knowledge of the deposits) can be grouped into three categories: Pre-Ring; Ring; and Interior Plaza. The first two groups have an intuitive temporal relationship implied in their names, and the third represents a more temporally ambiguous group, where the spatial association with the rest of the shell ring doesn’t allow a firm stratigraphic argument to be made with respect to the other two groups of dates. Leaving the Interior Plaza aside for the moment, we can treat the Pre-Ring and Ring dates as phases in a sequence, similar to our treatment of St. Catherines vs. McQueen shell rings above. In this case, the assumed order is based on stratigraphic relationships rather than diagnostic artifact assemblages, but the model structure is similar. Boundaries are modeled representing the beginning of Pre-Ring deposition, the transition from Pre-Ring to Ring deposition (i.e., the initial construction of the St. Catherines Shell Ring), and the end of Ring deposition. The Interior Plaza dates can be grouped into a separate phase independent of the other two, with boundaries for its beginning and end. The results of these models are depicted in figure 2.6 and from the agreement index of A = 84.6% we can see that the assumption of all the Pre-Ring dates preceding the Ring dates appears to be a reasonable one, based on the data at hand. The boundaries, which are estimates of additional undated events, also provide interesting information. The start of Pre-Ring phase cultural deposition is placed at 3100–2450 cal b.c., the beginning of Ring phase deposition at 2430–2200 cal b.c., and the end of Ring phase deposition is at 2210–1780 cal b.c. The Interior Plaza phase overlaps considerably with both the Pre-Ring and Ring phases, being estimated to start between 2980 and 2500 cal b.c. and to end between 2400 and 1800 cal b.c. This result accords with descriptions of the Interior Plaza deposits as appearing to be more mixed, and potentially being a locus for deposition through both phases of site use.

The depositional sequence of the McQueen Shell Ring is in some ways more complicated. Focusing on a series of dates from three excavation units (TPII, N243E233, and N272E200), we can build a nested model of sequences and phases for the shell ring. The overall period of deposition is considered a phase, which includes an unordered group of three sequences comprising the dates in each unit. We do this because we are making no assumptions about the stratigraphic relationships between units, only within units. Within two of the unit sequences we have pairs of shell and charcoal dates in a few levels; these pairs are treated as phases within the unit sequences, again because they are unordered with respect to each other, though they both should postdate those below and predate those above. This is a somewhat involved model for a relatively small number of dates, but its structure actually reflects a fairly conservative set of stratigraphic assumptions, all of which are open to evaluation. Figure 2.7 shows the modeled results, and we are immediately alerted by a poor agreement index (A = 17.8%) for the overall model. Phase models are more accommodating than sequences, so we would expect the problems to lie in one of the three unit sequences, and from the individual agreement indices it’s clear that the upper and lower dates in TPII (A = 7.2% and 10.9%, respectively) are problematic. The dates in this unit appear to be completely reversed, and our assumed depositional sequence appears to be incorrect. This information could direct the excavators to reevaluate the context from which the dated shells were taken, sample selection criteria, or even to recheck the sample labels or artifact inventories. For the time being, however, we can revise the model by removing these three dates and see if it behaves differently.

Without the dates from TPII, the agreement index for the revised McQueen model is A = 85.4%, indicating a good fit between the observed data and the model. Also, the overall distribution of dates and boundaries is not greatly altered by removing the three problematic dates, other than making the boundary estimates for the beginning and end of deposition a bit broader, as they are constrained by fewer dates. The start of McQueen Shell Ring deposition is estimated between 2520 and 2100 cal b.c., and the ending between 1970 and 1580 cal b.c., which overlaps substantially with the Ring phase at St. Catherines (starting at 2430–2200 cal b.c.) though McQueen likely persisted past the end of the Ring phase as currently modeled. If the set of McQueen dates included in the model is representative of the site, it would appear that there is no occupation contemporary with the St. Catherines Pre-Ring phase at McQueen. Further dates from McQueen and a refined stratigraphic picture may improve our interpretations, both by constraining the depositional boundaries and adding more relationships between dates in the various excavation units, which should provide a more detailed sense of occupational changes through time.

Fig. 2.6. Two sequences incorporating the most reliable 14C dates from the Archaic in St. Catherines Shell Ring. The first models two phases (unordered groups of dates) defined as “Pre-Ring” or “Ring” within a sequence that assumes no overlap between the two phases and are separated by a boundary. Standard calibration is shown in open outline (prior distribution) and modeled calibration incorporating phase designations (posterior distribution) is depicted as a solid fill. The agreement index (A = 84.6%) higher than the critical value (A′c = 60.0%) indicates good agreement between the data and the model. Below, a third group is placed in an independent phase of Interior Plaza dates, with boundaries to estimate the beginning and end of that phase of deposition. Substantial overlap with both Pre-Ring and Ring phases supports the view of continued deposition in the Interior Plaza in both phases. See Sanger and Thomas, 2010, for raw data.

Fig. 2.7. A phase of nested sequences incorporating the most reliable 14C dates from the Archaic in McQueen Shell Ring. Dates from within individual units can be placed in sequences based on their stratigraphic relationships, but the three units cannot be cross-correlated, so they are collectively modeled as an unordered group of sequences, i.e., a phase. Standard calibration is shown in open outline (prior distribution) and modeled calibration incorporating phase designations (posterior distribution) is depicted as a solid fill. The agreement index (A = 17.8%) well below the critical value (A′c = 60.0%) indicates poor agreement between the data and the model. Low individual agreement indices point to reversals in unit TPII, which should be removed from subsequent analyses and the context reconsidered in the field. See Sanger and Thomas, 2010, for raw data.

Conclusions

Seasonality studies depend upon defining culturally meaningful analytical units and analyzing and interpreting seasonality data within the broader context provided by these units (Monks, 1981: 223). Chronology building is an essential part of defining these analytical units. We argue that the Bayesian approach defined in this chapter provides a viable statistical framework for combining stratigraphic information and other prior knowledge with radiocarbon dates to establish more precise and accurate chronological models for archaeological sites on St. Catherines Island. It also provides a set of tools and indices for determining if the various sites on the island are contemporary or not, critical information when comparing seasonality data and inferring past land use and mobility patterns.

One of the benefits of the approach is that it provides a framework for future research and, most importantly, for establishing and testing alternative chronological models. We have examined whether or not the two Late Archaic period shell rings on St. Catherines are contemporary between 2430 and 2200 cal b.c. within this framework. Based on the available data we argue that they are most likely contemporary. This is a similar result to the summed probability approach used by Sanger and Thomas (2010), and adds strength to this hypothesis. However, the changes in material culture defined by Sanger and Thomas could have occurred in under a decade during the Late Archaic and more precise AMS 14C dates could provide additional insights into the cultural processes in play. We argue that these chronological improvements are best accomplished in an iterative fashion within the Bayesian statistical framework established in this chapter.

CHAPTER 3: INTERPRETING SEASONALITY FROM MODERN AND ARCHAEOLOGICAL FISHES ON THE GEORGIA COAST

Elizabeth J. Reitz, Bruce M. Saul, J.W. Moak, Gwendolyn D. Carroll, and Charles W. Lambert[14]

Estuarine fishes are a mixture of endemic, marine, and freshwater species attracted to estuaries as nursery grounds and feeding areas. The potential of estuaries to fill these roles varies seasonally, raising the possibility that fishes can serve as indicators or ecological groups that can be used to consider seasonal patterning in human fishing strategies. In this chapter, modern spatial and seasonal habits of fishes on the Georgia coast (USA) are used by analogy to assess seasonal fishing activities in the archaeological past. Despite problems common to all ecological analogies, we find that fishing was highly selective, that the most ubiquitous fish taxa in the archaeological record of the Georgia Bight are not markedly seasonal, and that the overall record is marked by stability rather than change. This limits the value of fish presence and ubiquity to provide information about seasonality in human behavior and changes in that behavior over time. Although settlement patterns should not be inferred uncritically from season of availability, the evidence that the fish taxa most ubiquitous in the archaeological record generally are available throughout the year within these estuaries raises doubts about the ability of unicausal economic, residential, and foraging models to capture the complexity of human life in such environments.

In his seminal review of seasonality studies, Gregory Monks (1981) critiques common methodologies used to study seasonality and offers a framework for integrating such studies. He argues that seasonality studies should begin by asking the question: seasonality of what? Monks identifies three major responses to this question: season of availability, season of activity, and season of location. He suggests that season of availability and season of activity are linked, but cautions against associating these with season of location, specifically season of site occupation and settlement patterns.

Despite Monks’s caution, it is likely that more seasonality studies have focused on season of location and seasonal components of political, economic, and other social institutions than on season of availability or activity. This leaves the impression that seasonal aspects of availability and activity are resolved, whereas it is more likely that fishing strategies in the past specifically targeted fish communities and populations available throughout the year, albeit vulnerable to a variety of techniques in different estuarine habitats. Questions of availability and activity are subtle and unlikely to be answered by examining fish population characteristics such as seasonal variations in population structure, abundance, biomass, diversity, dominance, distribution, or body size without collaborative evidence from other sources.

The first of Monks’s (1981) three aspects of seasonality, the availability of fishes, is the focus of this chapter. Our goal is to associate the niches and habitat preferences of modern fishes with those of high-ubiquity fishes present in the archaeological record to derive season of availability using modern data from St. Catherines Island and Cumberland Sound, located behind Cumberland Island (fig. 3.1). The modern data from these locations show a clear seasonal pattern in fish availability measured by the number of fish individuals (fig. 3.2). Thus, we approach the question of seasonality of fishing on the premise that fishing strategies were informed by seasonal migratory patterns though these may be difficult to interpret when viewed through the lens of the archaeological record. This leaves the season of activity and season of location unresolved, though we have some thoughts on those as well.

Monks (1981) reviews much of the direct and indirect evidence used to study seasonality. In his discussion of indirect evidence, he critiques the many cultural variables that circumscribe season, activity, and location (see also, Morales Muñiz, 1998). His review of these variables is thorough, and is not repeated here, other than to emphasize that the archaeological record is a cultural one. Likewise, many of the biases associated with archaeofaunal data from sites associated with aquatic ecosystems, especially coastal ones, are reviewed elsewhere (e.g., Erlandson, 2001; Butler and Campbell, 2004; Reitz and Wing, 2008; Broughton, 2010; Campbell and Butler, 2010) and these critiques are not repeated here. The complexity of seasonality in anthropogenic contexts extends far beyond basic, descriptive data.

This study relies on Harry Kenward and Allan Hall’s (1997: 665) definitions of indicator groups and taxa. Indicator or ecological groups are combinations of organisms defined taxonomically or by some other common element (e.g., habitat, seasonal preference). Kenward and Hall (1997: 665) define an indicator taxon as “one which reliably carries the implication of the occurrence of some event, activity, or ecological condition in the past” and an indicator group as “a natural grouping of organisms selected because it includes a range of stenotopic species which together encompass a wide spectrum of ecological conditions or human activities relevant to the aims of the study being carried out.” Indicator taxa, single species typical of, perhaps even restricted to, specific niches may not be as useful as indicator groups for studying environments or human behavior. Estuarine organisms with strong preferences for specific combinations of temperature, oxygen levels, water depths, or other characteristics are more informative than are eurytopic organisms with broad tolerances.

Monks advocates an integrated, multiproxy, regional approach, termed by Kenward and Hall (1997: 665) as indicator packages, which they define as “a collection of recordable data of any kind which, when occurring together, can be accepted as evidence of some past state or activity.” Indicator packages are far more useful than an indicator taxon or indicator groups, but such complex data are unavailable for the current study.

Interpretation of archaeological evidence relies on ecological and ethnographic analogy; both of which should be used with caution. Ecological analogy uses behaviors of organisms in response to critical environmental parameters that can be observed today to infer habitats and niches in the past. Ethnographic analogies accomplish a similar goal using recent, observable human activities to interpret former behaviors. Changes in the anthropogenic, biogeochemical, and hydrologic environments affect all aspects of the ecological and archaeological record, and, consequently, all analogies must be viewed skeptically.

Fig. 3.1. Location of sites mentioned in this study. Modern cities are indicated by blocks and archaeological sites by circles.

Fig. 3.2. Monthly total catch, North and South beaches.

ESTUARIES AND FISHES

Our focus is on the section of the southern U.S. coast of the Atlantic Ocean known as the Georgia Bight, a large embayment extending along the coast from Cape Fear, North Carolina, to Cape Canaveral, Florida (fig. 3.1; Hayes, 1994). A series of barrier or sea islands forms a boundary between the coastal waters of the Atlantic and lagoons (locally known as estuaries). The distance between a barrier island and the mainland can be as much as 7 km. Barrier islands share similar Pleistocene and Holocene histories, as well as archaeological, biological, and physiographic characteristics (Hoyt, 1967; Hoyt and Hails, 1967; Johnson et al., 1974: 11; Thomas et al., 1978; Oertel, 1979; Howard and Frey, 1985; Frey and Howard, 1986; Hayes, 1994; Thomas, 2008; Bishop, Rollins, and Thomas, 2011). Barrier islands are between 5 and 17 km long and 1 and 6 km wide (Hubbard, Oertel, and Nummedal, 1979). Island elevations generally are less than 7 m, though individual dunes may be higher (Johnson et al., 1974: 11). St. Catherines and Cumberland islands are two of the largest barrier islands in this area.

The central portion of the Georgia Bight, corresponding with the Georgia coast, is characterized by large, complex, highly productive estuaries. These semienclosed lagoons have access to the ocean through deep sounds that separate the barrier islands from each other. Fresh waters from large, perennial rivers draining the mainland mix with ocean water through tidal action, resulting in biogeochemical properties that are intermediate between salt water and fresh water and change during each tidal cycle (Odum and Barrett, 2005: 421). This coastline is considered a low-energy to moderate-energy, mesotidal system (Hubbard, Oertel, and Nummedal, 1979). Estuaries in this area have the lowest energy levels in the Georgia Bight due to shoreline alignment, wind direction, and the broad continental shelf (Johnson et al., 1974: 89; Frey and Howard, 1986). Wave height is less than 0.1 m, somewhat larger toward the northern and southern ends of the Bight (Hubbard, Oertel, and Nummedal, 1979). Inlets and marshes along the Georgia coast experience the greatest tidal ranges in the Georgia Bight because these back-barrier lagoons are larger and more complex than those in South Carolina or Florida (Hubbard, Oertel, and Nummedal, 1979). The average tidal range is 2 m with a range of 1 to 3 m in spring (Schelske and Odum, 1961; Hubbard, Oertel, and Nummedal, 1979; Howard and Frey, 1985). A spring high tide may produce a 50% increase over mean tide level (Frey and Howard, 1986). A neap tide is absent in some areas, particularly in high marshes adjacent to the mainland. Surface water temperature extremes occur in January and August. In the estuaries associated with Sapelo and St. Catherines Islands, water temperatures range from 8° to 32° C, with an average of 20° C (Dahlberg, 1972; Dahlberg, 1975: 7–8). The turbid inshore waters of the Georgia Bight are generally no more than 10 m deep.

A distinction is made between estuaries and coastal waters. Coastal waters are divided into inshore waters and offshore waters. Inshore waters extend eastward from the mouths of sounds and the sandy beaches of barrier islands (Johnson et al., 1974: 86). Beaches bordering the seaward sides of barrier islands extend east to ca. 1–2 m depths. On St. Catherines Island, the beach zone extends seaward as much as 1000 m from North Beach and as little as 100 m from South Beach (fig. 3.3). Temperatures range from 7° to 29° C and salinities range from 25 to 31 ppt except when floodwaters reduce salinity (Dahlberg, 1972; Dahlberg, 1975: 113).

Estuaries are characterized by mosaics of tidal creeks, sounds, salt marshes, and marsh islands. Estuaries are divided into major habitats by salinity, water depth, dissolved oxygen, temperature, turbidity, and bottom topography, as well as other biogeochemical and hydrological properties (Schelske and Odum, 1961; Dahlberg, 1972; Dahlberg, 1975: 4–11; DEIS, 1978: D-411; Frey and Howard, 1986). One of these habitats is the lower reach of each estuary, including the sounds that separate barrier islands from each other and provide access to the sea. These are the widest and deepest habitats. Waters are polyhaline; salinities range from 18 to 32 ppt and temperatures from 8° to 32° C (Dahlberg, 1972; Dahlberg, 1975: 113). The high marsh includes the salt marshes and creeks of the upper littoral zone. Salinity levels in high marsh range from 15 to 30 ppt (Dahlberg, 1975: 7). Middle and upper reaches of estuaries primarily are composed of narrow, shallow creeks and marshes with salinity ranges between 0.3 and 29 ppt and temperature ranges from 8° to 32° C (Dahlberg, 1972; DEIS, 1978: D-412). Salinity increases in oligohaline creeks with rising tides but is diluted by freshwater runoff and rainfall. Salinity ranges from 0 to 14 ppt and temperatures range from 4° to 32° C (Dahlberg, 1972; Dahlberg, 1975: 7, 114). Freshwater creeks and ponds lie beyond the tidal reach. These generally are on the mainland, though the barrier islands also have freshwater sources. The final two habitats are low-salinity and high-salinity tidal pools. Low-salinity pools receive more freshwater runoff and are flooded only during high tide, whereas high-salinity pools are flooded regularly by tides and rarely receive fresh water. Salinity ranges in these pools are 0 to 34 ppt and temperatures range from 7° to 32° C (Dahlberg, 1972). Some high-salinity pools are associated with beaches, filling at high tide and perhaps isolated from the ocean at low tide, trapping some fish within them.

Characteristics that underlie seasonal patterns in feeding, growth, and reproduction include water temperature, dissolved oxygen, turbidity, salinity, predation, nutrients, and similar biogeochemical and hydrological properties. Many are highly variable on daily, seasonal, and annual cycles and organisms that live in estuaries are adapted to significant and frequent changes in such properties. For example, when freshwater discharge from mainland rivers is reduced by droughts, high-salinity waters and associated organisms may be found as far as 40 km inland (Frey and Howard, 1986) and the reverse is true during freshwater floods. The lower reaches of estuaries, closer to the ocean, are more saline than the upper reaches and less subject to the coldest temperatures (Johnson et al., 1974: 86, 89; Dahlberg, 1975: 7). Variations associated with each tidal cycle approach seasonal and annual ranges (Dahlberg, 1972; DEIS, 1978).

These habitats serve as nurseries and feeding areas for endemic, marine, and freshwater species so that population structure, numbers of species and individuals, and the average size of fishes vary seasonally within fish communities (Dahlberg and Odum, 1970; Conover and Ross, 1982; Rogers, Targett, and Vansant, 1984; Levin et al., 2001). Young fishes are more flexible and better able to tolerate the wide variations in estuarine conditions than are adults, which may be able to use the estuary only for short periods of time. Many species are not permanent residents of estuaries; they spawn in the ocean or in fresh water and their young use estuaries as nursery grounds. Some species live offshore as adults and only use estuaries as feeding grounds. Very few spend their entire life cycle within an estuary. The function of estuaries as nurseries for the annual crop of juvenile fishes presents an important feeding opportunity to predators, though properties such as salinity and temperature discourage some potential predators from taking advantage of this opportunity. Young fishes also are protected from many diseases and parasites by the extremes presented within estuaries. The seasonal dynamics of these roles reinforce the premise that fishes can serve as proxies for seasonal patterning in human fishing strategies.

The use of salt marshes and nearshore zones by fishes is often dependent on spawning cycles (Conover and Ross, 1982). Nearshore areas along barrier island beaches are breeding grounds for small prey fishes, such as mummichogs (Fundulus heteroclitus), which then attract larger predators (Martin et al., 2004). Food species, such as bay anchovies (Anchoa mitchilli) and Atlantic menhadens (Brevoortia tyrannus), spawn either in winter or early spring months, replenishing the food supply for larger predatory fishes that move into estuaries during the warmer months (Reis and Dean, 1981; Conover and Ross, 1982; Fives, Warlen, and Hoss, 1986). One of Georgia’s important predatory species, both now and in the past, is the red drum (Sciaenops ocellatus), which exemplifies this behavior. Red drums spawn offshore, inshore, and in estuaries between mid-August and October, typically in areas with salinities above ca. 30 ppt (Lowerre-Barbieri et al., 2008). Lowerre-Barbieri et al. (2008) report that many red drums are associated with deeper pools instead of shallower shoreline areas. Juvenile red drums subsequently mature in estuarine and shallow nearshore waters while schools of adults move between inshore and offshore areas. Rogers, Targett, and Vansant (1984) report that numerous species use upper estuarine nursery areas near freshwater river discharges in the Ossabaw Sound estuary, at the northern end of Ossabaw Island. Other patterns may be related to river discharge, temperature, food availability, or depth (Rogers, Targett, and Vansant, 1984; Smith and Wenner, 1985; Jassby et al., 1995). St. Catherines is different from most barrier islands because it does not receive a significant influx of fresh water from a nearby large river, contrasting with such islands as Ossabaw, Sapelo, St. Simons, and Cumberland that receive inputs of fresh water from rivers such as the Ogeechee, Altamaha, and St. Marys (Oertel, 1979; Howard and Frey, 1985).

Fig. 3.3. Map of St. Catherines Island, showing North and South beaches. Key to sites: 1, Meeting House Field; 2, St. Catherines Shell Ring; 3, Santa Catalina de Guale mission and pueblo; 4, North Beach; 5, McQueen Shell Ring; 6, Back Creek Village; 7, South Beach.

BACKGROUND PREMISES

Modern data from both St. Catherines and Cumberland islands show clear seasonal patterns in the abundance of fish individuals, with different patterns for beaches compared to estuarine reaches that probably reflect the seasonal migrations of juvenile and adult fishes. Thus, we approach the question of seasonality and fishing based on the background premise that fishing strategies were informed by migratory patterns that define season of availability, though we cannot prove this empirically. Archaeological indicator groups, organisms with similar requirements, may provide evidence of temporal or spatial choices, or indicate a specific collection strategy.

The other background premise is that a basic fishing strategy was followed within the Georgia Bight and was a major aspect of economic life (see references in table 3.1). This strategy changed remarkably little over the millennia despite changes in Holocene climates and other aspects of biogeochemical and hydrological parameters. The fishes that form the core of this fishing strategy are present in most, if not all, archaeological collections. This indicator group of fishes generally dominates archaeological collections in terms of minimum number of individuals (MNI) and biomass. Fishes in this indicator group move within estuaries or between estuaries and offshore habitats in response to a suite of seasonal variables associated with reproduction and feeding. The presence of this indicator group in an archaeological deposit could be evidence that specific environmental parameters prevailed when, and where, these animals were captured.

Although we can define membership in this indicator group, and do so in this chapter, we do not know where the preferred fishing grounds were within each estuarine system when the archaeological site under study was occupied because of the ever-changing nature of the estuarine environment itself in response to changes in climate, sea level, sedimentation, spit formation, dune building, freshwater hydrology, and other geomorphic processes that affect biological processes (Blanton and Thomas, 2008; Bishop, Rollins, and Thomas, 2011; chap. 1, this volume).

TABLE 3.1: Summary of Archaeological Sites and Vertebrate Collections (1)

Sites

Location

Time period

Screen size (mm)

NISP

MNI

No. taxa

No. fish taxa

Back Creek Village, Mississippian (Irene) 9Li207

St. Catherines Island, GA

a.d. 1300–1580

3.18

14,881

449

53

27

Bourbon Field, Mississippian (Savannah) 9Mc71

Sapelo Island, GA

a.d. 1000–1350

6.35

15,331

563

35

19

Cathead Creek, Mississippian (Savannah) 9Mc360

Darien, GA

a.d. 1200–1500

0.5

2,248

84

34

16

Cathead Creek, Woodland (Swift Creek) 9Mc360

Darien, GA

a.d. 300–700

0.5

1,610

74

27

19

Fountain of Youth Park, Archaic 8SJ31

St. Augustine, FL

1450–500 b.c.

1.59

215

28

15

11

Fountain of Youth Park, Miss. (St. Johns IIc) 8SJ31

St. Augustine, FL

a.d. 1513–1565

1.59

14,891

218

36

27

Jacksonville Electric Authority, Miss. (Savannah) 8Du634, 8Du669

Duval Co., FL

a.d. 1000–1500

1.59

7,380

179

30

16

Kenan Field, Mississippian (Savannah) 9Mc67

Sapelo Island, GA

a.d. 1000–1500

6.35

0

397

44

15

Kings Bay Locality, Mississippian (Savannah) 9Cam171a, 9Cam177

Kings Bay Locality, GA

a.d. 1200–1500

1.59

36,667

903

57

26

Kings Bay Locality, Woodland (Swift Creek) 9Cam171a, 9Cam177

Kings Bay Locality, GA

a.d. 300–700

1.59

37,530

1,704

46

27

McQueen Shell Ring, Archaic 9Li1648

St. Catherines Island, GA

2300–1950 b.c.

3.18

43,240

1,153

58

36

Meeting House Field, Mississippian (Irene) 9Li21

St. Catherines Island, GA

a.d. 1300–1520

various

6,193

105

23

7

Mission Sta. Catalina de Guale (Historic) 9Li13

St. Catherines Island, GA

a.d. 17th century

various

43,206

204

54

16

Pueblo Sta. Catalina de Guale (Historic) 9Li8

St. Catherines Island, GA

a.d. 17th century

various

14,493

167

50

14

Ribault Clubhouse, Archaic 8Du76

Duval Co., FL

2000 b.c.

3.18

2,885

144

37

26

St. Catherines Shell Ring, Archaic 9Li231

St. Catherines Island, GA

2540–2030 b.c.

3.18

49,587

1,249

69

31

St. Simons Cannon’s Point (Marsh) Ring, Archaic 9Gn57

St. Simons Island, GA

2240–1815 b.c.

3.18

19,970

345

45

25

St. Simons West Ring, Archaic 9Gn76

St. Simons Island, GA

2320–1970 b.c.

3.18

9,453

251

31

16

Sapelo Shell Ring III, Unit 9, Archaic 9Mc23

Sapelo Island, GA

2332–1740 b.c.

1.59

12,132

182

27

21

(1) NISP refers to number of identified specimens (vertebrates only). MNI refers to minimum number of individuals (vertebrates only); “No. taxa” refers to the total number of vertebrate taxa each collection; and “No. fish taxa” is the number of fish taxa in each collection. Data are from the following sources: Bourbon Field (Crook, 1978, 1984; Reitz, 1982); Cathead Creek site (Reitz and Quitmyer, 1988; Quitmyer and Reitz, 2006); Fountain of Youth site (Reitz, 1991); Jacksonville Electric Authority site (Lee et al., 1984; Reitz, Quitmyer, and Marrinan, 2009); Kenan Field (Crook, 1978); Kings Bay Locality (Reitz and Quitmyer, 1988; Quitmyer and Reitz, 2006); McQueen Shell Ring (Colaninno, 2010: 153–155; Sanger and Thomas, 2010); Meeting House Field (Reitz and Dukes, 2008); Back Creek Village (Bergh, this volume); Mission (Eastern Plaza Complex) Santa Catalina de Guale (Reitz et al., 2010); Pueblo Santa Catalina de Guale (Reitz et al., 2010); Ribault Clubhouse (Quitmyer and LeFebvre, 2004; Reitz, Quitmyer, and Marrinan, 2009); St. Catherines Shell Ring (Colaninno, 2010: 116–119; Sanger and Thomas, 2010); St. Simons Cannon’s Point (Marsh) and West Rings (Marrinan, 1975; Reitz, Quitmyer, and Marrinan, 2009; Colaninno, 2010: 95–97, 100–101; Marrinan, 2010); and Sapelo Shell Ring (Thompson, 2006; Colaninno, 2010: 104–105). Descriptions of each site, the methods used during excavation, and the original zooarchaeological studies of each collection are found in the above sources. All of these materials were identified using the comparative skeletal collections at the Florida Museum of Natural History and the Georgia Museum of Natural History. Swift Creek is a Woodland period; Savannah, Irene, and St. Johns IIc are Mississippian periods. Human MNI estimates are excluded.

METHODS

Modern fish samples from St. Catherines Island are from collection sites on the North and South beaches (fig. 3.3). These beaches lie on the exposed seaward side of the island. The samples were taken between 1998 and 2009. Sites were selected to provide representative samples from the entire maximum accessible area and to incorporate as many differences in bottom topography as possible. Initially four sites were selected on each beach. One site on North Beach was eliminated and another was occasionally inaccessible due to shifting mud, snags, and oyster beds, phenomena that undoubtedly have always influenced fishing in this and other coastal areas. Each site was sampled on a monthly basis during the three-hour period before low tide, allowing for collection in morning, midday, evening, night, and predawn periods. Samples were collected under all weather conditions, excluding lightning storms, extreme cold, and rough surf, which would endanger the health and safety of the research team or make sampling impractical.

Species composition was assessed at each site by towing seines in a standard quarter-haul fashion from the beach. Two hauls were made using a 30.5 m monofilament seine, with a 2.5 cm mesh, and two hauls were made with an 18.3 m cotton mesh bag seine of 0.3 cm mesh (Hillman, Davis, and Wennemer, 1977). Each tow was offset 9 to 18 m from the previous one to reduce the effects of population disbursement associated with the previous pull.

The 0.3 cm mesh net used in the bag seine was designed to collect all sizes of all possible game and nongame species. Differences in nets in the modern St. Catherines Island study likely do not pose a bias in this study. The 0.3 cm mesh used in the modern study captured all but the very smallest juvenile fishes. Zooarchaeological collections, of course, only contain skeletal elements and not live, whole fish; thus archaeological excavations must use a smaller screen size to recover the remains of the same small taxa that can be captured live using a larger mesh. For example, the largest, intact, skeletal element of a mummichog with a total length of 86 mm is 12.5 mm. As a live fish, this mummichog would be captured in the bag seine used in the modern study.

The fishes in each haul were identified, enumerated, and measured. Larger specimens, particularly if part of a breeding cohort, were measured first and returned to the water to reduce sampling mortality rates. Measurements were taken using a Wildco fish measuring board with 1.0 cm divisions (Wildlife Supply Company, Yulee, FL). Specimens that could not be identified in the field were taken to the lab and preserved in a 10% formalin solution. Fishes were identified to species using marine field guides (Breder, 1929; Dahlberg, 1975; Robins et al., 1986; Hoese and Moore, 1998). A representative sample of all sizes was measured when a large number of specimens of a single species were collected (≥ 25) and the remaining specimens were counted.

The following discussion generally focuses on data from South Beach because, thus far, relatively few archaeological sites have been found in the North Beach area (Thomas, 2008: 546). Most of the archaeological sites on the eastern side of the island are closer to South Beach, though very few sites are actually adjacent to either North or South Beach.

Because South Beach data are from a seaward beach, they are supplemented with data from Cumberland Sound, a complex back-barrier system landward of Cumberland Island, for which similar quantified modern data are available (figs. 3.1, 3.4). This enables us to assess seasonal pulses in the shallow waters behind a barrier island (DEIS, 1978). Fishes were collected quarterly at four stations along each transect using a 5 m semiballoon otter trawl and at shallow water stations (A, C, X, D, E, F, G, I, J, K, L, M, N) using a 50 ft bag seine. Migratory fish collections were made in winter and spring quarters using three 100 ft gill nets with ¾ in., 1½ in., and 3 in. meshes set near transects D and E for a complete tidal cycle (DEIS, 1978: D-192). The methods used in the Cumberland Sound study are described in more detail in the Draft Environmental Impact Statement for Cumberland Sound (DEIS, 1978: 186, 192–193). Occasionally, specific reference is made to biological sampling stations D and E, located in that part of the sound known as Kings Bay.

Differences in sampling location and sampling gear for the modern St. Catherines Island and Cumberland Sound collections limit our ability to directly compare modern data from these two locations. The modern collection strategies were not designed to replicate each other or human behavior in the past. The St. Catherines Island modern data are from a collection locality that may not have been frequently used by islanders (seaward beaches), but the collection gear (manual seines) is probably similar to what was used in the past. The Cumberland Sound data represent a collection locality similar to that used by people living in this region (back bay waters and tidal creeks), but using a modern collection gear (mechanized trawls) unknown until recently. From an archaeological perspective, it would be highly desirable to collect modern samples from archaeologically probable collection localities using probable collection gear.

The archaeological collections are from 19 sites or temporal components of multicomponent sites between St. Catherines Island and Anastasia Island, Florida (table 3.1; fig. 3.1). Five of these sites (McQueen Shell Ring, Back Creek Village, Bourbon Field, St. Simons Cannon’s Point [Marsh] Ring, and St. Simons West Ring) are from the seaward side of barrier islands. The Bourbon Field and the St. Simons Island sites are protected from the ocean by additional, smaller, barrier islands (Blackbeard and Little St. Simons islands) and two St. Catherines Island sites are adjacent to an inlet (McQueen) and a marsh (Back Creek Village) on the seaward side of the island. Other barrier island sites (St. Catherines Shell Ring, Meeting House Field, Mission and Pueblo Santa Catalina de Guale, Sapelo Ring III, and Kenan Field) are located on the landward sides of barrier islands. The remaining sites are mainland sites (Cathead Creek, Kings Bay, Ribault, Jacksonville Electric Authority, and Fountain of Youth). Archaeological collections were deposited between ca. 2560 b.c. and a.d. 1680. In the case of sites occupied prior to the onset of the First Spanish period (a.d. 1565), it is not known if any were contemporaneous or what relationships among each site’s occupants might have occurred. Establishing contemporaneity is clearly required to link seasonality in the resource base with residential patterns (see Kennett and Culleton, chap. 2, this volume).

Monks (1981) identifies presence-absence of seasonally available species as the simplest, oldest, and most common methodology and this is one of the methods used in the archaeological part of this study. Presence-absence relies upon ecological analogy, using the seasonal habits of fishes today to infer seasonal behaviors in the past. Fishes are expected to move within estuaries or between estuaries and either freshwater or offshore habitats in response to a suite of seasonally sensitive variables associated with reproduction and feeding. The presence of a fish in an archaeological deposit could be evidence that a specific suite of parameters prevailed when, and where, the animal was captured. The absence of any resource, or the absence of evidence that a resource was used during a specific season, as we all know, is more problematic (e.g., Balasse et al., 2003). To emphasize this point, we refer only to “presence” henceforth, using presence of taxa as reported in zooarchaeological reports (table 3.1). We focus on those fishes that form our hypothesized core group in the Georgia Bight fishing strategy (Quitmyer and Reitz, 2006; Reitz, Quitmyer, and Marrinan, 2009; Reitz et al., 2010). Variables that affect presence will be revisited below.

An ideal study would combine presence with information about fish size and other indicators of age, such as increments. The tidal and seasonal movement of fishes within estuaries and between estuarine and coastal waters is closely associated with age and body size. Age cohorts are seasonal markers in fishes because habitats and niches change as individuals grow larger and reach reproductive size. Members of an age cohort of a given species not only are roughly the same size at the same time, they also occupy similar habitats and niches at the same time, and are susceptible to capture with similar fishing gear. As their size changes with maturity, so too do the habitats and niches of the fishes, and the fishing strategy likely to efficiently capture them. These variables are likely to be somewhat different among those members of a taxon that occupy ideal habitats and those that occupy the slightly less optimal edges of the species biogeographical range. Sadly, too few measurements of archaeological fish remains, or associations of size with age, are available for the Georgia Bight to use in this study. Morphometric and incremental studies should become routine in all future archaeological projects.

Both the modern South Beach and the archaeological fishes are examined using ubiquity analysis and Shannon-Weaver diversity indices. Ubiquity analysis of modern fishes involves dividing the number of samples in which an individual fish species is present by the total number of samples. Ubiquity analysis of archaeological data involves dividing the number of archaeological collections in which a specific fish taxon is present by the total number of archaeological collections in this application (N = 19). Only those taxa for which MNI is estimated are used in the archaeological ubiquity analysis. This approach controls for the diverse attribution levels in the archaeological species lists and is similar to the ubiquity analysis of modern collections, which is based on individual fishes.

The Shannon-Weaver diversity index is estimated for each modern and archaeological site using the following function: H’ = –Σ Pi log Pi, where Pi is the proportion of individuals in the i-th species (Dahlberg and Odum, 1970). Shannon-Weaver is also estimated for the combined archaeological assemblage by adding the indices for all of the archaeological collections in table 3.1 together and dividing by the total number of collections (N = 18), excluding Kenan Field for which MNI is unavailable. Shannon-Weaver allows us to compare proportions and not numbers, accommodating characteristics in the data and differences in techniques (see Reitz and Wing [2008: 110–113] for a review of this method). A t-test compares the overall archaeological diversity and modern diversity. Analysis of variance (ANOVA) compares seasonal differences of modern data and archaeological collections.

Fig. 3.4. Aquatic biological sampling stations in Cumberland Sound (modified from DEIS, 1978: D-187).

Caveats

It bears repeating that comparisons of modern and archaeological data rely on the premise that relationships exist among the organisms studied, their environmental preferences, environmental conditions at the site, and human behavior. This premise underlies the use of ecological analogies to infer relationships in the past and is basic to studies that associate season of availability with other aspects of human behavior. In the Georgia Bight, long-term processes operate within an ecosystem in which populations and communities accommodate daily variations during each tidal cycle. Coastal landscapes are highly dynamic, which means that environmental proxies and ecological analogies must be used cautiously.

Many analogies assume that organisms have not changed their habitats and niches during the intervening centuries, a premise that is unlikely to be true (e.g., (Webb, Hedges, and Robinson, 1998). In the case of St. Catherines Island, geological and climatological processes have altered the structure and function of aquatic and terrestrial environments (Blanton and Thomas, 2008; Bishop et al., 2011; Rich, Vega, and Vento, 2011). Many nonanthropogenic phenomena are associated with environmental change, such as floods, storms, plant successions and other ecosystem processes, coastal remodeling, and climatic cycles. These have both short- and long-term outcomes. Routine ecological processes (e.g., competition, predation, community transformations) alter the composition and physical location of populations and communities. All of these processes can occur without human intervention; but it is likely that the structure and productivity of estuaries in the Georgia Bight have been impacted by human fishing strategies for millennia (Reitz, 2004).

Thus, the suite of estuarine organisms found at a specific time and place may change, either for a long time or a short time, sometimes within a matter of hours. Organisms previously common in a specific fishing ground may now be rare and taxa formerly absent from a location may now be abundant there. In reference to the present study, however, it is important to recognize that we may not know what the landscape at the time of occupation was or which specific habitats were exploited from a specific site at a given point in time. This, of course, is the conundrum faced by all diachronic and synchronic studies of seasonal behaviors, ecosystems, and environments.

Biological surveys typically define seasons by the lunar calendar: January–March, April–June, July–September, and October–December. Many characteristics are associated with seasons beyond the lunar calendar and these vary within a range from one year to the next. It is likely that storms, climate cycles, and other dynamics influenced cultural and ecological systems at several organizational, spatial, and temporal scales during the millennia encompassed in this review (Redman, Grove, and Kuby, 2004; Reitz, Quitmyer, and Marrinan, 2009). Fishing strategies, residential patterns, and behaviors of fishes themselves undoubtedly responded to these changes but might not occur precisely during the winter, spring, summer, and fall months defined by the Gregorian calendar.

This diachronic ambiguity is compounded by synchronic Holocene changes in sea levels, sedimentation, distance from fluvial sources, shoreline configurations, littoral drift, aeolian sand accumulations, migrations of tidal inlets, storm-related topographic changes, biogeochemical properties, and sea surface temperatures, among other changes (Dolan, Hayden, and Lins, 1980; Liu, 2004; Reitz, Quitmyer, and Marrinan, 2009; Bishop, Rollins, and Thomas, 2011). The broad general similarities among fish populations and communities in both modern and archaeological collections suggest that fish taxa represented in today’s estuaries were able to endure synchronic changes just as they are able to endure diachronic ones. Certainly, however, ecosystem structures and processes were impacted by synchronic changes, which are variables in this record of seasonal patterning; one of many reasons why it is difficult to associate seasonal aspects of resource availability with human behavior in the past using ecological analogies.

The present study is only possible if one presumes that the overall estuarine characteristics required by aquatic animals were met someplace within the environment, though the exact physical and morphological aspects with regards to the archaeological sites investigated are unknown. At the risk of a circular argument, while we cannot define the temperature/salinity regime that prevailed at a specific time and place, or specify where inlets, tidal creeks, sounds, salt marshes, marsh islands, and shallow waters were, the suite of fishes recovered from St. Catherines Island shows remarkable richness as well as continuity. The dominant fish taxa, those in the indicator group of fishes, are specifically those known for behavioral flexibility, a characteristic necessary for all organic life in the Georgia Bight, including people.

Fish biologists identify most of their catch to species and zooarchaeologists rarely do. It is species that respond to daily, seasonal, and annual variations, not genera or families; but species-level identifications often elude zooarchaeological studies. Thus, we may know we have a sea catfish (Ariidae) in an archaeological collection, but not which of two possible sea catfish species (Ariopsis felis, Bagre marinus). Much more information is available about the habitat preferences of the hardhead catfish (A. felis), for example, than for the family Ariidae. Likewise, mullet (Mugil spp.) specimens in archaeological collections almost always are attributed only to the genus Mugil because it is difficult, if not impossible, to distinguish between striped mullets (M. cephalus) and white mullets (M. curema). It is equally difficult to distinguish between the two species of mullets in modern, live-collected fishes, many of which are present in the modern South Beach collection.

Recovery method is a well-known source of bias in archaeological analyses. Four of the 10 fishes with ubiquity above 0.44 in the modern South Beach collection are small-bodied taxa, defined as having an adult total length of less than ca. 250 mm today (Reitz, Quitmyer, and Marrinan, 2009; Reitz et al., 2010: 234–237). Large-bodied taxa are ones with an adult total length over 250 mm. The mean total length (TL) of inland silversides (Menidia beryllina) is 79 mm, bay anchovies 54 mm, striped killifishes (Fundulus majalis) 62 mm, and striped anchovies (A. hepsetus) 73 mm in the modern St. Catherines Island collection (table 3.2; Augusta State University field notes; see also, Jorgenson and Miller, 1968). It is unlikely that these four taxa would be represented in an archaeological collection if a screen size of more than 3 mm was used during archaeological fieldwork. Many of the archaeological collections were recovered using mesh sizes too large to catch the small bones of these small-bodied taxa. For this reason, and because of the susceptibility of small fish elements to site formation processes, it is possible, if not probable, that very small taxa, as well as small individuals of large-bodied taxa, are underrepresented in the archaeological record. Without measurements and body size estimates for all fishes in all of the archaeological collections merged in this study, it is not possible to know which specific archaeological individuals were large or small, unless the specimen is from a biologically small fish taxon.

Another limitation of all fishery studies is the question about how people used small fishes, if they did. Today, we eat anchovies and other small fishes, bones and all, and it is possible that people did so in the past. Very small fishes, however, could have been used as bait instead of food. We question whether bait fish would be present at an archaeological site; it is more likely that bait was used shortly after capture, or tossed into the water at the end of the fishing expedition. Additionally, as this and other contributions in this volume demonstrate, small-bodied fishes can be prominent components of archaeological collections from the Georgia Bight, too prominent to be dismissed as gut contents of predators, given that many of these presumed predators are themselves rare or absent in the archaeological record. Regardless of whether or how small fishes were used, the season of availability would be informative of human behavior.

Differences between modern seines and devices used in the past are highly important sources of bias. Such differences grow in significance when one recognizes that gear is tailored to prey, with specific gear used for specific purposes. Gear differences are particularly profound when modern trawl data, taken from sounds, are used to interpret archaeological fishing strategies. Anticipating the results of this study, there is no evidence that offshore habitats or deep inshore sounds were used in the past. Net size does influence catch, but nets used in the modern St. Catherines collection, at least, were selected purposefully to catch a large variety of species of all sizes. The merit of the St. Catherines modern study is that seines were used to sample two localities whose parameters are similar to some of those probably used in the past: near-shore shallow waters into which students could safely wade. The Cumberland Sound data are less than ideal in this regard.

Ideally, modern fishes would be collected using gear more similar to that surmised for the past in locations likely to have been routinely used in the past. Early societies would have used multiple methods of capture to maximize their efforts, probably in shallow waters. Experiments that test the seasonal quantity and variety of fishes that might be captured using fishing gear and locations hypothesized to have been used in the past would greatly improve our understanding of many aspects of this study. Arguments that infer archaeological fishing strategies in the archaeological past using modern fishing strategies are, by their nature, circular. This issue plagues all ecological and ethnographic analogies.

There are no obvious solutions to any of these caveats; but it is in recognition of these issues that statistical tests of significance are avoided; they would confer on the results of this study an aura of legitimacy that is unwarranted. Clearly, well-designed, regional, multiproxy studies designed to contribute to definitions of indicator packages would make substantial contributions to resolving some of the problems with ecological analogies encountered in this study; but it is likely that most cannot be resolved without a time machine. Having acknowledged this, however, it is clear from the data in this volume and in other volumes in the American Museum of Natural History series on St. Catherines Island that we do know a great deal about life on this island and in the Georgia Bight.

TABLE 3.2: Seasonal Total Length (TL) Ranges (in mm) for high-ubiquity taxa from South Beach

Winter

Spring

Summer

Fall

Common name

Scientific name

Min

Mean

Max

N

Min

Mean

Max

N

Min

Mean

Max

N

Min

Mean

Max

N

Inland silverside

Menidia beryllina

6

82

122

2151

10

90

121

3327

6

71

121

1699

32

73

102

1246

Bay anchovy

Anchoa mitchelli

40

58

85

1543

15

62

520

2384

24

48

480

2878

20

50

83

1860

Southern

kingfish

Menticirrhus americanus

30

101

365

223

20

106

372

220

1

65

520

1776

19

68

370

544

Striped mullet

Mugil cephalus

22

99

446

275

19

121

452

67

19

127

362

829

29

166

455

778

Striped killifish

Fundulus majalis

39

57

81

56

44

70

135

188

20

59

113

870

34

61

95

100

Florida pompano

Trachinotus carolinus

41

74

254

55

14

35

227

466

10

75

245

3954

15

63

419

1222

Silver perch

Bairdiella chrysoura

116

143

232

113

45

148

270

203

129

160

199

18

112

143

195

84

Star drum

Stellifer

lanceolatus

21

43

97

49

19

47

160

42

19

78

440

420

26

105

167

22

Striped anchovy

Anchoa hepsetus

59

89

120

18

43

63

118

347

26

60

122

443

32

81

116

137

Hardhead catfish

Ariopsis felis

292

292

292

1

226

331

421

69

42

130

550

345

280

333

384

11

Spot

Leiostomus

xanthurus

82

188

271

9

60

100

182

16

70

154

231

49

115

208

262

32

Atlantic bumper

Chloroscombrus chrysurus

0

0

0

0

78

97

111

13

8

63

162

621

32

69

147

480

Red drum

Sciaenops

ocellatus

370

509

723

33

405

507

640

14

20

367

535

15

350

508

680

15

Atlantic

menhaden

Brevoortia

tyrannus

114

179

235

24

125

164

443

11

61

134

212

150

142

177

283

40

Gulf kingfish

Menticirrhus

littoralis

64

254

467

40

29

199

370

21

62

152

262

18

60

255

411

13

Atlantic

needlefish

Strongylura marina

275

402

470

7

127

359

445

8

212

302

423

22

260

394

495

40

Bluefish

Pomatomus saltatrix

29

73

160

3

18

61

345

95

35

150

280

20

34

172

257

3

RESULTS

Modern South Beach and Cumberland Sound Data

A total of 134,895 individual fish representing 102 species were collected from North and South beaches between 1998 and 2007 (N = 208; table 3.3). A total of 79 species were collected from North Beach and 66 species were collected from South Beach. In terms of catch composition, 10 species are present in over 95% of the total catch and 75% of the total number of fishes caught consists of four species: bay anchovies, inland silversides, striped mullets, and Florida pompanos (Trachinotus carolinus). Mean catch per unit effort (CPUE), a measure of the number of fishes caught per seine haul, was slightly higher for South Beach than for North Beach (table 3.4). With respect to gear, 121,425 fish were caught with the bag seine and 13,470 were caught with the monofilament seine. The average total length (TL) of fish caught with the bag and monofilament seines was 68 mm and 132 mm, respectively. No fish had a ubiquity of 1.0 (i.e., was present in every sample) in the combined North Beach and South Beach data (table 3.5). Inland silversides and bay anchovies have the highest ubiquity in the combined data, followed closely by southern kingfishes (Menticirrhus americanus) and striped mullets. The number of fish individuals is lowest in the colder months and highest in warm months (fig. 3.2). A large pulse is clearly visible from April to September, followed by a decline in October. The average size of fishes is another aspect of population structure related to seasonality (table 3.2).

Inland silversides and bay anchovies also have the highest ubiquity in the South Beach collection, followed closely by southern kingfishes and striped mullets (table 3.6). The ubiquity of fishes collected per quarter from South Beach has a distinctly seasonal pattern (table 3.7). Average ubiquity is highest in summer, followed by fall, spring, and winter. Species diversity on South Beach is highest in the spring collection and lowest in the fall collection (fig. 3.5). Summer and winter are the only seasons that show significantly different diversity in the modern data (table 3.8).

Cumberland Sound data represent fish seasonality in a back-barrier location. The stations near Kings Bay are the most productive areas in terms of fish abundance and biomass (fig. 3.6; DEIS, 1978: D-436, D-448–451, D-456). This may reflect the abundance of food and other nursery characteristics in these shallow waters.

Cumberland data show seasonal pulses in the number of fish individuals as fishes in different parts of their life cycles migrate in and out of the sound (fig. 3.7; DEIS, 1978: D-437, D-448–451). Large numbers of fish are uniformly distributed during summer and fall though they concentrate in shallow waters near shore in the summer and in midchannel locations in the fall. In winter, fish are more abundant in the warmest, deepest parts of the estuary. Many of the species present in winter are year-round residents, but other taxa leave the estuary altogether. In spring, fish abundance is greatest near freshwater creeks. The number of fishes present in the estuary, however, is lowest during the colder months.

This does not convey the complexity of fish behavior because habitat preferences change as individuals mature. Members of each age cohort have distinct habitat and niche preferences, which change as animals mature during the annual cycle. Most juveniles are more tolerant of estuarine conditions than are most adults, which prefer more stable offshore waters. Larger, more mature fishes are present in fall collections, and dominate winter ones, because juveniles have left to mature elsewhere. Spring collections contain young of the year, in addition to larger individuals. The annual influx of juveniles reduces the average weight per fish in each sample. Juveniles grow larger as they mature, thereby increasing the average weight per individual. Thus, the average weight per fish is highest in winter samples, declines in spring and summer samples, and is lowest in fall samples (DEIS, 1978: D-480–481).

The spawning cycle and use of Cumberland Sound by juvenile fishes are reflected in changes in the average weight of fishes (biomass) during the year at specific locations (fig. 3.8; DEIS, 1978: D-458, D-474–475, D-477–478). Changes in biomass have a general association with the seasonal movement of adult and juvenile fishes in and out of the estuary. During summer, fish biomass is distributed throughout the estuary, but concentrated at the mouth of the estuary and near the confluence of two freshwater rivers. In fall the greatest concentration of biomass is in and near Kings Bay, which is also where penaeid shrimp are abundant. The concentration of fish biomass around Kings Bay also reflects the influx of juvenile fishes into this shallow part of the estuary.

Community structure in the summer and fall is essentially the same, but somewhat different from that in spring and very different from that in winter (DEIS, 1978: D-492; see also, Dahlberg and Odum, 1970). Larger fishes, more mature ones, are present in fall (DEIS, 1978: D-523). Larger fishes are much more common in winter, when small juveniles have left the area to mature elsewhere. In spring, larger fishes are joined by small individuals, probably young of the year. The annual influx of juveniles reduces the average weight per fish; as these mature and grow larger the average weight increases. Thus, the average weight of individual fish is highest in winter (10.9 g/fish), declines in spring (4.7 g/fish) and summer (3.5 g/fish), and is lowest in fall (2.8 g/fish). Many of the species present in winter are year-round residents (DEIS, 1978: D-483).

Diversity has a seasonal pattern as fishes respond to spawning cycle, salinity, water depth, and water temperature (fig. 3.9; DEIS, 1978: D-484–489). Although the nursery aspects of the estuary are complex, there is a relationship between diversity and the spawning cycle. Young fishes enter estuaries for the nursery aspects, adults enter to feed and spawn, and both adult and newly mature fishes leave for inshore and offshore waters. During summer and fall, the highest diversities are found in areas with the lowest salinity values. This does not hold true for winter, when water temperatures decline and fishes move from shallower waters into deeper, warmer areas. In spring, both low and high salinity areas have high species diversity, though estuarine waters may be too cool for some species, which remain offshore in warmer waters.

Modern data from South Beach and Cumberland Sound have different patterns of seasonal abundance (figs. 3.2, 3.7). Although these differences could be the result of different modern catch technologies used in the South Beach and Cumberland Sound studies, they also can be explained by differences in habitat sampled. It is likely that the more exposed, higher-salinity South Beach location represents a portion of life cycles of high-ubiquity fishes that is less common in Cumberland Sound. This difference may reflect the seasonal migration of fishes into and out of the back-barrier reaches lying between sea islands and the mainland as part of their growth and reproduction cycles. Star drums (Stellifer lanceolatus) are most abundant in the South Beach catch in the summer (fig. 3.10A), but they are most abundant in the Cumberland Sound catch in the fall (fig. 3.10B; DEIS, 1978: D-438–447, D-459–473), for example. We use star drums in this example because they constitute 27% of fishes individuals captured in Cumberland Sound and 15% of the biomass in Cumberland Sound. They are the most abundant species in Dahlberg and Odum’s (1970) study of Sapelo and St. Catherines sounds and have an archaeological ubiquity of 0.84. This is always a small-bodied fish (TL range 7.5–102.5 mm) despite indeterminate growth (table 3.2; Dahlberg and Odum, 1970).

Dahlberg and Odum (1970) elaborate upon the seasonal aspect of fishes in the back-barrier areas. They report that 29 of the 70 fish species “were collected at estuarine stations in all seasons or at least in both winter and summer” (Dahlberg and Odum, 1970: 384). Only eight of the 20 species were restricted to the colder months and seven species were collected only in warmer months. Seasonal trends are most pronounced in the sounds and least in the upper marsh creeks (Dahlberg and Odum, 1970). Dahlberg and Odum (1970) do not report significant differences in diversity of fishes in sounds and tidal creeks behind St. Catherines Island, however. They did not specifically sample habitats for the smaller fish species (e.g., silversides, mummichogs, and mullets), or sample the seaward beach on the island.

Well-versed anglers understand these changes in fish behavior, as well as the accompanying variations in potential capture rates. Today, fishing strategies take advantage of local knowledge of seasonal patterns, derived from decades of experience, oral traditions passed down through generations, and experts such as boat captains, guides, and recreational fishermen (Murray, Neis, and Johnsen, 2006). These insights are used for subsistence, economic gain, and recreation (Matthews, 1928; McClanahan and Cinner, 2008). Such local knowledge undoubtedly informed earlier fishing strategies in the Georgia Bight and can be used to develop current and historical conservation management plans (Murray, Neis, and Johnsen, 2006; Silvano et al., 2006; McClanahan and Cinner, 2008).

Fig. 3.5. Comparison of archaeological and South Beach fish diversity.

Fig. 3.6. Abundance and biomass values for Cumberland Sound (DEIS, 1978: D-456). Upper reaches include data from stations A, B, and C; Kings Bay includes data from stations X, D, E, and F; lower reaches include data from stations G, K, N, and O; ocean includes data from stations P, Q, R, and S; shown on fig. 3.4. Data from DEIS (1978: D-456).

Fig. 3.7. Overall abundance for Cumberland Sound (DEIS, 1978: D-437).

Fig. 3.8. Seasonal percentages of fish biomass at Stations D and E, Cumberland Sound (DEIS, 1978: D-458).

Fig. 3.9. Seasonal variations in fish diversity at Stations D and E, Cumberland Sound (DEIS, 1978: D-489).

Fig. 3.10. Abundance of star drum (Stellifer lanceolatus) individuals per season: (A) South Beach and (B) Cumberland Sound collections. Cumberland Sound data from DEIS (1978: D-439, D-441, D-443, D-445).

TABLE 3.3: Total Catch by Year for North Beach and South Beach (N = 208)

Year

North (N = 107)

South (N= 101)

Total

1998

4,126

12,587

16,713

1999

9,088

9,423

18,511

2000

6,093

16,571

22,664

2001

5,392

10,783

16,175

2002

2,506

2,912

5,418

2003

2,484

1,865

4,349

2004

3,367

9,265

12,632

2005

5,954

9,696

15,650

2006

6,539

6,554

13,093

2007

6,609

3,081

9,690

Total

52,158

82,737

134,895

TABLE 3.4: Mean Catch per Unit Effort (CPUE) by Year for North Beach and South Beach

Year

North (N = 1196)

South (N = 1554)

Average

1998

32.5

71.5

55.2

1999

64.5

54.5

59.0

2000

41.2

104.2

73.8

2001

37.4

56.5

48.3

2002

27.2

27.0

27.1

2003

32.3

16.1

22.5

2004

25.9

48.3

39.2

2005

46.9

55.1

51.7

2006

49.9

42.0

45.6

2007

83.7

28.8

52.1

Average

44.1

50.4

47.4

TABLE 3.5: Fishes with Ubiquity ≥ 0.25, North Beach and South Beach Data Combined

Family

Common name

Scientific name

Ubiquity (N = 101)

Atherinopsidae

Inland silverside

Menidia beryllina

0.98

Engraulidae

Bay anchovy

Anchoa mitchelli

0.93

Sciaenidae

Southern kingfish

Menticirrhus americanus

0.89

Mugilidae

Striped mullet

Mugil cephalus

0.85

Fundulidae

Striped killifish

Fundulus majalis

0.71

Carangidae

Florida pompano

Trachinotus carolinus

0.67

Sciaenidae

Silver perch

Bairdiella chrysoura

0.51

Sciaenidae

Star drum

Stellifer lanceolatus

0.49

Engraulidae

Striped anchovy

Anchoa hepsetus

0.44

Ariidae

Hardhead catfish

Ariopsis felis

0.36

Sciaenidae

Spot

Leiostomus xanthurus

0.36

Carangidae

Atlantic bumper

Chloroscombrus chrysurus

0.32

Sciaenidae

Red drum

Sciaenops ocellatus

0.30

Clupeidae

Atlantic menhaden

Brevoortia tyrannus

0.29

Sciaenidae

Gulf kingfish

Menticirrhus littoralis

0.28

Belonidae

Atlantic needlefish

Strongylura marina

0.26

Pomatomidae

Bluefish

Pomatomus saltatrix

0.25

TABLE 3.6: Fishes Collected from South Beach with Ubiquity ≥ 0.25

Family

Common name

Scientific name

Ubiquity (N = 101)

Atherinopsidae

Inland silverside

Menidia beryllina

0.96

Engraulidae

Bay anchovy

Anchoa mitchelli

0.91

Sciaenidae

Southern kingfish

Menticirrhus americanus

0.89

Mugilidae

Striped mullet

Mugil cephalus

0.81

Fundulidae

Striped killifish

Fundulus majalis

0.72

Carangidae

Florida pompano

Trachinotus carolinus

0.67

Sciaenidae

Red drum

Scianops ocellatus

0.44

Engraulidae

Striped anchovy

Anchoa hepsetus

0.43

Sciaenidae

Silver perch

Bairdiella chrysoura

0.41

Carangidae

Atlantic bumper

Chloroscombrus chrysurus

0.33

Ariidae

Hardhead catfish

Ariopsis felis

0.31

Sciaenidae

Spot

Leiostomus xanthurus

0.30

Sciaenidae

Star drum

Stellifer lanceolatus

0.30

Sciaenidae

Gulf kingfish

Menticirrhus littoralis

0.29

Pomatomidae

Bluefish

Pomatomus saltatrix

0.25

TABLE 3.7: Seasonal Ubiquity of Fishes Collected from South Beach

Common name

Scientific name

Winter

Spring

Summer

Fall

Average

Inland silverside

Menidia beryllina

1.00

0.96

0.96

0.92

0.96

Bay anchovy

Anchoa mitchelli

0.84

0.92

0.96

0.92

0.91

Southern kingfish

Menticirrhus americanus

0.80

0.85

0.96

0.96

0.89

Striped mullet

Mugil cephalus

0.88

0.58

0.88

0.92

0.81

Striped killifish

Fundulus majalis

0.52

0.69

1.00

0.67

0.72

Florida pompano

Trachinotus carolinus

0.20

0.50

1.00

1.00

0.68

Red drum

Sciaenops ocellatus

0.52

0.42

0.46

0.33

0.43

Striped anchovy

Anchoa hepsetus

0.16

0.38

0.65

0.50

0.42

Silver perch

Bairdiella chrysoura

0.64

0.46

0.19

0.33

0.41

Atlantic bumper

Chloroscombrus chrysurus

0.00

0.08

0.73

0.50

0.33

Hardhead catfish

Ariopsis felis

0.04

0.31

0.62

0.25

0.30

Spot

Leiostomus xanthurus

0.24

0.19

0.42

0.33

0.30

Star drum

Stellifer lanceolatus

0.36

0.31

0.35

0.17

0.30

Gulf kingfish

Menticirrhus littoralis

0.28

0.27

0.31

0.29

0.29

Bluefish

Pomatomus saltatrix

0.08

0.42

0.35

0.13

0.24

Average ubiquity

0.44

0.49

0.66

0.55

TABLE 3.8: Comparison of Archaeological and Modern South Beach Fish Diversity

Comparison

Diff. of means

t

P value

Critical level

Significant?

Archaeological vs. South Beach winter

1.030

4.54

<0.001

0.005

Yes

Archaeological vs. South Beach spring

0.824

3.52

0.002

0.006

Yes

South Beach summer vs. South Beach winter

0.912

3.05

0.005

0.006

Yes

South Beach summer vs. South Beach spring

0.697

2.33

0.028

0.007

No

Archaeological vs. South Beach fall

0.377

1.57

0.133

0.009

No

South Beach fall vs. South Beach winter

0.593

1.98

0.059

0.01

No

South Beach fall vs. South Beach spring

0.377

1.26

0.219

0.013

No

South Beach summer vs. South Beach fall

0.320

1.07

0.296

0.017

No

South Beach spring vs. South Beach winter

0.215

0.72

0.478

0.025

No

Archaeological vs. South Beach summer

0.127

0.52

0.612

0.05

No

Archaeological Data

A total of 6912 fish individuals representing 72 taxa are present in the archaeological collections (table 3.9). The most ubiquitous fishes (≥ 0.83) are, in order of ubiquity: seatrouts (Cynoscion spp.), mullets, gars (Lepisosteus spp.), Atlantic croakers (Micropogonias undulatus), hardhead catfishes (Ariopsis felis), gafftopsail catfishes (Bagre marinus), flounders (Paralichthys spp.), red drums, and star drums. The sea catfish family is as ubiquitous as seatrouts (1.0), but the archaeological reports of St. Simons Cannon’s Point and West rings and Bourbon Field record these taxa at the family level, reducing the ubiquity of the two species.

TABLE 3.9: Ubiquity of Fishes Identified in Some Georgia Bight Archaeological Collections(a)

Sapelo Ring III

St Cat

McQueen

Marsh Ring

West Ring

Ribault

FOY A

Cathead Ck

Kings Bay

Kenan

Bourbon

Cathead Ck

Kings Bay

JEA

FOY SJ

MHF

Back Ck

EPC

Pueblo

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Sw Creek

Sw Creek

Sav

Sav

Sav

Sav

Sav

SJ

Irene

Irene

17th c

17th c

Richness

71

21

31

36

25

16

26

11

19

27

15

19

16

26

16

27

7

26

16

14

Taxon

Ubiquity

Total

Cynoscion spp.

1.00

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

19

Mugil spp.

1.00

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

19

Lepisosteus spp.

0.95

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

18

Micropogonias undulatus

0.89

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

17

Ariopsis felis

0.84

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

16

Bagre marinus

0.84

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

16

Paralichthys spp.

0.84

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

16

Sciaenops ocellatus

0.84

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

16

Stellifer lanceolatus

0.84

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

16

Archosargus probatocephalus

0.79

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

15

Clupeidae

0.79

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

15

Pogonias cromis

0.79

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

15

Bairdiella chrysoura

0.74

1

1

1

1

1

1

1

1

1

1

1

1

1

1

14

Leiostomus xanthurus

0.68

1

1

1

1

1

1

1

1

1

1

1

1

1

13

Ariidae

0.47

1

1

1

1

1

1

1

1

1

9

Elops saurus

0.47

1

1

1

1

1

1

1

1

1

9

(a)See table 3.1 for references.

TABLE 3.9 — (Continued)

Sapelo Ring III

St Cat

McQueen

Marsh Ring

West Ring

Ribault

FOY A

Cathead Ck

Kings Bay

Kenan

Bourbon

Cathead Ck

Kings Bay

JEA

FOY SJ

MHF

Back Ck

EPC

Pueblo

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Sw Creek

Sw Creek

Sav

Sav

Sav

Sav

Sav

SJ

Irene

Irene

17th c

17th c

Richness

71

21

31

36

25

16

26

11

19

27

15

19

16

26

16

27

7

26

16

14

Taxon

Ubiquity

Total

Menticirrhus spp.

0.47

1

1

1

1

1

1

1

1

1

9

Pomatomus saltatrix

0.42

1

1

1

1

1

1

1

1

8

Rajiformes

0.42

1

1

1

1

1

1

1

1

8

Carangidae

0.32

1

1

1

1

1

1

6

Carcharhinidae

0.32

1

1

1

1

1

1

6

Ictalurus spp.

0.32

1

1

1

1

1

1

6

Opsanus sp.

0.32

1

1

1

1

1

1

6

Amia calva

0.26

1

1

1

1

1

5

Anguilla rostrata

0.26

1

1

1

1

1

5

Cyprinodontidae

0.26

1

1

1

1

1

5

Dasyatidae

0.26

1

1

1

1

1

5

Fundulus sp.

0.26

1

1

1

1

1

5

Lagodon rhomboides

0.26

1

1

1

1

1

5

Peprilus spp.

0.26

1

1

1

1

1

5

Ameiurus sp.

0.21

1

1

1

1

4

Dasyatus spp.

0.21

1

1

1

1

4

Myliobatidae

0.21

1

1

1

1

4

Belonidae

0.16

1

1

1

3

Brevoortia spp.

0.16

1

1

1

3

Chloroscombrus chrysurus

0.16

1

1

1

3

TABLE 3.9 — (Continued)

Sapelo Ring III

St Cat

McQueen

Marsh Ring

West Ring

Ribault

FOY A

Cathead Ck

Kings Bay

Kenan

Bourbon

Cathead Ck

Kings Bay

JEA

FOY SJ

MHF

Back Ck

EPC

Pueblo

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Sw Creek

Sw Creek

Sav

Sav

Sav

Sav

Sav

SJ

Irene

Irene

17th c

17th c

Richness

71

21

31

36

25

16

26

11

19

27

15

19

16

26

16

27

7

26

16

14

Taxon

Ubiquity

Total

Chondrichthyes

0.16

1

1

1

3

Citharichthys spp.

0.16

1

1

1

3

Orthopristis chrysoptera

0.16

1

1

1

3

Chaetodipterus faber

0.11

1

1

2

Diodontidae

0.11

1

1

2

Eleotridae

0.11

1

1

2

Galeocerdo cuvier

0.11

1

1

2

Ictaluridae

0.11

1

1

2

Prionotus sp.

0.11

1

1

2

Acipenser spp.

0.05

1

1

Carcharhinus spp.

0.05

1

1

cf. Chloroscombrus chrysurus

0.05

1

1

cf. Lamnidae

0.05

1

1

Chaenobryttus gulosus

0.05

1

1

Cyprinidae

0.05

1

1

Esox spp.

0.05

1

1

Larimus fasciatus

0.05

1

1

TABLE 3.9 — (Continued)

Sapelo Ring III

St Cat

McQueen

Marsh Ring

West Ring

Ribault

FOY A

Cathead Ck

Kings Bay

Kenan

Bourbon

Cathead Ck

Kings Bay

JEA

FOY SJ

MHF

Back Ck

EPC

Pueblo

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Archaic

Sw Creek

Sw Creek

Sav

Sav

Sav

Sav

Sav

SJ

Irene

Irene

17th c

17th c

Richness

71

21

31

36

25

16

26

11

19

27

15

19

16

26

16

27

7

26

16

14

Taxon

Ubiquity

Total

Lepomis spp.

0.05

1

1

Lobotes surinamensis

0.05

1

1

Menticirrhus americanus

0.05

1

1

Menticirrhus saxatilis

0.05

1

1

Odontaspis taurus

0.05

1

1

Ophidiidae

0.05

1

1

Peprilus paru

0.05

1

1

Raja eglanteria

0.05

1

1

Rhinoptera bonasus

0.05

1

1

Sardinella sp.

0.05

1

1

Sciaenidae

0.05

1

1

Serranidae

0.05

1

1

Sparidae

0.05

1

1

Sphyrna sp.

0.05

1

1

Symphurus spp.

0.05

1

1

Trichiurus lepturus

0.05

1

1

Trinectes spp.

0.05

1

1

Fish MNI

176

1121

1112

318

235

126

23

64

1672

231

398

61

853

157

204

32

334

75

54

7246

Comparison

Most high-ubiquity fishes in the modern South Beach collection also are present in Georgia Bight archaeological collections (fig. 3.11). The taxa in figure 3.11 are arranged in order of their ubiquity in the South Beach collection. The taxa labeled 1, 2, and 8 are small-bodied fishes (Menidia beryllina, Anchoa mitchelli, Anchoa hepsetus) that could be discriminated against by site formation processes or during archaeological excavations. However, taxon 5 is also a small-bodied fish (killifish, Fundulus majalis) and taxon 3 (southern kingfish) is generally a large fish when found in Georgia Bight archaeological collections. Mullets, taxon 4, are often small-bodied fishes in archaeological collections (e.g., Colaninno 2010: 51); though they grow to much larger sizes as adults, the larger size is more typical of Hispanic collections from sites further south, such as those from St. Augustine, than they are of pre-Hispanic collections. Mullets in many coastal archaeological collections are about the size of taxa 1, 2, 5, and 8, which are absent or rare in archaeological collections. Thus, recovery technique is not the only explanation for this pattern.

Instead, it appears that many of the fishes most ubiquitous in the South Beach collection are animals less commonly used in the past; supporting our premise that fishing was highly selective; fishes with lower modern ubiquity were favored over fishes with higher modern ubiquity by earlier fishing strategies. This conclusion is underscored by taxon 23. Taxon 23 is gar, a fish found in 95% of the archaeological collections from every time period and every location within the Georgia Bight. Gars are absent in the South Beach catch and rare in the Cumberland catch. Perhaps the conclusion to be drawn from figure 3.11 is that people did not often fish on the seaward side of barrier islands, where gars are rare or absent, but they did fish often in back-barrier locations, where longnose gars (Lepisosteus osseus) are found throughout the year (Dahlberg, 1972). It also is possible that this difference is a reflection of the lower freshwater input at St. Catherines, or may be an indication that more freshwater habitats once existed between St. Catherines Island and the mainland and on the island itself, particularly if the island once extended further east than it does today.

Figure 3.12 shows the present-day seasonal ubiquity of eight fishes with high ubiquity in either the modern South Beach (≥ 0.30) or archaeological (≥ 0.68) collections. The first observation is that all but one of these fishes is present throughout the year; the primary pattern is a seasonal shift in relative ubiquity. The standard seasonal markers that may be used elsewhere fail in this context. The second observation is that some fishes are more ubiquitous than are others during one or more season. Mullet, red drums, and star drums are unlikely to be helpful as seasonal markers, whereas hardhead catfishes might be strong markers for warmer waters and silver perches (Bairdiella chrysoura) moderately strong markers for cooler waters. Similar ubiquity data are not available for Cumberland Sound but most taxa with ubiquity ≥ 0.68 in the archaeological record are present during at least three, if not four, of the seasons at Station E in the Kings Bay area (fig. 3.13; DEIS, 1978: D438–D445).

Species diversity of archaeological data (H’ = 2.06) is significantly higher than modern South Beach data (H’ = 1.48). Diversity of the archaeological collections is significantly different than the diversity of modern winter and spring South Beach collections, but not when compared with the fall and summer samples (table 3.8; fig. 3.5).

Fig. 3.11. Comparison of South Beach and archaeological fish ubiquity. 1, Menidia beryllina; 2, Anchoa mitchelli; 3, Menticirrhus americanus; 4, Mugil cephalus; 5, Fundulus majalis; 6, Trachinotus carolinus; 7, Sciaenops ocellatus; 8, Anchoa hepsetus; 9, Bairdiella chrysoura; 10, Clupeidae; 11, Chloroscombrus chrysurus; 12, Ariopsis felis; 13, Leiostomus xanthurus; 14, Stellifer lanceolatus; 15, Menticirrhus littoralis; 16, Pomatomus saltatrix; 17, Cynoscion spp.; 18, Pogonias cromis; 19, Bagre marinus; 20, Micropogonias undulatus; 21, Paralichthys spp.; 22, Archosargus probatocephalus; 23, Lepisosteus spp.

Fig. 3.12. Seasonal ubiquity of selected fish taxa in the South Beach collection.

DISCUSSION

The purpose of this chapter is to consider evidence for season of availability in modern fishes as a means of clarifying season of activity and location for people living in the Georgia Bight in the past. Although this study focuses on those fishes that form the core of the Georgia Bight fishery, many other organisms, including fungi, plants, invertebrates, reptiles, mammals, and birds, supplemented these fishes. This flexible subsistence strategy is reflected in a moderate vertebrate diversity (H’ = 2.890, MNI) and high vertebrate equitability (V’ = 0.841, MNI) before the advent of the First Spanish period in a.d. 1565 (Reitz et al., 2010: 63, 72, 233–234).

In this study, modern data show clear seasonal patterns in the availability of fishes. Characteristics such as abundance, biomass, diversity, dominance, distribution, ubiquity, and body size, however, are relative rather than absolute and may depend on location and gear as much as on season. Organisms characteristic of estuaries are those best able to withstand the biogeochemical and hydrological conditions that define estuaries. Resource seasonality does occur in the Georgia Bight, but many fishes identified in archaeological collections are present somewhere in estuarine waters throughout the year, depending on whether they are young fishes using estuaries as nurseries or adults using them as feeding grounds.

Fishing in the Georgia Bight was highly selective, focused specifically on a core group of indicator taxa that occupy estuarine waters throughout the year. Many of these core fishes either school or form large aggregations, making them susceptible to mass-capture techniques (Reitz, Quitmyer, and Marrinan, 2009; Reitz et al., 2010: 234–237). These same high-ubiquity, core fishes generally are not high-ubiquity taxa in standard fishing samples taken under modern conditions, however. Although this may be strong evidence that major environmental changes in estuarine ecosystem functions have occurred, it is also true that the ability of ecological analogies using fish presence and ubiquity to provide answers to questions of season of human activity and location is limited. The answer to season of availability, however, is that taxa in the core fishing group were available somewhere in the upper or lower reaches of the estuary throughout the year.

Difficulties in correlating resource availability with the synchronic biogeochemical and hydrological properties that define seasons are compounded by diachronic changes in the niche and habitat preferences of fish individuals as they mature. Age cohorts are mobile and seek out preferred environmental properties throughout the estuary and beyond during an annual cycle. This produces patterns such as those observed in the mean total length of star drum on South Beach (fig. 3.14). Mean total length of this small fish increases substantially in the fall, as mature individuals leave the estuary, even as their abundance decreases (fig. 3.12). Young fishes are more tolerant of estuarine conditions than are most adult fishes. Combining presence data with measurements of fishes may be more productive than presence and ubiquity analysis in assessing season of availability by considering the seasonal aspects of age cohorts, though one would still need to know location of capture for larger and smaller fishes and the influence of gear on this evidence for season of availability.

Modern studies suggest that shallow, warm, low-energy waters with salinity and nutrient levels typical of middle and upper reaches were preferred fishing grounds. Beaches were used less frequently than were back-barrier areas. Although modern data clearly indicate when and where fishing would be productive today, it is unlikely that these precise locations were equally productive in the past because the topography of each estuary probably has changed. Identifying specific places where fishing occurred is unlikely.

Where fishing took place and the gear used undoubtedly changed during the annual cycle given the different locations the most ubiquitous fishes occupy within estuaries during the year. Fishing, likely using watercraft, probably followed the preferred, targeted fish taxa within each estuary (e.g., Ames, 2002). The distances are not great, probably no more than 10–12 km depending on where the fishing party started and where it was going. We suggest “party” intentionally because many ubiquitous fishes are susceptible to technologies such as weirs and nets that are most effective in shallow waters where tidal ranges are large enough to overtop the enclosure at high tide. Such facilities usually require several people to work and frequent repairs, but the labor of people of all ages and abilities would be useful. Although the distance from most places on St. Catherines Island to daily or annually productive fishing grounds would not have been great, fishing parties would have to be mindful of going against strong incoming or outgoing tides.

Embedded in the archaeological literature is the assumption that coastal life is difficult and coastal residence must be forced upon people by necessity (for reviews of these perceptions see Erlandson, 2001 and Ames, 2002). Despite Monks (1981) admonition that residential patterns are not clearly related to season of availability, it is typically presumed that people lived on the coast only during the warmer months, residing elsewhere during the remainder of the year. The assumption that fishing communities must be mobile fundamentally links season of availability with season of location. Thus resource availability, subsistence schedules, residential habits, political institutions, and social complexity are merged in many models. Residential patterns themselves are often reduced to a dichotomy of mobility on the one hand and sedentism on the other, as though these were mutually exclusive options. As Bar-Yosef and Rocek (1998: 1, italics theirs) argue: “The fact is all societies have a mobility component; the issue is what the form of that mobility is, not whether it exists.” As with most cultural institutions, the forms, causes, and consequences of resource acquisition and residential patterns are diverse.

Interpretations of coastal life labor under a particularly inflexible assumption that a farming subsidy is required to support people throughout an annual cycle or to support complex social institutions. Although it has been demonstrated repeatedly that nonfarmers with complex social institutions did exist in coastal settings (e.g., Kennett and Kennett, 2000; Builth, 2006), the question remains unresolved in the minds of many. A quarter of all the fish taxa present in Georgia Bight archaeological collections is present in over 60% of the collections, regardless of whether the site is an Archaic shell ring or a 17th-century Spanish mission. This suggests that the kinds of fish, though perhaps not the technology, have been little altered over the centuries, regardless of the cultural matrix of which fishing was but one aspect (Reitz, 2004). This is not to suggest that there were no changes either in the resource base or in the cultural use of that base; we know that there were. Throughout the period, however, fishing was a major and consistent aspect of daily life; drawing upon the ability of both the fishes in the core group and people to be flexible in an environment that changes with each tide.

A suite of concepts draws upon human behavioral ecology, specifically optimal foraging theory, to interpret fishing strategies (e.g., Habu, 2002; Ugan, 2005; Winterhalder and Kennett, 2006; Culleton, Kennett, and Jones, 2009). In archaeological applications, these concepts are important because it is essential to distinguish between anthropogenic and nonanthropogenic impacts on biological resources to assess causality in environmental change and resilience in specific fisheries, important issues in conservation biology and fisheries management (e.g., Butler and Delacorte, 2004; Broughton, 2010).

Among these concepts are those that distinguish between subsistence-settlement systems of foragers and collectors (e.g., Binford, 1980; Bettinger, 1991: 68; Habu and Fitzhugh, 2002; Broughton, 2010). Although “forager” is often used as a substitute for “hunter-gatherer,” in many optimal foraging models foraging forms one end of a continuum with collecting at the other end. When used in this sense, foraging systems are said to occur in areas with high productivity and resources that are seasonally and spatially homogeneous. Collector systems occur in areas with low productivity and resources that are seasonally or spatially uneven. Foragers acquire food each day near their residential base and are residentially mobile; all members move to another location when resources are judged to be inadequate. Such opportunistic foraging is only feasible if resources can be transported over a short distance. Collectors, on the other hand, implement planned, logistic strategies that may exploit resources over a larger area, usually produce larger yields, and are implemented by specialized task groups. Such logistically mobile collectors bring resources back to the residential base, where they may be stored. A foraging radius, therefore, is close to the base camp and a logistic/collecting radius is further away. Collectors, too, may move their residential bases seasonally, though storage may reduce the scope of this mobility. Coastal foragers, therefore, should be characterized by low logistical mobility and high residential mobility and coastal collectors by high logistical mobility and low residential mobility.

Some research in coastal settings, however, suggests that considerably more flexibility and variety than a simple dichotomy between foragers and collectors characterize fishing in such areas (Ames, 2002; Habu, 2002; Habu and Fitzhugh, 2002; Butler and Campbell, 2004). Fishing in the Georgia Bight appears to be another example not easily accommodated in either of these models. Generalizing broadly, the Georgia Bight could be considered a high productive area with resources that are seasonally and spatially uneven.

The estuaries of the Georgia Bight are among the most productive and complex on the Atlantic coast, with about four times as much marsh per kilometer of coastline as other areas of the Atlantic seaboard (Schelske and Odum, 1961; Hayden and Dolan, 1979: 1063; Frey and Howard, 1986). Resources, however, are not seasonally or spatially homogeneous; they are spatially and temporally patchy in addition to being highly mobile in the case of vertebrates. Neither are they likely to be depleted within an annual cycle to such an extent that it would stimulate residential mobility because the fishery is renewed with each tidal cycle. It is entirely possible that the fishery could be, and was, depressed by overfishing or other drivers of long-term environmental change from time to time (e.g., Reitz, 2004; Quitmyer and Reitz, 2006; Reitz, Quitmyer, and Marrinan, 2009), but the broad features of the core fishing strategy persisted, nonetheless. A similar conclusion is reported for other fisheries (Butler and Campbell, 2004).

People likely did fish more or less each day and return the food to a residential base but are unlikely to have moved elsewhere if fishing deteriorated at a favored fishing ground; the distances on any of the islands or within estuaries would be well within the 30 km estimated for a coastal foraging radius (Ames, 2002). More likely the travel distance for fishing was much less throughout the year. It is entirely likely that fishing would be less productive at a specific location during the year given the preferences of fish age cohorts, populations, and communities for different locations during the annual growth and reproductive cycles of each species, but it is unlikely that all fishes in the core strategy would move so far away that they could not be reached from any residential base within most estuaries in the Georgia Bight. Likely only task groups were involved in each fishing foray. The potential exists for large quantities of fish to be taken, though storing fish may not have been appealing in this subtropical, humid region.

We suspect good places to build homes, secure water craft, shelter from wind and sand fleas, and dry nets might be limited and highly prized. These would be abandoned with great reluctance in response to such larger factors as a reconfiguration of the coastline after a storm, but not because of factors that are said to characterize either opportunistic foragers or logistical collectors.

Another key concept is the role of plant domestication. Plants and animals provide different types of nutrients. It is unlikely that a sustainable coastal economy was based exclusively on either plant or animal nutrients. Plants and animals also provide different types of raw materials and play different roles in social life. Thus, people living in the Georgia Bight, as broad-spectrum omnivores, undoubtedly used both plants and animals, some of which were terrestrial and some aquatic. When or whether some plants were at least tended if not domesticated is poorly known for the Georgia Bight, but eventually some domestic plants did enter the economy (see Scarry and Hollenbach, chap. 11, this volume). This does not appear to have altered the fishing strategy in any measurable way, though it may have impacted residential and fishing decisions as scheduling conflicts were resolved (e.g., Flannery, 1968).

Sarah Campbell and Virginia Butler (2010) argue that beliefs and social institutions (such as ownership, regulations, rituals, and monitoring) might foster resilience in coastal ecosystems. They report a 7500-year-long record of stability in a Pacific Northwest salmon fishery that may be evidence for the regulation of salmon fishing by cultural institutions in the region, thereby encouraging persistence in the fishery. A similar long-term fishery is seen in the Georgia Bight. It is probable that kin groups or other social units owned the rights to specific fishing grounds and the facilities constructed at each. We consider it unlikely that fishing networks would fail to safeguard their rights to such valuable assets, even during brief absences for social or economic reasons (e.g., Nishimura, 1975; Builth, 2006). The possibility that members of these fishing communities intentionally modified estuarine conditions to encourage a variety of estuarine plants and animals, much as they might manipulate habitats preferred by terrestrial organisms, is intriguing (e.g., Erickson, 2000; Builth, 2006; Campbell and Butler, 2010). As Butler and Campbell (2004: 373) report for Pacific coast salmon fishing, the core fishes in Georgia Bight archaeological collections are among the most widespread and abundant fish prey. Their role in the fishery persisted from ca. 2560 b.c. until the beginning of the First Spanish period, in fact, continuing to be prominent components of subsistence strategies in EuroAfrican colonial towns and plantations thereafter (Reitz, 1994; Reitz et al., 2010). This fishery undoubtedly experienced cycles of crisis and recovery, but it was sufficiently flexible and resilient to endure despite cultural and environmental changes over the millennia.

Other factors complicate studies of season of availability in the Georgia Bight. Many animals used in the past are available throughout the year at several different locations. Although they may move, reproduce, or grow seasonally, these details are difficult to determine from zooarchaeological observations such as taxonomic identifications, taxonomic frequencies, element distribution, measurements, age at sexual maturity, and season of death. Isotopic ratios and growth increments may demonstrate that an organism died during one part of the annual temperature or growth cycle; but not the contemporaneity of other sites that might be part of a seasonal round. Technologies and other aspects of subsistence strategies can leave vertebrate evidence that diverges widely from background resource bases, as seen in this study. Storage, production, and exchange systems could leave little unambiguous evidence at the site under study. Exchange networks within an extended family or on a broader scale have the purpose of rounding the shortfalls associated with poor weather, poor skills, and bad luck.

Estuaries are characterized by continuity and stasis rather than change in large part because of the inherent flexibility of organisms that use estuaries as nursery grounds. Such taxa could withstand significant exploitation, and alterations associated with top-down and bottom-up processes regardless of the cause. That many estuarine organisms are no longer able to maintain former population sizes and community structures, and now are in decline, should be cause for alarm among coastal resource managers.

Fig. 3.13. Number of seasons in which fishes with archaeological ubiquity ≥ 0.68 are present at Station E, Cumberland Sound (DEIS, 1978: D-438–D-445).

Fig. 3.14. Seasonal aspects of mean total length (in cm) of star drum (Stellifer lanceolatus) in the South Beach collection.

CONCLUSION

Estuarine fishes are attracted to back-barrier reaches as nursery grounds and feeding areas. The potential of estuaries to fill these roles varies seasonally. Our analysis indicates that the fish communities and populations forming the core fishing strategy into the 17th century are available in shallow waters throughout the year, albeit in different locations and probably vulnerable to different capture techniques. Seasonality in the Georgia Bight appears to be more a question of where and how rather than what or when.

In order to engender hope for determining season of activity and location, studies must combine observations for communities of organisms with information about the biogeochemical and hydrological properties preferred by ubiquitous taxa. Indicator groups are useful for studies such as the one in this chapter, however, syntheses of biotic, abiotic, and cultural data to form indicator packages are needed before we can address the questions of where and how. Indicator packages are difficult to develop and seldom achieved. The first step toward this goal is to ensure that a wide range of evidence is included in the research project through thoughtful fieldwork and multiproxy studies. The full suite of environmental studies should be performed with equal rigor at all sites that might be part of a seasonal round, exchange network, kin group, or other social unit to systematically explore how sites of different sizes and functions fit into the overall landscape, and how patterns of season, activity, and location change through time and space.

CHAPTER 4: EVALUATING δ18O PROFILES OF HARDHEAD CATFISH AND ATLANTIC CROAKER OTOLITHS AS A METHOD OF DETERMINING SEASONAL USE OF FISHES

Carol E. Colaninno[15]

Documenting seasonal resource use among human populations is a central aspect of archaeological research. For coastal locations of the southeastern United States, studies of seasonal resource use have focused on molluscs, and for good reason. Molluscs, including oysters (Crassostrea virginica) and hard clams (Mercenaria spp.), generally are abundant at these locations; there is a correlation between incremental formation and yearly, seasonal environmental oscillations; and shell CaCO3 (calcium carbonate) precipitates in oxygen isotope equilibrium with the ambient water in which shell forms (Grossman and Ku, 1986; Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2000; Andrus and Crowe, 2008). This allows researchers to examine patterns in incremental formations and the ratio of stable oxygen isotopes (18O/16O, expressed as δ18O) at the terminal band and in prior bands to determine the season in which people captured the organism (Quitmyer, Hale, and Jones, 1985; Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2000, 2008; O’Brien and Thomas, 2008; Thompson and Andrus, 2011). These studies were instrumental in documenting year-round occupations, as well as locations used seasonally (Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2008; Thompson and Andrus, 2011).

Although oyster and hard clam studies are essential for characterizing seasonal resource use, they do so for only two organisms, oysters and clams. Zooarchaeological research at coastal southeastern sites shows that over a hundred different animals were used in the past, in addition to oysters and clams (Colaninno, 2010; Reitz et al., 2010: 54–57; Reitz et al., chap. 3, this volume). These resources include a diverse array of estuarine fishes along with numerous other aquatic and terrestrial animals. Investigating seasonal use of nonmolluscan taxa, particularly fishes, provides further information about past land and estuarine use patterns, resource intensification, and social complexity. It is an area of research that largely is unexplored in the southeastern United States.

This chapter examines seasonal use of two fish species: hardhead catfish (Ariopsis felis) and Atlantic croaker (Micropogonias undulatus). I examine δ18O[otolith] profiles of modern hardhead catfishes and Atlantic croakers to determine whether δ18O[otolith] profiles track seasonal temperature oscillations. Seasonal temperature oscillations observed in modern δ18O[otolith] are applied to archaeological δ18O[otolith] to determine past seasonal temperature oscillations and the season in which people captured these fishes. The archaeological otoliths are from four Late Archaic shell rings (2550–1500 cal b.c.) located on the Georgia coast: the Cannon’s Point (9GN57) and West rings (9GN76) of St. Simons Island, and the St. Catherines (9Li231) and McQueen shell rings (9LIi648) of St. Catherines Island (fig. 4.1).

Shell rings are complex structures having intricate stratigraphic sequences representing multiple cultural and natural processes (Marrinan, 2010: 80; Sanger and Thomas, 2010: 55; Kennett and Culleton, chap. 2, this volume; Thompson and Andrus, 2011). Radiocarbon dates indicate that otoliths from the Cannon’s Point Ring were deposited between 2760 ± 120 cal b.c. and 2200 ± 140 cal b.c. (Marrinan, 2010: 81). Dates from the West Ring indicate deposition between 2320 ± 120 cal b.c. and 1970 ± 160 cal b.c. (Marrinan, 2010: 81); however, dates were not obtained from locations where otoliths were sampled. Deposition from the location in which otoliths were sampled from the St. Catherines Shell Ring dates between 2580 and 1770 cal b.c. (Sanger and Thomas, 2010: 62). Dates from the McQueen Shell Ring suggest deposition between 2460 and 1850 cal b.c. (Sanger and Thomas, 2010: 63); however, materials were not dated from locations where otoliths were sampled.

Fig. 4.1. Map of study area showing location of shell rings.

METHODS

I chose hardhead catfishes and Atlantic croakers because their otoliths are ubiquitous in these four shell ring collections (Colaninno, 2010). Additionally, these two species have relatively large otoliths that are identifiable to species and easily handled.

Seasonal use of archaeological hardhead catfishes and Atlantic croakers is estimated by analyzing the seasonal variation recorded in δ18O[otolith] in relation to environmental oscillations. The original research design was to capture modern hardhead catfishes and Atlantic croakers each month for one year to ensure that δ18O[otolith] profiles track seasonal temperature fluctuations. Unfortunately, monthly fishing trips did not always result in the capture of a fish. To supplement the modern otolith study, I selected hardhead catfish and Atlantic croaker otoliths for isotopic analysis from individuals with known dates and locations of capture and biological measurements curated in the zooarchaeological comparative collection of the Georgia Museum of Natural History and the environmental archaeology program of the Florida Museum of Natural History. I analyzed 24 modern otoliths, 12 from each species (appendix 4.1).

I selected 42 archaeological otoliths for δ18O analysis using several criteria. Archaeological otoliths first were examined for evidence of burning or leaching. These taphonomic processes affect δ18O of preserved CaCO3 (Andrus and Crowe, 2002). Additionally, only complete otoliths with lengths greater than 7.0 mm were selected because it is difficult to section smaller otoliths without destroying them. Otherwise, I sampled the full size range of otoliths in each archaeological collection. Only left otoliths of both archaeological and modern individuals were sampled. For the archaeological specimens this ensured that each otolith represents a different individual. Unfortunately, these criteria excluded many otoliths, and more otoliths were sampled from some shell rings than from others (appendix 4.2).

The archaeological otoliths were immersed in distilled water for 24 hours and then brushed with a nylon-polyester blend bristled toothbrush to remove adhering sediments from the exterior surface before they were cross-sectioned. I immersed the modern otoliths in 30% H2O2 solution for 12 hours and rinsed them in distilled water to remove organic contaminates. After all otoliths were cleaned, I cross-sectioned each otolith along the transverse plane through the center of the core with a Buehler Isomet low-speed diamond-wafering saw model 11-1280-160 to expose the otolith’s cross section. I then attached each otolith section to a glass microscope slide with crystal bond, polished the otolith section to a flat surface, again rinsed the specimen with distilled water, and allowed each specimen to air dry completely.

Isotopic analysis of fish otoliths was conducted at the University of Alabama stable isotope laboratory with a New Wave/Merchantek micromill. Multiple drilling paths were interpolated across the cross-sectioned surface. Several drilling paths were sampled from some growth bands, depending on the size of the band. In some cases, however, growth bands were too small to drill a single isolated band and two bands were included in one drilling path sample. Drilling paths were spaced across the cross-sectioned surface of the otolith at regular intervals of approximately 0.1–0.2 mm. This method of drilling sampled growth bands through reserved ontogenic sequence; that is from the terminal edge through the core (all δ18O[otolith] are plotted through ontogeny in the figures). For hardhead catfish otoliths, I sampled the entire cross-sectioned surface (fig. 4.2). For Atlantic croaker otoliths, I sampled the medial surface (surface with sulcus) to the center core (fig. 4.3). I did not sample the lateral surface of Atlantic croaker otoliths because portions of the knobby texture on the lateral surface often were not present on archaeological specimens. The complete length, width, and medial surfaces were present on all studied otoliths. I noted the location of each drilling path within the otolith and within the growth band during isotopic sampling when incremental bands clearly were definable and visible using the microscopic feature of the New Wave/Merchantek micromill.

Micromilling the sectioned surface of the otolith produced a powdered sample. I cleaned the microdrill with compressed air after every sample to prevent cross-contamination. These samples were exposed to phosphoric acid to generate CO2 gases, which were processed by a Finnigan Mat Delta-E isotope ratio mass spectrometer. Working standards also were processed after every seventh sample to ensure precision and accuracy of the mass spectrometer.

Results of this analysis yielded raw oxygen isotopic signatures that were processed and reported in per mil (‰) units with respect to VPDB (Vienna Pee Dee Belemnite Standard). Precision was estimated and data were calibrated to VPDB through analysis of the NBS-19 standard. Precision ranges from 0.08‰ and 0.37‰. Averaged precision of all samples is 0.17‰ (1σ).

Temperatures (T) are calculated with δ18O[otolith] using the Grossman and Ku (1986) aragonite precipitation equation where T is temperature in degrees Celsius:

δ18O[otolith] (PDB) = [(T–20.6/–4.34)] + δ18O[water (SMOW)].

I use several values for δ18O[water (SMOW)], which are stated in the various temperature estimates.

Fig. 4.2. Cross section of hardhead catfish otolith, FLMNH-EA 11341. Black lines represent drilling path examples for δ18O sampling. Multiple drilling paths were taken from each otolith. For example, 28 drilling paths were sampled from FLMNH-EA 11341 across the entire surface of the otolith, within incremental bands.

Fig. 4.3. Cross section of Atlantic croaker otolith, FLMNH-EA 11319. Black lines represent drilling path examples for δ18O sampling. Multiple drilling paths were taken from each otolith. Nine drilling paths were sampled from FLMNH-EA 11319 across the medial surface (surface with sulcus) to the center core, within incremental bands.

δ18O[otolith] FRACTIONATION FACTORS AND ESTUARINE ENVIRONMENTS

Otoliths precipitate in oxygen isotopic equilibrium with ambient waters in which the otolith forms (Devereux, 1967; Hoefs, 1997; Thorrold et al., 1997). δ18O[otolith] covaries with water temperature and δ18O[water]. If δ18O[water] can be held constant, δ18O[otolith] can be used to estimate the water temperature in which the fish lived (Thorrold et al., 1997; Andrus et al., 2002). When δ18O[otolith] is plotted through ontogeny, seasonal temperature oscillations should be observed, and the δ18O[otolith] samples prior to and at the terminal edge of growth can determine the approximate temperature the fish experienced when it was captured.

For estuarine environments, such as those surrounding Georgia Sea Islands, δ18O[water] cannot be held constant and temperature calculations from δ18O[otolith] will not be the actual temperature. This is because inputs of fresh water, with lower salinities compared to sea water, alter δ18O[water]. Estuaries are, by definition, areas of partly enclosed water with freshwater inputs. In some regions of the world, freshwater inputs are seasonal and δ18O[otolith] tracks these seasonal changes in salinity, which can indicate season of capture (Kennett and Voorhies, 1996). In other regions, freshwater influxes are erratic, complicating δ18O[water].

To understand oscillations in δ18O[otolith], modern oscillations in temperature and salinity for Georgia estuaries must be considered. Water temperatures of Georgia estuaries (fig. 4.4) generally oscillate over a seasonal range of approximately 20°C (http://cdmo.baruch.sc.edu/ data from Marsh Landing, Sapelo Island water data year 2003; Andrus and Crowe, 2008). Warmest temperatures occur from June to August, and coolest temperatures occur from December to February (http://cdmo.baruch.sc.edu/ data from Marsh Landing, Sapelo Island water data year 2003; Andrus and Crowe, 2008). Freshwater inputs and salinity also vary, both spatially and temporally. Monthly average salinity generally ranges between approximately 16‰ and 31‰ (http://cdmo.baruch.sc.edu/ data from Marsh Landing, Sapelo Island, water data, years 1996 and 2003), although lower salinity values are reported (Thompson and Andrus, 2011). Unlike temperature oscillations, salinity does not vary seasonally and no regular salinity cycle is observed, apart from those associated with daily tidal cycles (fig. 4.4).

Unpredictable salinity fluctuations make accurate temperature estimations with δ18O[otolith] problematic. If δ18O[water] values can be held constant (e.g., seawater), δ18O[otolith] could accurately estimate temperatures. The δ18O[otolith] sample of the terminal increment combined with the sample just prior to the terminal increment could establish seasonal temperature fluctuations and the season in which people captured the fish. I demonstrate this using data from Andrus and Crowe (2008) and the Grossman and Ku (1986) aragonite precipitation equation. With recorded temperature, salinity, and a constant δ18O[water] value as the average water value of –0.9‰ from monthly collections, estimates of δ18O[otolith] are calculated (Andrus and Crowe, 2008).

As seen in figure 4.5, when δ18O[water] is held constant, δ18O[otolith] accurately reflects seasonal temperature oscillations. That is, the most enriched δ18O[otolith] would precipitate during coolest months, winter, while the most depleted δ18O[otolith] would precipitate during warmest months, summer.

Figure 4.5 models the ideal circumstance for using δ18O[otolith] to estimate season of capture, but this does not occur in estuarine waters of the Georgia coast. δ18O[water] fluctuates due to both seasonal temperature oscillations and erratic salinity fluctuations. Thus, the δ18O[otolith] profiles are more complex than figure 4.5 suggests.

Using actual monthly measured δ18O[water] (range from –2.2‰ to 0.4‰) from Andrus and Crowe (2008), a model (fig. 4.6) is generated based on the Grossman and Ku (1986) aragonite precipitation equation. From figure 4.6, a semisinusoidal pattern in estimated δ18O[otolith] is seen. Estimated δ18O[otolith] values are depleted during warmest months, while enriched values form during coldest months. Salinity complicates estimated δ18O[otolith] values, however. For example, in October, the temperature is 22.8°C, but δ18O[water] is depleted due to low salinity levels from fresh water, generating more depleted δ18O[otolith] values.

To examine effects of fluctuating δ18O[water] on δ18O[otolith], I examined modern otoliths for seasonal δ18O[otolith] oscillations, converting δ18O[otolith] to temperature in degrees Celsius, with a constant δ18O[water] of –0.9‰ (the yearly average δ18O[water] from waters surrounding St. Catherines Island [Andrus and Crowe, 2008]). These temperature values are approximations of the actual temperature the fish experienced.

Fig. 4.4. A. Mean temperature per month for 2003 with recorded temperature maximums and minimums at Sapelo Island Marsh Landing. B. Mean salinity per month for 2003 with recorded salinity maximums and minimums. See http://cdmo.baruch.sc.edu/ for Marsh Landing, Sapelo Island, water data.

Fig. 4.5. Annual cycle of temperature oscillation and salinity fluctuations for the McQueen Inlet of St. Catherines Island, Georgia (Andrus and Crowe, 2008). Estimated δ18O[otolith] is based on an average and constant δ18O[water]. Calculation based on Grossman and Ku (1986).

Fig. 4.6. Annual cycle of temperature oscillation and salinity fluctuations for the McQueen Inlet of St. Catherines Island, Georgia (Andrus and Crowe, 2008). Estimated δ18O[otolith] is based on a recorded δ18O[water] (Andrus and Crowe, 2008). Calculation based on Grossman and Ku (1986).

δ18O OF MODERN OTOLITHS

When the modern hardhead catfish δ18O[otolith] are plotted through ontogeny, oscillations in δ18O[otolith] are observed, reflecting seasonal temperature oscillation (fig. 4.7A). In 75% of the examined otoliths, the terminal and penultimate δ18O[otolith] values record seasonal temperature fluctuations correlating with the expected season in which the hardhead catfish was captured (table 4.1).

Like the modern hardhead catfish δ18O[otolith], the modern Atlantic croaker δ18O[otolith] show semisinusoidal oscillations in δ18O[otolith] when plotted through ontogeny, recording seasonal temperature oscillations (fig. 4.7B). The modern Atlantic croaker δ18O[otolith] correctly predicted the season of capture in 83% of the sample, which is a higher level of accuracy compared to hardhead catfish δ18O[otolith] (table 4.2).

Fig. 4.7. A. Modern hardhead catfish (FLMNH-EA 11271) δ18O[otolith] captured in August 1979, Walburg Creek, St. Catherines Island. δ18O[otolith] indicates that this individual was captured when water temperatures were warm. B. Modern Atlantic croaker (GMNH-EA 4462) δ18O[otolith] captured in June 2009, North Beach, St. Catherines Island. δ18O[otolith] indicates that this individual was captured when water temperatures were warm.

TABLE 4.1: Modern Hardhead Catfish Otolith Season of Capture and Estimated Season of Capture

Catalog no.

Date captured

Season captured

Estimated season captured δ18O[otolith]

GMNH 2172

5/10/81

Spring

Spring

GMNH 4457

6/27/09

Summer

Spring

GMNH 1732

7/25/80

Summer

Summer

GMNH 4269

7/31/03

Summer

Summer

FLMNH-EA 11162

8/9/79

Summer

Summer

FLMNH-EA 11271

8/9/79

Summer

Summer

FLMNH-EA 11341

8/9/79

Summer

Summer

GMNH 4472

8/22/09

Summer

Summer

GMNH 4470

8/22/09

Summer

Summer

GMNH 4295

9/16/03

Summer

Spring

GMNH 4469

9/19/09

Summer

Summer

GMNH 4468

9/19/09

Summer

Summer

TABLE 4.2: Modern Atlantic Croaker Otolith Season of Capture and Estimated Season of Capture

Catalog no.

Date captured

Season captured

Estimated season captured δ18O[otolith]

GMNH 1075

3/1/80

Winter

Winter

GMNH 4475

4/25/09

Spring

Spring

GMNH 4458

5/23/09

Spring

Spring

GMNH 3762

5/29/87

Spring

Spring

GMNH 4462

6/27/09

Summer

Spring

FLMNH-EA 11313

8/8/79

Summer

Summer

FLMNH-EA 11318

8/8/79

Summer

Summer

FLMNH-EA 11319

8/8/79

Summer

Summer

GMNH 4473

8/27/09

Summer

Summer

GMNH 4474

8/27/09

Summer

Summer

GMNH 4471

9/18/09

Summer

Indeterminate

GMNH 4476

9/18/09

Summer

Summer

δ18O OF ARCHAEOLOGICAL OTOLITHS

In 75% of modern hardhead catfish otoliths and 83% of modern Atlantic croaker otoliths, modern δ18O[otolith] accurately indicated the season in which the fish died. As such, δ18O[otolith] profiles of archaeological specimens can indicate the season in which people captured the fish. The archaeological δ18O[otolith] sample just before terminal growth and at terminal growth, in addition to δ18O[otolith] fluctuations experienced through ontogeny, are used to characterize temperature fluctuations occurring when the fish died. Little to no temperature difference is noted between seasonal transitions, for example March 20 (the last day of winter) and March 21 (the first day of spring) (http://cdmo.baruch.sc.edu/ data from Marsh Landing, Sapelo Island water data years 1996 and 2003). The application of seasonal classification using archaeological δ18O[otolith]s does not directly equate to the actual season, but rather, winter is indicated by cold temperatures, spring is suggested by the transition of cold to warm temperatures, summer is indicated by warm temperatures, and fall is suggested by a warm to cold temperature transition. If all four seasons are represented in the archaeological δ18O[otolith] profiles from a site, fishing likely occurred during all four seasons. The Grossman and Ku (1986) aragonite precipitation equation is used to convert δ18O[otolith] to temperature in degrees Celsius, with the constant δ18O[water] of –0.9‰ for the following analysis (fig. 4.8A–D and 9).

Fig. 4.8. δ18O[otolith] through ontogeny. A. Atlantic croaker (FLMNH-EA 01550585) δ18O[otolith] profile indicating cold temperatures, or winter season of death from the Cannon’s Point Ring. B. Atlantic croaker (FLMNH-EA 01610214) δ18O[otolith] profile indicating a cold to warm temperature transition, or spring season of death from the West Ring. C. Atlantic croaker (GMNH 02381886) δ18O[otolith] profile indicating a warm, or summer season of death from the St. Catherines Shell Ring. D. Atlantic croaker (FLMNH-EA 01610169) δ18O[otolith] profile indicating a warm to cold temperature transition, or fall season of death from the West Ring.

Fig. 4.9. Archaeological δ18O[otolith] of an Atlantic croaker (FLMNH-EA 01610231) approximately 18.5 years of age. δ18O[otolith] during 17.5 years of noncore growth ranges between –0.25‰ and 1.05‰ or a 5.7°C difference in experienced temperature.

The Cannon’s Point Ring

Only one of the two otoliths examined from the Cannon’s Point Ring yielded conclusive results, FLMNH-EA 01550585 (table 4.3). This Atlantic croaker otolith indicates that the fish died while temperatures were cold, suggesting that people fished at least during winter (fig. 4.8A).

The West Shell Ring

I analyzed two hardhead catfish and six Atlantic croaker otoliths for δ18O[otolith] profiles from the West Ring (table 4.3). People who formed this ring captured one hardhead catfish during summer (FLMNH-EA 01610161) and one during fall (FLMNH-EA 01610027). One Atlantic croaker otolith yielded inconclusive results (FLMNH-EA 01610231). Three Atlantic croakers were captured during winter (FLMNH-EA 01610169, 01610194, and 01610214), one was captured in the spring (FLMNH-EA 01610214), and one was captured during fall (FLMNH-EA 01610169). These data suggest that fishing occurred during all four seasons (fig. 4.8B, D).

The McQueen Shell Ring

Two hardhead catfishes and five Atlantic croakers were analyzed for δ18O[otolith] profiles. All otoliths from the McQueen Shell Ring yielded seasonal results (table 4.3). One hardhead catfish was captured during spring (GMNH 02420216), while the other was captured during fall (GMNH 02420047). Two Atlantic croakers were captured in winter (GMNH 02420227 and 02420261), two were captured in spring (GMNH 02420057 and 02420100), and one was captured in summer (GMNH 02420187). These data suggest that people fished during all four seasons.

The St. Catherines Shell Ring

I sampled 16 hardhead catfish otoliths and nine Atlantic croaker otoliths from the St. Catherines Shell Ring for isotopic analysis (table 4.3). Sixteen of the archaeological δ18O[otolith] yielded profiles that provide evidence of season of capture. One δ18O[otolith] from a hardhead catfish indicates that people captured this fish during winter (GMNH 02381373), four hardhead catfish (GMNH 02380115, 02381373, and two otoliths from 02380118) were captured in spring, and two were captured in fall (two otoliths from GMNH 02381373). δ18O[otolith] from archaeological Atlantic croakers (fig. 4.8C) indicate that people captured one individual in winter (GMNH 02381348), two in spring (GMNH 02381477 and 02381554), four in summer (GMNH two from 02381444, and one each from 02380999 and 02381886), and two were captured in fall (GMNH 02381203 and 02381516). These data suggest that people fished during all four seasons.

Summary

δ18O[otolith] profiles of archaeological specimens indicate that people fished during all four seasons at the West, McQueen, and St. Catherines shell rings. The limited sample from the Cannon’s Point Ring prevents a comprehensive understanding of seasonal fishing behaviors at this site.

TABLE 4.3: Archaeological Otolith Estimated Season of Capture

δ18O ‰(VPDB)

Catalog no.

Ring

Species

Otolith no.

One before terminal

Terminal

Estimated season captured

FLMNH-EA 01551061

Cannon’s Point

A. felis

Cannon’s-1

−0.93

—

Indeterminate

FLMNH-EA 01550585

Cannon’s Point

M. undulatus

Cannon’s-3

0.47

1.28

Cold

FLMNH-EA 01610027

West

A. felis

West-1

−0.70

−0.70

Warm/cold transition

FLMNH-EA 01610161

West

A. felis

West-2

−0.44

−0.96

Warm

FLMNH-EA 01610169

West

M. undulatus

West-3

−1.90

−1.28

Warm/cold transition

FLMNH-EA 01610169

West

M. undulatus

West-4

−0.30

1.51

Cold

FLMNH-EA 01610194

West

M. undulatus

West-5

−0.39

1.19

Cold

FLMNH-EA 01610214

West

M. undulatus

West-8

0.21

−0.71

Cold/warm transition

FLMNH-EA 01610214

West

M. undulatus

West-9

−0.14

1.12

Cold

FLMNH-EA 01610231

West

M. undulatus

West-10

0.84

0.62

Indeterminate

GMNH 02420216

McQueen

A. felis

McQueen-1

−0.31

−0.43

Cold/warm transition

GMNH 02420047

McQueen

A. felis

McQueen-3

−0.86

−0.68

Warm/cold transition

GMNH 02420227

McQueen

M. undulatus

McQueen-2

1.05

0.31

Cold

GMNH 02420187

McQueen

M. undulatus

McQueen-4

−1.52

−1.62

Warm

GMNH 02420261

McQueen

M. undulatus

McQueen-5

−0.75

0.69

Cold

GMNH 02420057

McQueen

M. undulatus

McQueen-6

0.28

−0.81

Cold/warm transition

GMNH 02420100

McQueen

M. undulatus

McQueen-7

0.51

−0.45

Cold/warm transition

GMNH 02380115

St. Catherines

A. felis

0115-O1

−0.73

−0.54

Indeterminate

GMNH 02380115

St. Catherines

A. felis

0115-O2

−0.39

−0.95

Cold/warm transition

GMNH 02380118

St. Catherines

A. felis

0118-O3

−0.69

−0.76

Cold/warm transition

GMNH 02380118

St. Catherines

A. felis

0118-O4

−1.39

—

Indeterminate

GMNH 02380118

St. Catherines

A. felis

0118-O5

−0.59

−0.46

Indeterminate

GMNH 02380118

St. Catherines

A. felis

0118-O6

0.02

−1.01

Cold/warm transition

GMNH 02380122

St. Catherines

A. felis

0122-O7

−0.66

—

Indeterminate

GMNH 02380120

St. Catherines

A. felis

0120-O8

0.06

—

Indeterminate

GMNH 02381373

St. Catherines

A. felis

1373-O4

−0.14

−0.18

Warm/cold transition

TABLE 4.3 — (Continued)

δ18O ‰(VPDB)

Catalog no.

Ring

Species

Otolith no.

One before terminal

Terminal

Estimated season captured

GMNH 02381373

St. Catherines

A. felis

1373-O5

−0.28

−0.33

Cold/warm transition

GMNH 02381373

St. Catherines

A. felis

1373-O6

−0.30

−0.28

Warm/cold transition

GMNH 02381373

St. Catherines

A. felis

1373-O7

0.12

0.40

Cold

GMNH 02381437

St. Catherines

A. felis

1437-O8

—

−0.08

Indeterminate

GMNH 02380494

St. Catherines

A. felis

0494-O14

−0.67

—

Indeterminate

GMNH 02380989

St. Catherines

A. felis

0989-O17

−0.23

—

Indeterminate

GMNH 02381037

St. Catherines

A. felis

1037-O19

—

−1.11

Indeterminate

GMNH 02381348

St. Catherines

M. undulatus

1348-O3

−0.17

0.32

Cold

GMNH 02381444

St. Catherines

M. undulatus

1444-O9

−1.97

−1.90

Warm

GMNH 02381444

St. Catherines

M. undulatus

1444-O10

−0.53

−1.07

Warm

GMNH 02381477

St. Catherines

M. undulatus

1477-O11

−0.81

−0.74

Cold/warm transition

GMNH 02381516

St. Catherines

M. undulatus

1516-O12

−1.34

−0.75

Warm/cold transition

GMNH 02381554

St. Catherines

M. undulatus

1554-O13

0.63

−0.74

Cold/warm transition

GMNH 02380999

St. Catherines

M. undulatus

0999-O21

−1.07

−1.28

Warm

GMNH 02381203

St. Catherines

M. undulatus

1203-O25

−1.41

−0.08

Warm/cold transition

GMNH 02381886

St. Catherines

M. undulatus

1886-O26

−1.74

−2.67

Warm

δ18O[otolith], ESTUARINE ENVIRONMENTS, AND ARCHAEOLOGICAL IMPLICATIONS

Modern δ18O[otolith] Problems and Areas of Future Research

In most cases, modern δ18O[otolith] accurately determined the season in which the fish died, however, there are some problems.

Shackleton (1973) outlines six requirements for a successful archaeological application of δ18Ocarbonate to determine season of capture. To paraphrase Shackleton’s requirements, he notes that: (a) the species must form their carbonate structure in isotopic equilibrium with the ambient water; (b) the isotopic composition of the water in which the carbonate structure forms must remain constant through a season; (c) the water temperature in which the carbonate structure forms must be sea temperature; (d) the organism must deposit the carbonate structure throughout the year; (e) growth in the carbonate structure must be great enough to allow for discrete sampling of increments covering no more than a few weeks; and (f) the habitat in which the organism lives must undergo large and regular seasonal temperature oscillations. Although hardhead catfish and Atlantic croaker otoliths meet requirements a, c, and f, otoliths from these two species do not meet requirements b, d, and e. This may explain why some of the modern δ18O[otolith] did not indicate the correct season of capture.

Firstly, δ18O[water] in which the fish lives does not remain constant through the season (Shackleton, 1973: requirement b). It is clear from the zooarchaeological record of the Georgia coast that estuarine fishes were an important subsistence resource (Reitz, Quitmyer, and Marrinan, 2009; Colaninno, 2010; Reitz et al., 2010: 54–57). People fished estuarine fishes heavily, but they did not fish in offshore areas where δ18O[water] values are more stable. To characterize seasonal fishing efforts in inshore settings, this requirement must be met. It is possible that a more comprehensive environmental understanding of Georgia estuaries can generate accurate δ18O[otolith] models that account for temperature, salinity, and δ18O[water] (see Surge and Walker, 2005; Andrus and Crowe, 2008; Culleton, Kennett, and Jones, 2009). Monthly analysis of δ18O[water] in conjunction with δ18O[otolith] from several locations surrounding St. Catherines Island may resolve this issue.

Fishes are mobile animals and movement of fishes confounds fluctuations in δ18O[water], again violating Shackleton’s (1973) requirement b. Both hardhead catfishes and Atlantic croakers move within estuaries and outside estuaries (Dahlberg, 1972; Muncy and Wingo, 1983; Hare and Able, 2007). Fish movement complicates documenting environmental oscillations within Georgia estuaries. Each individual fish may experience different environmental parameters with movement. Alternatively, these species may have a specific set of preferred environmental conditions, including temperature and salinity, within which the fish swims as these parameters move with tides and seasons. This behavior, known as thermoregulatory movement, is documented in other fish species (Jones and Campana, 2009) and could be practiced by hardhead catfishes and Atlantic croakers. Developing better models to predict δ18O[otolith] through further study of δ18O[water], temperature, and salinity may resolve some of the confounding factors of temperature and salinity fluctuations on δ18O[water], but seasonal temperature oscillations will be difficult to detect in fishes with thermoregulatory movement.

Shackleton (1973: requirement d) also notes that formation of the carbonate structure used to determine seasonality must form throughout the year. Growth in fish otoliths may violate this requirement. Researchers note stoppage of otolith growth in other fish species (Fowler, 1995) and this could occur in hardhead catfishes and Atlantic croakers. This is particularly likely for hardhead catfishes. Males of this species gestate their eggs and young in their mouth for approximately 60 to 80 days after spawning (Dahlberg, 1972). Oral gestation occurs during the late spring through early fall (Gunter, 1947; Ward, 1957). During this period, males do not eat and somatic growth may not occur. The fact that only one archaeological hardhead catfish otolith had a terminal increment that formed in summer further suggests that otolith growth is not continuous throughout the year. Hardhead catfish are most abundant in Georgia estuaries during summer (Dahlberg, 1972), making the limited evidence for summer-captured hardhead catfish surprising. Nonetheless, modern hardhead catfish δ18O[otolith] generally do form otolith increments in warmer months. Additional modern sampling of both males and females, in known states of reproduction, is required to understand consequences of reproduction on somatic growth and otolith formation.

Shackleton (1973: requirement e) also observes that growth rates of the carbonate structure must be large enough to sample isolated increments covering no more than a few weeks of growth. Some archaeological otoliths do not meet this requirement, particularly otoliths from older fishes. This problem is noted when peaks in δ18O[otolith] profiles are examined in conjunction with the number of incremental bands in each otolith. Theoretically, fish form growth bands through ontogeny in response to environmental and biological conditions such as temperature, food availability, and reproductive efforts (Pannella, 1971, 1980; Wootton, 1998: 111–116; Van Neer, Löugas, and Rijnsdorp, 2004). Major fluctuations in environmental and biological conditions that the fish experiences generally occur annually, causing fish to grow quickly and then slowly within an annual cycle. This process produces two visually distinct bands per year (dark and light growth bands). As such, the number of bands in an otolith should correlate to the number of isotopic peaks in δ18O[otolith] profile when plotted through ontogeny (figs. 4.7, 8A–D, and 9). This is not always the case, however. In some otoliths, the number of increments is equal to the number of seasonal peaks in the δ18O[otolith] profile. In other otoliths, there are more increments than peaks. This suggests that either too little growth occurred in these otoliths to discretely sample each season using the sampling method I employed, or increment formation does not correlate to seasonal temperature oscillations in every case.

The effect of growth increments that cover no more than a few weeks also is seen in FLMNH-EA 01610231 (fig. 4.9). This individual was 18.5 ontogenic years at death and formed 1.07 mm of noncore otolith (from the terminal edge of the otolith to the outer edge of the core). Assuming an average growth rate over the 17.5 years of noncore growth, only 0.06 mm of otolith formation occurred per year or 0.01 mm every three months (i.e., per season). I spaced isotopic drilling paths for both modern and archaeological otoliths between 0.1 and 0.2 mm apart. It is impossible to isolate season of capture for older individuals with such little growth each season. Because fish generally grow most rapidly during their first few years of life (Wootton, 1998: 116), otoliths from younger individuals should provide higher-resolution trends in temperature oscillations experienced by the fish.

Researchers also use visual characterization of the terminal band type of otoliths to determine seasonality. If the type of banding, that is dark or light bands, is known to occur during specific seasons for a species, the terminal band can be used to infer the season in which the fish was captured (Smith, 1983; Hales and Reitz, 1992; Erlandson, 1994: 103; Higham and Horn, 2000). Currently, this method yielded inconclusive results for both hardhead catfishes and Atlantic croakers. For modern hardhead catfishes, individuals were captured only during five months of the year (May, June, July, August, and September), representing two seasons: spring and summer. All hardhead catfishes in the sample had dark or fast, terminal growth bands when they were captured. Although this indicates that hardhead catfish likely form dark growth bands in the spring and summer, these data do not indicate whether dark growth occurs continuously throughout the spring and summer and when light growth bands form. Season of death for Atlantic croakers in the modern sample includes croakers that died in spring and summer. Only one croaker captured in spring was in noncore growth and this individual was forming a dark growth band. Otoliths from Atlantic croakers captured in summer had both dark and light growth terminal bands. One otolith was in light growth formation and four were in dark growth formation. These data indicate that dark bands generally form during spring and summer; however, without direct evidence that light bands occur in winter and fall, it is impossible to draw this conclusion.

Characterizing the terminal band in otoliths may provide an additional method to determine season of capture, but more modern sampling is needed to understand seasonal timing of band formation in these two species. Overall results from the modern δ18O[otolith] indicate that oscillations in δ18O[otolith] can estimate temperature oscillations fishes experienced just prior to and at death and thus, season of capture. Further research is needed to understand the full seasonal range of environmental oscillations, particularly correlations among temperature, salinity, and δ18O[water] in Georgia estuaries, and biological and environmental factors that affect otolith growth and incremental banding in these two species.

Archaeological Implications

Researchers have conducted analyses of clam and oyster incremental formation and δ18O profiles at several Late Archaic shell rings, including the shell rings in this otolith study (Quitmyer, Hale, and Jones, 1985; O’Brien and Thomas, 2008; Thompson and Andrus, 2011). These mollusc studies concluded that people harvested shellfish during multiple seasons (Marrinan, 1975: 99; Thompson and Andrus, 2011), and in some instances, throughout the year (Quitmyer, Hale, and Jones, 1985; Thompson, 2006; Thomas, 2008: 927; Thompson and Andrus, 2011). These data suggest a model of year-round shellfish harvesting at most, although not necessarily at all, shell rings (Thompson and Andrus, 2011).

This archaeological δ18O[otolith] study also suggests a year-round model for fishing. At the West, McQueen, and St. Catherines shell rings, δ18O[otolith] profiles just prior to and at death indicate that people captured these two fish species during all four seasons in conjunction with multiseason harvesting of shellfishes (table 4.3). Researchers in other coastal areas document a similar pattern of year-round resource use by coastal peoples in the past (Yesner, 1980; Russo, 1998; Keene, 2004; Orr, 2007).

Although δ18O[otolith] profiles define a pattern of year-round fishing at the West, McQueen, and St. Catherines shell rings, this does not mean the entire population associated with each shell ring lived there continuously. Segments of the population could be absent occasionally on collecting and hunting trips, social visits, or ritual activities for longer or shorter lengths of time. Such seasonal patterns of movement by only segments of a population are documented among modern hunter-gatherer populations (Meehan, 1982: 31–41; Kelly, Poyer, and Tucker, 2005) and likely characterize the behavior of archaeological populations.

Admittedly, evidence that people fished Georgia estuaries and deposited the fish remain at these shell rings during all four seasons does not directly equate to a year-round, sedentary population occupying shell rings. Temperature regimes at time of capture represent a discrete time interval during a period of three to four months. Archaeological δ18O[otolith] profiles are not sufficiently precise to identify patterned, but brief, absences or presences of fishing activities. It is possible that people only fished and deposited fish remains at these shell rings for a day, week, or month of the three to four month period defined using archaeological δ18O[otolith]. Given the large quantity of faunal remains (Colaninno, 2010), depth of deposits at these sites, and the multiseason harvesting practices documented in mollusc samples (Quitmyer, Hale, and Jones, 1985; O’Brien and Thomas, 2008; Thompson and Andrus, 2011), an extended, year-round occupation is probable.

SUMMARY AND CONCLUSIONS

This study is one of the first to use archaeological fish otoliths to determine the seasonality of fishing in the southeastern United States (for seasonal studies that used otoliths in other regions see, Erlandson, 1994: 103; Van Neer, Löugas, and Rijnsdorp, 1999; Van Neer et al., 2004; Hufthammer et al., 2010). Although initial results of this analysis are promising, further research is needed. Factors that control δ18O[otolith] for Georgia estuaries, as well as biological and environmental factors that control otolith formation must be better understood. Despite these shortcomings, modern δ18O[otolith] profiles indicate that δ18O[otolith] determines the season in which people captured the fish in most cases.

These data indicate that people fished hardhead catfishes and Atlantic croakers during multiple seasons. At the West, McQueen, and St. Catherines shell rings, people fished during all four seasons. With these data, future archaeological research can focus on patterns in the horizontal and vertical distributions of seasonal deposits within each shell ring and across the region, as well as other spatial, temporal, and behavioral scales. Additionally, seasonal data from molluscs can be examined in conjunction with data from fish otoliths to view seasonal resource use involving several taxa (Walker and Surge, 2006). Multiproxy studies may provide a better prospective on Late Archaic seasonal resource use patterns and settlement patterns than single-proxy studies.

CHAPTER 5: LATE PREHISTORIC SETTLEMENT PATTERNS: ZOOARCHAEOLOGICAL EVIDENCE FROM BACK CREEK VILLAGE, ST. CATHERINES ISLAND

Sarah G. Bergh[16]

Despite more than three decades of archaeological research on St. Catherines Island, there are still questions about the residential mobility of late prehistoric populations. Ethnohistoric accounts of late 16th-century coastal Georgia societies are open to interpretation; some researchers posit that the Guale people moved residences on a seasonal basis following available resources, while others suggest Guale lived in dispersed but permanent settlements. This debate also applies to the late prehistoric period (a.d. 1300–1580), when it is assumed Guale or their direct ancestors occupied the coast. This chapter presents the results of zooarchaeological analysis of recently excavated materials from Back Creek Village, a large, late prehistoric site on St. Catherines Island. These data are applied to the “Guale Problem” (Thomas, chap. 1, this volume), and provide new insight, as the materials were fine-screened, recovered from multiple middens at a single site, and yield a large sample of vertebrate remains and multiple seasonal indicators that speak to seasonality of site occupation.

SEASONALITY IN FAUNAL ASSEMBLAGES

Zooarchaeological remains are often used to address seasonal occupation of sites (Monks, 1981). Life histories of many animal species involve behavioral and physiological events that occur in response to seasonal changes in temperatures, vegetation, sunlight, and rainfall, among other factors. These phenological events are often visible in the archaeological record. Some species follow seasonal rounds, occupying estuarine waters only during certain seasons. Sea turtles, for example, spend most of the year offshore, but females lay their eggs on the beaches during the summer months. Sharks, too, tend to stay offshore except for the warmer months when they enter estuaries and nearshore waters. Some migratory birds stop along the Georgia coast in the spring and fall to rest and refuel. Reproductive cycles of many species are driven by seasonal events. The white-tailed deer (Odocoileus virginianus) breeding season is generally October–January and young are born in May and June. Fishes have specific spawning seasons, which vary by species. Fish of the same species born in the same year form a cohort, and each age cohort may have different food and habitat preferences. The location of preferred habitats and food may change on a seasonal basis, causing cohorts to move to different parts of the estuary or out of the estuary. Mollusc growth is mostly dependent on environmental conditions, such as temperature and salinity, and these often change on a seasonal basis. All these phenological events can be used to interpret the season in which an animal in the archaeological record died. It is important to remember, however, that there will always be individual variation and that the environmental conditions that trigger phenological events may not always occur on a regular, seasonal schedule—storms and unusually warm, cold, wet, or dry seasons can alter animal behavior and physiology.

The assumptions that follow the interpretation of an archaeological animal’s season of death—that humans killed the animal, the animal’s remains were deposited at the site about the time the animal was killed, and the site was therefore occupied by humans about the time the animal was killed—can be disputed in some cases. On St. Catherines Island, however, some evidence supports these assumptions. Abundant cultural material throughout the middens reported here supports the assumption that humans killed the animals and deposited the remains. Although a more tenuous assumption, the bones and shells deposited at most sites were likely collected and deposited while people occupied the site. Although storage of meat is certainly possible, it is less likely that meat was stored on the bone or shell and transported among sites on a regular basis. The bones and shells are heavy and bulky and the same animals are available in most other locations along the coast. It is important to remember, however, that the presence of animals killed in all seasons does not necessarily mean that the site was occupied permanently throughout the year; it is possible that the site was reoccupied intermittently over the course of a single or multiple years. The absence of animals killed in a season also is not necessarily evidence that the site was abandoned during that season, only that the archaeological excavations failed to unearth any animals that definitely died in that season. It is only possible to estimate season of death for a small portion of the individuals recovered at a site.

THE ‘GUALE PROBLEM’

The “Guale Problem” essentially sets up two different models, defined by economic potential and residential mobility (Thomas, 2008: 239). This chapter does not address economic potential, in terms of maize production, as there is no quantified study of botanicals from the late prehistoric period on St. Catherines. One maize kernel was found at Back Creek Village, the site discussed in this chapter, so the plant was utilized to some extent during the late prehistoric period by the people who lived at the site (Ruhl, 2008). The faunal evidence, instead, speaks to patterns of residential mobility. The model proposed by Larson (1980: 206–209, 221–228) and Crook (1986: 11–28), based on their interpretation of Jesuit missionary accounts for the region, suggests a residentially mobile society that was unable to support permanent settlements with maize grown on small patches of poor agricultural soils. The maize harvest in late summer allowed the population to aggregate for a time in towns, but throughout the rest of the year, households dispersed into small sets of households (i.e., matrilineages), moving residences seasonally among habitats with the most productive resources—oak forests in the fall to collect mast and hunt deer, marshside in the winter to collect molluscs, and near swidden plots in the spring for planting maize (Crook, 1986: 18). The model proposed by Jones (1978: 190–194), based on his interpretation of Jesuit accounts as exaggerated and other descriptions of southeastern Indians, suggests that Guale lived in dispersed, permanent settlements, each of which had access to mast and shellfish resources without the need for seasonal, residential mobility. In addition, although Jones also understood Guale to use a swidden system of maize cultivation, he proposed that maize plots were scattered around the settlement, new fields being cleared in the vicinity when necessary, without moving to a new site.

This debate about the Guale settlement-subsistence system also applies to the late prehistoric period, as it is assumed that Guale or their direct ancestors inhabited the coast at this time. A better understanding of the late prehistoric settlement-subsistence system may, therefore, shed light on the “Guale Problem.” The 1970s transect survey of the island addressed settlement-subsistence systems on an island-wide scale (Thomas, 2008). Sites, in general, and large sites in particular, are more numerous during the late prehistoric period than earlier (Thomas, 2008: 877), suggesting larger communities, and more of them. The sites tend to be located at the margins of marsh and forest habitats (Thomas 2008: 929–933). This would seem to support the Jones model. Faunal samples, however, were small, not fine-screened, and the samples of seasonal indicators from each site were also small (Reitz, 2008: 617, 656–663). The data generated by the survey were appropriate for addressing macroscale questions, but not for site-level questions about intrasite variability in subsistence and seasonality. The recent excavations at Back Creek Village were designed to address these site-level questions. Fine-screened faunal collections and the resulting large samples of vertebrates and clams from multiple middens from Back Creek are used to address the question of whether late prehistoric sites were occupied on a seasonal basis for the purpose of exploiting seasonally available resources, or if they were occupied on a permanent basis. The latter scenario allows for the movement of groups of people for subsistence, political, or social activities, but not residential movement of entire communities on a seasonal basis.

MATERIALS AND METHODS

Back Creek Village (9Li207) is located on the seaward side of the island, just inland from the marsh formed by McQueen Inlet (fig. 5.1). Thomas (2008: 520, 534) classified the site as large, defined as having an inferred subsurface area greater than 500 m². Numerous discrete shell middens are visible, and others have been located through a probe survey. The middens surround a large depression that was possibly man-made and may once have held water. Middens vary in size—most are several meters in diameter, though others are more amorphous and cover a larger area. The site was identified during the 1970s transect survey of the island and five middens were tested (Thomas, 2008: 584). In the 1990s, another midden was tested. The materials recovered in those excavations indicate that the site was occupied during the Irene phase (a.d. 1300–1580). Excavations in 2008 retested five of the previously excavated middens as well as two additional middens, one of which was a large, amorphous mound (fig. 5.2). Two one-by-one meter units were excavated into each of the seven middens. The tested middens were given the letter designations A–H, though E was not excavated in 2008. Deposits were water screened through nested screens, 1⁄8 inch mesh being the smallest. Vertebrate remains were sorted in the field and sent to the Zooarchaeology Laboratory, Georgia Museum of Natural History, University of Georgia, for analysis. All whole hard clam valves (Mercenaria spp.) also were retained for analysis.

Identification of the vertebrate remains and clam valves used the comparative collection of the Georgia Museum of Natural History, following standards established in Reitz and Wing (2008: 151–181). Specimens were counted and weighed to aid in establishing relative abundances of taxa. Fish otoliths and atlases were measured using lab standards; namely, greatest width for atlases, and greatest length, greatest width, and thickness for otoliths. Age estimates for deer were based on epiphyseal fusion and tooth eruption. Sex was not evaluated, as none of the elements appropriate for such designation were present in the sample.

NISP (number of identified specimens), MNI (minimum number of individuals), and biomass were estimated for each midden. MNI, based on symmetry and age, was estimated for the lowest taxonomic level possible, usually at the species or genus level, except in cases where more individuals were present at the family level. NISP assumes that each specimen is from a different animal, which overestimates the contribution of taxa that have large numbers of elements or particularly identifiable elements. MNI assumes that the entire animal was present at the site and tends to overemphasize the relative importance of small species since it gives equal weight to all species, though small species have less meat to contribute to the diet (Reitz and Wing, 2008: 212–213). Biomass was estimated from specimen weight using allometric formulas published in Reitz and Wing (2008: 68). This measure is based on the allometric principle that skeletal weight scales to body size as an animal gets larger, and may be a more accurate reflection of dietary contribution because it only assumes the presence at the site of the bones found, and estimates meat contribution from those elements (Reitz and Wing, 2008: 239). It must be noted, however, that skeletal weight is subject to diagenic processes, so specimen weight does not necessarily reflect the weight of the specimen when the animal was alive.

Data were further summarized in a number of ways. They were assigned to higher taxonomic categories based largely on class and order; this summary was done at the site level, merging the data for each midden. Richness, diversity, and equitability were estimated for each midden and for the site as a whole. Richness is the number of species present in the species list, not including commensals (Anura, Caudata, Lacertilia, Soricidae, Talpidae, Sigmodontinae). Diversity, using the Shannon-Weaver index, is an index of the relative contribution of each species to the overall diet and equitability measures the degree of evenness with which the species were used (Reitz and Wing, 2008: 110–113). The diversity index ranges from 0 to 5 and is calculated using the formula: H’ = –Σ (p[i]) (log[e]p[i]), where p[i] is the relative abundance of each taxon, in this case MNI and biomass estimated from specimen weight. The equitability index ranges from 0 to 1 and is calculated using the formula: V’ = H’/log[e]S where S is the number of taxa for which MNI and biomass were estimated.

Hard clams grow incrementally throughout the year by adding carbonate to the margins of each valve. In southeastern populations, an annual cycle is represented by a translucent, slow growth increment laid down in the summer and an opaque, fast growth increment laid down in the late winter–spring (Quitmyer, Jones, and Arnold, 1997). Using an established six-part sequence of growth (Jones, 1980; Quitmyer, Jones, and Arnold, 1985; Quitmyer, Jones, and Arnold, 1997; Quitmyer and Jones, chap. 7, this volume) and modern seasonal growth patterns (Quitmyer, Jones, and Arnold, 1997; Andrus and Crowe, 2008; O’Brien and Thomas, 2008; Quitmyer and Jones, chap. 7), it is possible to estimate season of death for the clams recovered at Back Creek Village. Andrus and Crowe (2008: 507–517) found that opaque growth began around November or December in St. Catherines clams and translucent growth began around March. Growth is most influenced by temperature, though other environmental variables, such as salinity, dissolved oxygen, and food availability, can cause variations in growth patterns (Andrus and Crowe, 2008: 499–502). In addition, there are physiological conditions that cause variations in this pattern—most specifically, older individuals lay down much thinner increments and may be more sensitive to environmental stresses (Andrus and Crowe, 2008: 499). Looking at multiple clams from a single context can help account for individual variation within an archaeological population.

Seventy-five percent of the left valves from each unit were selected for analysis using a random number table. In units with 10 or fewer left valves, all left valves were selected. Each valve was sectioned radially from the umbo to the edge, along the margin of greatest growth, with a Buehler Isomet low-speed saw. Thick sections were visually inspected to determine the final growth phase. Histograms comparing the percentage of specimens assigned to each growth phase were constructed for each unit and for the site as a whole, to illustrate the range and distribution of growth phases present in each context

Fish size estimation can be useful for determining season of death in two ways. Modern trawl data record the frequency of different size classes of fishes caught on a monthly basis. The size of archaeological fishes can then be compared to the modern data to estimate the time of year the fishes were captured. Trawl data are available for a number of localities along the Georgia Coast (DEIS, 1978; Nelson et al., 1991) including the landward side of St. Catherines Island (Dahlberg, 1972). Back Creek Village, however, is located on the seaward side and the modern data may not be directly comparable. Fish size is generally related to fish age. If growth rates are known for the species in a region, then individuals can be classified as juveniles, subadults, or adults. This information can then be used to estimate seasonality for species in which different age cohorts have distinct seasonal movements within or out of the estuary.

Standard length for Back Creek Village fishes was reconstructed from allometric formulas (table 5.1) using measurements of otoliths and atlases. Growth of these elements scales allometrically with fish size. Modern comparative collections were used to generate regression formulas relating otolith length or width and atlas width to standard length that were applied to the archaeological measurements (Colaninno, personal commun.; Reitz and Wing, 2008: 68). Standard length was estimated for nine taxa: sea catfishes (Ariidae), mullets (Mugil spp.), silver perch (Bairdiella chrysoura), seatrout (Cynoscion spp.), spot (Leiostomus xanthurus), kingfish (Menticirrhus spp.), Atlantic croaker (Micropogonias undulatus), black drum (Pogonias cromis), and red drum (Sciaenops ocellatus). Standard length was estimated for the most common element of each taxon present in each unit.

TABLE 5.1: Fish Size Regression Formulas

Otolith Width (mm) to Standard Length (mm)

Taxon

N

Slope (b)

Y-intercept (log a)

r2

Ariidae

337

1.13

1.31

0.7

Bairdiella chrysoura

68

1.09

1.32

0.92

Otolith Length (mm) to Standard Length (mm)

Taxon

N

Slope (b)

Y-intercept (log a)

r2

Cynoscion spp.

94

1.27

0.94

0.95

Menticirrhus spp.

45

1.27

1.13

0.97

Micropogonias undulatus

65

1.19

1.06

0.95

Pogonias cromis, Sciaenops ocellatus

75

1.238

1.05

0.91

Leiostomus xanthurus

86

1.39

1.06

0.86

Atlas Width (mm) to Standard Length (mm)

Taxon

N

Slope (b)

Y-intercept (log a)

r2

Mugil spp.

55

0.852

1.803

0.96

Sciaenidae

152

0.61

1.93

0.65

Fig. 5.1. Location of Back Creek Village on St. Catherines Island, Georgia.

Fig. 5.2. Topographic map of Back Creek Village showing the location of the middens excavated in 2008.

RESULTS

A total of 14,881 vertebrate specimens were identified, for a total weight of 2049.296 g, and a total of 449 individuals. The results are presented by midden in tables 5.2 through 5.8. Hardhead catfish (Ariopsis felis), mullets, killifishes (Cyprinodontidae), snakes (Serpentes), rabbits (Sylvilagus spp.), and deer are 100% ubiquitous. Herrings and shad (Clupeidae), silver perch, sea-
trout, spots, red drums, flounders, mud turtles (Kinosternidae), diamondback terrapin (Malaclemys terrapin), birds (Aves), and raccoon (Procyon lotor) are present in over half the middens. Overall, fishes dominate the MNI (84%) and contribute a large portion of the biomass (37%) (table 5.9). Deer contribute the most biomass (43%), but only a small percentage of the MNI. Turtles and other wild mammals contribute more to the MNI than deer, though pond turtles are the only taxon besides fishes and deer to contribute a significant portion of the biomass. Birds and snakes contribute a small percentage of the MNI and biomass. Killifishes contribute the largest number of individuals to the fish MNI, though sea catfishes contribute the largest portion of the fish biomass. Drums make up the next largest portion of fish biomass, but sea catfishes, drums, and mullets contribute roughly similar numbers of individuals. Other fishes are not an insignificant portion of the MNI, but contribute little to the total biomass.

Richness, diversity, and equitability results are presented in figure 5.3. Richness for the whole site was 36, but for the middens it ranged from 14 in midden G to 26 in midden D, with a mean of 19. Diversity, estimated from MNI, ranged from 1.89 in midden F to 2.46 for midden D, and for the site as a whole, was 2.55. Diversity, estimated from biomass, ranged from 1.49 in midden F to 2.18 in midden C, and for the site as a whole, was 1.81. Equitability, estimated from MNI, was 0.71 for the site, and ranged from 0.68 in midden F to 0.85 in midden B. Equitability, estimated from biomass, was 0.5 for the site, and ranged from 0.48 in midden H to 0.81 in midden G.

A total of 331 clam valves were sectioned for this study, but the growth phase of the final increment could only be determined for 308 valves. All growth phases were represented (T1–T3 and O1–O3) in the observed final increments (fig. 5.4). For the site as a whole there is a normal distribution around O1 growth, and the percentage in each phase ranges from 10% to 23%, a relatively equal representation of each phase. A similar distribution is seen in middens C (N = 26) and G (N = 48). All growth phases are also present in middens D (N = 53) and A (N = 66), though these middens have a small spike in T2 growth and another in O1 or O2 growth. Midden F (N = 27) is dominated by O1 growth and T2 is absent, midden B (N = 43) is dominated by O2 growth and T2 is absent, and midden H (N = 39) is dominated by O2 though T1 growth and T2 is absent.

Fish size was estimated for a total of 155 fishes (fig. 5.5). Age was estimated using biological studies of growth rates and size and age at maturity for each taxon. Size was estimated for a total of 41 sea catfishes from seven middens. The size ranges from 137 mm to 403 mm, with an average of 260 mm. Based on modern data for sea catfishes, these are all at least in their second year of life, and most are probably mature adults (Muncy and Wingo, 1983). Size was estimated for a total of 62 mullets from six middens. The size ranges from 88 mm to 201 mm, with an average of 135 mm. These individuals are likely under three years of age, and not mature (Collins, 1985). Size was estimated for a total of 17 silver perch from five middens. The size ranges from 95 mm to 180 mm, with an average of 140 mm. No data are available to address age. Size was estimated for a total of 20 seatrout from five middens. The size ranges from 149 mm to 521 mm, with an average of 352 mm. Seatrout can reach 150 mm by the end of the first year, and even 200 mm, depending on the environment. These individuals probably range in age from one year to six years (Johnson and Seaman, 1986). Size was estimated for a total of five spots from two middens. The size ranges from 137 mm to 187 mm, with an average of 157 mm. Based on modern data, these individuals are likely in their second year, and most are probably not mature (Hales and Van Den Avyle, 1989). Size was estimated for a total of two kingfish from two middens. The standard lengths for these two individuals were 263 mm and 326 mm. There are no data available to address age, though based on growth rates for other drums, these are probably adults. Size was estimated for a total of five Atlantic croakers from three middens. The size range was 145 mm to 203 mm, with an average of 180 mm. These individuals are probably in their second year, and likely not yet mature (Lassuy, 1983). Size was estimated for one black drum. The standard length for this individual was 87 mm. This individual is a juvenile, probably about half a year old (Sutter, Waller, and McIlwain, 1986). Size was estimated for two red drums from two middens. The standard lengths for these two individuals were 378 mm and 400 mm. These individuals are likely mature adults (Reagan, 1985).

Fig. 5.3. Richness, diversity, and equitability estimates for Back Creek Village, presented for each midden and for the site as a whole.

Fig. 5.4. Relative frequencies of final growth phases for hard clams (Mercenaria spp.) from Back Creek Village, presented for the site as a whole (top left graph) and for each midden.

Fig. 5.5. Fish size estimates for selected fishes from Back Creek Village, presented for the site as a whole.

TABLE 5.2: Back Creek Village, Midden A: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

1185

—

—

18.951

0.356

Elops saurus

Ladyfish

10

1

1.3

0.082

0.004

Anguilla rostrata

American eel

2

1

1.3

0.050

0.003

Siluriformes

Catfishes

44

—

—

3.551

0.069

Ameiurus natalis

Yellow bullhead

1

1

1.3

0.039

0.001

Ariidae

Sea catfishes

17

—

—

7.012

0.131

Ariopsis felis

Hardhead catfish

27

1

1.3

4.051

0.046

Bagre marinus

Gafftopsail catfish

23

2

2.6

2.788

0.055

Mugil spp.

Mullets

480

10

12.8

7.427

0.171

Cyprinodontidae

Killifishes

152

16

20.5

1.207

0.041

Sciaenidae

Drums

83

—

—

3.645

0.104

Bairdiella chrysoura

Silver perch

1

1

1.3

0.006

0.001

Cynoscion spp.

Seatrout

241

15

19.2

25.374

0.559

Leiostomus xanthurus

Spot

1

1

1.3

0.050

0.004

Menticirrhus spp.

Kingfish

3

1

1.3

0.243

0.014

Micropogonias undulatus

Atlantic croaker

1

1

1.3

0.270

0.015

Sciaenops ocellatus

Red drum

2

1

1.3

0.376

0.019

Paralichthyidae

Flounders

8

1

1.3

0.485

0.015

Anura

Frogs and toads

37

—

—

0.656

—

Anaxyrus spp.

North American toads

10

2

2.6

0.301

—

Scaphiopus holbrookii

Eastern spadefoot toad

22

3

3.8

0.648

—

Rana sp.

Bullfrog

1

1

1.3

0.010

—

Caudata

Newts and salamanders

6

1

1.3

0.128

—

Testudines

Indeterminate turtles

150

—

—

27.224

0.362

Kinosternidae

Mud turtles

10

2

2.6

2.340

0.070

Emydidae

Pond turtles

15

—

—

13.957

0.227

Malaclemys terrapin

Diamondback terrapin

31

3

3.8

19.740

0.290

Lacertilia

Indeterminate lizards

14

4

5.1

0.136

—

Anolis carolinensis

Green anole

1

(2)

—

0.019

—

Serpentes

Indeterminate snakes

43

—

—

2.443

0.034

Nerodia spp.

Water snakes

14

1

1.3

2.262

0.031

Zenaida macroura

Mourning dove

1

1

1.3

0.052

0.001

Passeriformes

Perching birds

6

1

1.3

0.116

0.003

Mammalia

Indeterminate mammals

193

—

—

73.483

1.346

Scalopus aquaticus

Eastern mole

1

1

1.3

0.097

0.003

Sylvilagus spp.

Cottontail rabbit

4

1

1.3

0.703

0.019

Sigmodontinae

New World mice and rats

11

—

—

0.173

0.006

Sigmodon hispidus

Hispid cotton rat

1

1

1.3

0.040

0.001

Procyon lotor

Raccoon

2

1

1.3

4.153

0.096

Odocoileus virginianus

White-tailed deer

29

2

2.6

95.908

1.708

Vertebrata

Indeterminate vertebrates

—

—

—

52.786

—

Total

2883

78

100

372.982

5.805

TABLE 5.3: Back Creek Village, Midden B: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

389

—

—

5.899

0.139

Clupeidae

Herrings and shads

4

1

2.2

0.015

0.002

Siluriformes

Catfishes

152

—

—

9.453

0.171

Ariidae

Sea catfishes

51

7

15.6

47.294

0.789

Ariopsis felis

Hardhead catfish

7

(1)

—

0.903

0.018

Bagre marinus

Gafftopsail catfish

142

(4)

—

14.558

0.257

Mugil spp.

Mullets

45

2

4.4

0.644

0.024

Cyprinodontidae

Killifishes

49

9

20.0

0.385

0.016

Orthopristis chrysoptera

Pigfish

1

1

2.2

0.021

0.001

Pomatomus saltatrix

Bluefish

1

1

2.2

0.021

0.001

Sciaenidae

Drums

9

—

—

0.150

0.012

Bairdiella/Stellifer

Small drums

11

—

—

0.086

0.007

Bairdiella chrysoura

Silver perch

30

7

15.6

1.227

0.055

Micropogonias undulatus

Atlantic croaker

6

2

4.4

1.086

0.041

Pogonias cromis

Black drum

2

1

2.2

0.010

0.001

Sciaenops ocellatus

Red drum

1

1

2.2

0.672

0.029

Paralichthyidae

Flounders

1

1

2.2

0.014

0.001

Anura

Frogs and toads

25

—

—

0.369

—

Anaxyrus spp.

North American toads

7

2

4.4

0.189

—

Scaphiopus holbrookii

Eastern spadefoot toad

7

2

4.4

0.122

—

Caudata

Newts and salamanders

10

1

2.2

0.032

—

Testudines

Indeterminate turtles

66

—

—

7.042

0.146

Malaclemys terrapin

Diamondback terrapin

2

1

2.2

0.821

0.028

Lacertilia

Indeterminate lizards

18

2

4.4

0.123

—

Serpentes

Indeterminate snakes

59

1

2.2

0.645

0.009

Mammalia

Indeterminate mammals

13

—

—

4.837

0.116

Soricidae

Shrews

2

1

2.2

0.014

0.001

Sylvilagus sp.

Cottontail rabbit

1

1

2.2

0.158

0.005

Odocoileus virginianus

White-tailed deer

1

1

2.2

15.089

0.303

Vertebrata

Indeterminate vertebrates

—

—

—

18.308

—

Total

1112

45

100

130.187

2.172

TABLE 5.4: Back Creek Village, Midden C: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

453

—

—

5.701

0.138

Lepisosteus spp.

Gars

15

1

1.5

0.549

0.020

Cyprinidae

Carp and minnows

1

1

1.5

0.014

0.001

Siluriformes

Catfishes

71

—

—

2.836

0.056

Ariidae

Sea catfishes

7

—

—

5.095

0.096

Ariopsis felis

Hardhead catfish

46

4

6.2

5.146

0.097

Bagre marinus

Gafftopsail catfish

33

1

1.5

5.109

0.097

Mugil spp.

Mullets

297

10

15.4

4.038

0.103

Cyprinodontidae

Killifishes

225

22

33.8

1.734

0.051

Lagodon rhomboides

Pinfish

1

1

1.5

0.005

0.000

Sciaenidae

Drums

4

—

—

0.040

0.004

Bairdiella/Stellifer

Small drums

12

2

3.1

0.159

0.012

Bairdiella chrysoura

Silver perch

8

(1)

—

0.366

0.020

Cynoscion spp.

Seatrout

4

2

3.1

1.311

0.063

Leiostomus xanthurus

Spot

8

2

3.1

0.065

0.006

Paralichthyidae

Flounders

1

1

—

0.011

0.000

Anura

Frogs and toads

14

—

—

0.329

—

Anaxyrus spp.

North American toads

13

2

3.1

0.336

—

Scaphiopus holbrookii

Eastern spadefoot toad

13

3

4.6

0.276

—

Testudines

Indeterminate turtles

63

—

—

8.119

0.157

Malaclemys terrapin

Diamondback terrapin

3

1

1.5

3.420

0.089

Lacertilia

Indeterminate lizards

13

3

4.6

0.178

—

Serpentes

Indeterminate snakes

113

—

—

2.050

0.029

Nerodia spp.

Water snakes

2

1

1.5

0.027

0.000

Aves

Indeterminate birds

30

1

1.5

2.067

0.040

Passeriformes

Perching birds

1

1

1.5

0.010

0.000

Mammalia

Indeterminate mammals

75

—

—

30.351

0.640

Didelphis virginiana

Opossum

1

1

1.5

0.229

0.007

Sylvilagus spp.

Cottontail rabbits

2

1

1.5

0.562

0.016

Sciurus sp.

Squirrels

1

1

1.5

0.126

0.004

Sigmodontinae

New World mice and rats

3

1

1.5

0.023

0.001

Procyon lotor

Raccoon

3

1

1.5

0.553

0.017

Odocoileus virginianus

White-tailed deer

6

1

1.5

17.736

0.373

Vertebrata

Indeterminate vertebrates

—

—

—

26.206

—

Total

1542

65

100

124.777

2.138

TABLE 5.5: Back Creek Village, Midden D: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

1013

—

—

14.190

0.289

Lepisosteus spp.

Gars

3

1

1.1

0.141

0.006

Elops saurus

Ladyfish

1

1

1.1

0.010

0.001

Anguilla rostrata

American eel

4

1

1.1

0.051

0.003

Clupeidae

Herrings and shads

55

3

3.2

0.254

0.010

Siluriformes

Catfishes

150

—

—

9.428

0.174

Ariidae

Sea catfishes

147

—

—

16.646

0.296

Ariopsis felis

Hardhead catfish

165

11

11.6

31.425

0.543

Bagre marinus

Gafftopsail catfish

32

4

4.2

2.694

0.052

Opsanus sp.

Toadfish

1

1

1.1

0.023

0.001

Mugil spp.

Mullets

538

27

28.4

8.264

0.176

Belonidae

Needlefish

1

1

1.1

0.013

0.001

Cyprinodontidae

Killifishes

79

16

16.8

0.575

0.023

Carangidae

Jacks

1

1

1.1

0.033

0.002

Sciaenidae

Drums

13

—

—

0.540

0.029

Bairdiella/Stellifer

Small drums

2

—

—

0.020

0.002

Bairdiella chrysoura

Silver perch

10

3

3.2

0.418

0.025

Cynoscion spp.

Seatrout

4

1

1.1

0.071

0.006

Leiostomus xanthurus

Spot

13

3

3.2

0.095

0.008

Micropogonias undulatus

Atlantic croaker

3

1

1.1

0.449

0.026

Pogonias cromis

Black drum

3

1

1.1

0.066

0.005

Sciaenops ocellatus

Red drum

1

1

1.1

0.739

0.031

Paralichthyidae

Flounders

6

1

1.1

0.413

0.013

Anura

Frogs and toads

10

—

—

0.208

—

Scaphiopus holbrookii

Eastern spadefoot toad

8

1

1.1

0.172

—

Rana sp.

Bullfrog

1

1

1.1

0.033

—

Testudines

Indeterminate turtles

554

—

—

122.871

0.989

Kinosternidae

Mud and musk turtles

1

1

1.1

0.061

0.005

Emydidae

Pond turtles

50

—

—

33.127

0.413

Malaclemys terrapin

Diamondback terrapin

129

4

4.2

98.558

0.841

Lacertilia

Indeterminate lizards

3

1

1.1

0.067

—

Serpentes

Indeterminate snakes

46

—

—

0.487

0.006

Colubridae

Nonvenomous snakes

2

1

1.1

0.008

0.000

Viperidae

Venomous snakes

1

1

1.1

0.012

0.000

Aves

Indeterminate birds

3

1

1.1

0.666

0.015

Mammalia

Indeterminate mammals

82

—

—

41.056

0.795

Didelphis virginiana

Opossum

1

1

1.1

0.173

0.005

Scalopus aquaticus

Eastern mole

10

1

1.1

0.707

0.019

Sylvilagus sp.

Cottontail rabbit

1

1

1.1

0.124

0.004

Sigmodon hispidus

Hispid cotton rat

1

1

1.1

0.015

0.001

Procyon lotor

Raccoon

1

1

1.1

0.134

0.004

Odocoileus virginianus

White-tailed deer

21

1

1.1

78.322

1.384

Vertebrata

Indeterminate vertebrates

—

—

—

73.884

—

Total

3170

95

100

537.243

6.203

TABLE 5.6: Back Creek Village, Midden F: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

327

—

—

13.577

0.279

Lepisosteus sp.

Gars

1

1

1.6

0.126

0.005

Siluriformes

Catfishes

55

—

—

2.562

0.051

Ariidae

Sea catfishes

23

—

—

2.783

0.055

Ariopsis felis

Hardhead catfish

43

4

6.6

6.025

0.113

Bagre marinus

Gafftopsail catfish

2

1

1.6

0.227

0.005

Mugil spp.

Mullets

205

5

8.2

2.651

0.075

Cyprinodontidae

Killifishes

120

27

44.3

0.853

0.031

Sciaenidae

Drums

3

—

—

0.351

0.021

Cynoscion spp.

Seatrout

3

1

1.6

0.268

0.017

Pogonias cromis

Black drum

11

1

1.6

8.416

0.188

Sciaenops ocellatus

Red drum

3

1

1.6

0.371

0.019

Paralichthyidae

Flounders

1

1

1.6

0.058

0.002

Anura

Frogs and toads

44

—

—

1.108

—

Anaxyrus spp.

North American toads

28

4

6.6

0.200

—

Scaphiopus holbrookii

Eastern spadefoot toad

10

2

3.3

0.824

—

Testudines

Indeterminate turtles

201

—

—

40.414

0.474

Kinosternon spp.

Mud turtles

3

1

1.6

0.276

0.013

Emydidae

Pond turtles

6

—

—

16.480

0.244

Malaclemys terrapin

Diamondback terrapin

69

3

4.9

113.474

0.947

Lacertilia

Indeterminate lizards

30

1

1.6

0.426

—

Serpentes

Indeterminate snakes

52

—

—

1.758

0.024

Colubridae

Nonvenomous snakes

59

1

1.6

10.535

0.149

Aves

Indeterminate birds

1

—

—

0.165

0.004

Rallidae

Coots and rails

4

2

3.3

0.492

0.011

Passeriformes

Perching birds

1

1

1.6

0.018

0.001

Mammalia

Indeterminate mammals

90

—

—

66.578

1.232

Scalopus aquaticus

Eastern mole

16

1

1.6

0.730

0.020

Sylvilagus spp.

Cottontail rabbit

2

1

1.6

1.432

0.036

Sigmodontinae

New World mice and rats

1

1

1.6

0.006

0.000

Odocoileus virginianus

White-tailed deer

17

1

1.6

79.288

1.438

Vertebrata

Indeterminate vertebrates

—

—

—

66.438

—

Total

1431

61

100

438.91

5.454

TABLE 5.7: Back Creek Village, Midden G: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

1183

—

—

6.414

0.148

Clupeidae

Herrings and shads

1

1

2.6

0.006

0.001

Siluriformes

Catfishes

85

—

—

2.290

0.046

Ariidae

Sea catfishes

36

8

20.5

7.435

0.138

Ariopsis felis

Hardhead catfish

57

(4)

—

4.438

0.085

Mugil spp.

Mullets

191

5

12.8

2.872

0.078

Cyprinodontidae

Killifishes

68

11

28.2

0.483

0.019

Sciaenidae

Drums

1

—

—

0.020

0.002

Bairdiella chrysoura

Silver perch

2

1

2.6

0.038

0.003

Cynoscion spp.

Seatrout

6

2

5.1

1.970

0.091

Leiostomus xanthurus

Spot

3

1

2.6

0.050

0.005

Paralichthyidae

Flounders

2

1

2.6

0.305

0.009

Anura

Frogs and toads

15

—

—

0.405

—

Anaxyrus spp.

North American toads

5

1

2.6

0.157

—

Scaphiopus holbrookii

Eastern spadefoot tad

5

1

2.6

0.184

—

Testudines

Indeterminate turtles

26

—

—

2.548

0.073

Kinosternon spp.

Mud turtles

4

1

—

1.646

0.044

Emydidae

Pond turtles

2

—

—

0.373

0.016

Malaclemys terrapin

Diamondback terrapin

3

1

2.6

3.941

0.097

Lacertilia

Indeterminate lizards

6

1

2.6

0.035

—

Serpentes

Indeterminate snakes

32

1

2.6

0.743

0.010

Mammalia

Indeterminate mammals

43

—

—

19.952

0.406

Sylvilagus spp.

Cottontail rabbit

2

1

2.6

1.759

0.044

Procyon lotor

Raccoon

3

1

2.6

2.212

0.054

Odocoileus virginianus

White-tailed deer

1

1

2.6

4.910

0.110

Vertebrata

Indeterminate vertebrates

—

—

—

23.518

—

Total

1782

39

100

88.704

1.479

TABLE 5.8: Back Creek Village, Midden H: Species List

Taxa

NISP

MNI

% MNI

Weight (g)

Biomass (kg)

Actinopterygii

Indeterminate bony fishes

1022

—

—

17.898

0.332

Elops saurus

Ladyfish

1

1

1.5

0.005

0.000

Clupeidae

Herrings and shads

2

1

1.5

0.010

0.001

Siluriformes

Catfishes

397

—

—

1.248

0.251

Ariidae

Sea catfishes

203

—

—

11.269

0.202

Ariopsis felis

Hardhead catfish

309

11

16.7

39.689

0.666

Mugil spp.

Mullets

287

14

21.2

5.731

0.138

Cyprinodontidae

Killifishes

190

14

21.2

1.247

0.040

Archosaurgus probatocephalus

Sheepshead

4

1

1.5

0.618

0.010

Lagodon rhomboides

Pinfish

1

1

1.5

0.006

0.000

Sciaenidae

Drums

14

—

—

0.196

0.014

Bairdiella chrysoura

Silver perch

3

1

1.5

0.099

0.008

Cynoscion spp.

Seatrouts

23

2

3.0

2.074

0.087

Leiostomus xanthurus

Spot

5

1

1.5

0.055

0.006

Menticirrhus spp.

Kingfish

40

3

4.5

1.849

0.073

Paralichthyidae

Flounders

6

1

1.5

0.323

0.010

Anura

Frogs and toads

9

—

—

0.198

—

Anaxyrus spp.

North American toads

2

1

1.5

0.067

—

Scaphiopus holbrookii

Eastern spadefoot toad

3

2

3.0

0.040

—

Caudata

Newts and salamanders

3

1

1.5

0.011

—

Testudines

Indeterminate turtles

168

—

—

16.022

0.231

Kinosternidae

Mud and musk turtles

11

1

1.5

0.522

0.029

Malaclemys terrapin

Diamondback terrapin

48

2

3.0

42.325

0.444

Serpentes

Indeterminate snakes

79

—

—

1.504

0.021

Colubridae

Nonvenomous snakes

1

1

1.5

0.149

0.002

Mammalia

Indeterminate mammals

70

—

—

26.075

0.530

Soricidae

Shrews

9

1

1.5

0.247

0.007

Sylvilagus sp.

Cottontail rabbit

1

1

1.5

0.957

0.025

Sciurus spp.

Squirrels

3

1

1.5

1.084

0.028

Peromyscus spp.

Deer mice

20

2

3.0

0.377

0.011

Odocoileus virginianus

White-tailed deer

27

2

3.0

132.961

2.290

Vertebrata

Indeterminate vertebrates

—

—

—

51.637

—

Total

2961

66

100

356.493

5.457

TABLE 5.9: Back Creek Village: Summary

NISP

MNI

% MNI

Biomass (kg)

% Biomass

Deer

102

9

2.0

6.09

43.2

Other wild mammals

28

15

3.3

0.32

2.3

Birds

47

8

1.8

0.07

0.5

Snakes

503

8

1.8

0.32

2.3

Pond turtles

358

15

3.3

1.90

13.5

Mud turtles

29

6

1.3

0.09

0.6

Sea catfishes

1370

55

12.2

3.44

24.4

Mullets

2043

73

16.3

0.46

3.3

Killifishes

883

115

25.6

0.13

0.9

Drums

593

61

13.6

1.11

7.8

Other fishes

137

30

6.7

0.11

0.8

Commensal taxa(1)

467

54

12.0

0.07

0.5

Total

6560

449

100

14.11

100

(1)Biomass not calculated for frogs, toads, lizards, and salamanders.

DISCUSSION

The vertebrate taxa recovered from Back Creek Village are available year round in the estuary. Seasonally available resources, such as sea turtles, sharks, and migratory birds are completely absent. Terrestrial mammals, such as deer, raccoon, squirrels, opossums, and rabbits, live on the island, and although the mainland is close enough for some exchange between populations, there is no population-scale migration of these taxa off the island at any time of year. Modern studies of southeastern estuarine fishes demonstrate that the most common fish taxa from Back Creek—sea catfishes, mullets, killifishes, drums, and flounders—are present in the estuary throughout the year. The age cohorts and locations of each taxon may change, but the taxon itself is present all year some place in the estuary (Dahlberg, 1972; DEIS, 1978; Nelson et al., 1991). The less abundant fishes in the Back Creek collection are also available for at least most of the year. This suggests a subsistence strategy that targeted consistently available animal resources.

The subsistence strategy also appears to have been generalized, not focused on single taxa or habitats. Mammals, fishes, shellfishes, estuarine and mud turtles, and terrestrial and water birds are all found in the same middens. Richness varies among middens, but it roughly correlates with NISP for the midden, and the same common taxa are present in all or most middens. Diversity estimated from MNI is consistently higher than diversity estimated from biomass, suggesting that although a range of taxa were exploited in any given midden, a small number of these taxa contributed most of the meat to the diet. Equitability for MNI is quite high in all middens (over 0.68), indicating that the hunting strategy targeted a range of taxa on a relatively equal basis. Equitability estimated from biomass is lower in most cases because deer, the largest animal identified in the collection, dominates the biomass. In middens C and G, equitability is the same for MNI and biomass. In midden C, this is because both MNI and biomass are dominated by a single taxon (killifishes in the case of MNI and deer in the case of biomass), and in midden G, this appears to be because no taxa dominate the MNI or biomass. The variability among middens can probably be accounted for by the different sample sizes recovered and by the fact that the specific species caught on any given fishing or hunting trip will vary.

The fish size and age data suggest a focus on fishing during the warmer months, though size could only be estimated for a handful of the fish individuals present at the site and the modern data used to estimate age and seasonality are not precise. The size of the black drum individual from midden D suggests an age of about half a year. The black drum spawning season is in the late winter/early spring (Sutter, Waller, and McIlwain, 1986), which could suggest a late-summer or fall occupation for midden D, though juvenile black drums are present in the estuary year-round (Nelson et al., 1991). Size was estimated for sea catfishes at the family level, since otoliths of the two species can be very similar. The individuals at Back Creek are all probably over a year old. They are all within the size ranges of hardhead catfish captured during the summer in modern trawls (Dahlberg, 1972). Size was estimated for seatrout at the genus level, as otoliths and atlases can look very similar. However, most of the individuals are probably spotted seatrout (Cynoscion nebulosus), and all but one are probably over two years of age. Juveniles and adults of this species are present in the estuary year-round (Nelson et al., 1991). Adults of the other species, weakfish (Cynoscion regalis), are present from April to December, and juveniles are present all year. Although there are no age estimates for the silver perch, the size of individuals from middens B, C, and G are in the range, or larger, than those caught only in summer in modern trawls. The individuals in middens D and H are in the range caught all year (Dahlberg, 1972). The spots in midden G are in the range of those caught in the summer and fall in modern trawls, while those in midden G are into the range of those caught all year (Dahlberg, 1972). The size of the kingfish at Back Creek is larger than those caught in the modern trawls, but is closest to those caught in the fall and early winter (Dahlberg, 1972). The Atlantic croaker individuals from middens A, B, and D are in or above the size range captured during the summer and early fall (Dahlberg, 1972). Adult red drums, croakers, kingfish, and spots are present in the estuary at least from April to December (Nelson et al., 1991). Size was estimated for mullets at the genus level because the skeletal elements of the species found on the Georgia coast are very similar. The mullets ranged from under a year to two years. As striped mullet juveniles and adults are present in the estuary year-round (Dahlberg, 1972; Nelson et al., 1991), this does not provide any seasonal evidence. Back Creek is located on the seaward marsh, and the modern trawl data are from the landward marsh, so the comparability of the two data sets is uncertain. In addition, trawling as a method of capture may not replicate the methods or locations used by past human populations. The consistency among the middens and among the fish taxa, however, does suggest fishing was especially important during the warmer months.

The results from clam incremental analysis indicate that clams were collected during all seasons at Back Creek Village. The distribution of final increments for the site as a whole is relatively even, though weighted a little toward the cold season, with a peak at O1 growth. Middens C and G have a similar distribution. Middens A and D are equally weighted toward cold and warm season growth, with small peaks at T2 and O1 or O2 growth, also suggesting that clams were collected in all seasons. Midden F is dominated by O1 growth and may suggest more of a fall–winter collection. Midden B is dominated by O2 and O3 growth, and might represent more of a winter–spring collection. Midden H is missing only T2 growth and may be a fall–spring collection. In all cases, except for midden B, both cold and warm season growth are represented. This may suggest a focus on molluscs, such as clams, during the colder seasons when many other animals are lean or less abundant and plant materials are less abundant.

CONCLUSION

The zooarchaeological evidence is more consistent with the Jones model of settlement than with the Larson and Crook model. The late prehistoric subsistence strategy represented at Back Creek Village relied heavily on vertebrate resources that are present in the estuary throughout the year, suggesting that seasonal movement to exploit animal resources was not a structuring principle of the settlement system. The same suite of vertebrate resources is present in all middens and the seasonal indicators suggest that all middens were utilized during multiple seasons. Although this is not proof that people occupied the site on a permanent basis, there is no evidence they occupied it on a strictly seasonal basis. The middens themselves may represent contemporary households or different occupations by one, or a few, households over time, but they do not appear to be a series of seasonal occupations. Animal taxa in a temperate estuarine environment vary in their abundance and location on a variety of temporal scales. Daily tides, fluctuations in timing and strength of tides during the year, rainy or dry periods in the interior or on the coast, stormy times of year, and temperature changes all influence resource abundance. Different taxa are affected by and respond to these environmental changes differently. The Georgia coast, then, is not a place where seasonality of resource availability is simply a matter of fall, winter, spring, and summer. Subsistence-settlement systems, instead, exploited the constant changes in availability of each resource—focusing on taxa that are reliably present in the estuary and emphasizing those that are most abundant during a time of year, such as fishes in the summer and fall and invertebrates in the winter and spring.

[1] I gratefully acknowledge the assistance of Lorann Pendleton Thomas, Chelsea Graham, and Diana Rosenthal in preparing this manuscript.

[2] In 1562 and 1564, the French established two colonial forts (Charlesfort and Fort Caroline) at opposite ends of the central Georgia Bight. Each fort was occupied for about a year, and the subsequent Spanish towns of St. Augustine and especially Santa Elena—in roughly the same territory—continued an even more significant contact with local Indian populations after 1565. Following a brief period of Jesuit mission activity (in 1569–1570), the Franciscans launched a more concerted effort in 1574–1575. But Mocamo was not truly missionized until 1587, and the major Guale missions were established in 1595–1605 (Jones, 1978; Worth, 1998, 2004, 2007).

[3] The most important sources addressing the nature of Guale coastal adaptations include Swanton (1922, 1946), Sturtevant (1962), Larson (1969, 1978, 1980), Jones (1978), and Worth (2004, 2007); see also Bushnell (1990), Crook (1986), Jones (1873), Hann (1986a, 1986b), and Saunders (2000a, 2000b).

[4] By this interpretation, the Guale dispersed still further in the springtime into nuclear family settlements spread throughout the oak forest, located near swidden plots of maize, beans, and squash. In Crook’s “Annual Model” the Guale “resided in towns from the first part of July until the middle of September when they dispersed to gather nuts” (Crook 1986: 20), after which they once again dispersed, probably into a “matrilineage segment with four or five nuclear families forming the social core,” several related families living together in dispersed settlements located throughout the oak forest, subsisting on acorns, hickory nuts, and communal deer hunts, with occasional aggregation for feasting (Crook, 1986: 21). Fall settlements were basically chiefly compounds “defined by towns composed of temporary and changing populations, as opposed to the seasonally stable population of the summer towns.”

[5] Whereas Fr. Rogel reported that the Guale dispersed seasonally to gather acorns, Jones (1978: 193) questioned whether it was necessary to abandon the “dispersed town” in order to harvest the mast. With respect to shellfish, Jones notes that whereas some important Guale towns lay beyond the oyster beds, “there is no documentary evidence that [the Guale] spent seasonal periods downstream or along the inland waterways to exploit the oysters.” Citing Robert Sandford’s 1666 account for the North Edisto River (South Carolina), Jones suggests that concentrations of oysters were sufficiently close to the maize fields “that the beds could be exploited without seasonal shifts in residence” (Jones, 1978: 193).

[6] Specifically with regard to the island-wide survey sites, we also compared the existing ceramic and 14C chronologies for St. Catherines Island (Thomas, 2008: chap. 15). A total of 189 radiocarbon dates had been processed on archaeological samples from St. Catherines Island, and 110 of these dates—from 31 distinct mortuary and midden sites—were directly associated with datable ceramic assemblages from the aboriginal phase. This diverse sample of 14C dates, which spanned more than four millennia, provides a workable set of radiometric controls on the ceramic chronology currently available for St. Catherines Island. The results fine-tune, yet overwhelmingly, confirm the previous research on the ceramic chronology for Georgia’s north coast, particularly the work of Joseph Caldwell, Antonio Waring, and Chester DePratter.

[7] Some years ago, we reported the results of our excavations of several Refuge-Deptford-Wilmington burial mounds on St. Catherines Island (Thomas and Larsen, 1979). We analyzed 29 radiocarbon dates, nearly one-quarter of them processed on marine shell. Although aware of potential problems associated with radiocarbon dates on sea shells, we followed the lead of Joseph Caldwell, who had also worked on St. Catherines Island. Caldwell concluded that “radiocarbon determinations made from oyster shell do not appear to differ significantly from determinations made from charred wood” (Caldwell, 1971: 1). Today, we understand that this assumption was incorrect. A significant reservoir effect is operating here because, relative to the atmosphere, ocean water is depleted in 14C, transmitting this deficiency to marine organisms. This means that 14C determinations processed on marine samples will routinely appear to be older (in many cases, several centuries older) than 14C dates run on contemporary terrestrial samples. We found it necessary to derive a unique reservoir correction for St. Catherines Island and the results of this fieldwork and analysis are reported in Thomas (2008: chap. 13; see also Thomas, Sanger, and Hayes, n.d.).

[8] This apparent discrepancy arises because, in order to derive an accurate and reliable local reservoir correction, we processed a dozen radiocarbon dates on modern time prebomb samples.

[9] This study is reinforced by an oxygen isotope study of modern and ancient clams from St. Catherines Island (Andrus and Crowe, 2008).

[10] “To repeat: The available archaeological evidence does not permit the conclusion that Irene populations were sedentary (although we certainly believe that such was the case). But sticking to the documented archaeological specifics, the data regarding site seasonality are conclusive: (1) single-season sites are extremely rare during Irene times (as they are rare throughout the entire aboriginal period on St. Catherines Island) and (2) three-quarters of the known Irene components on St. Catherines Island were occupied during three or more seasons” (Thomas, 2008: 1098).

[11] “Patch types” reflect the way in which food resources were clumped or aggregated across the landscape (Thomas, 2008: 63). Specific “hunt types” are variously associated with one or more particular prey species, particular microhabitats (“patch type”), specialized methods of search or capture, specialized transport or foraging technology, and certain seasons or environmental conditions (Thomas, 2008: 71).

[12] On occasion, as at Little Camel New Ground Field 5 (9Li206), we did employ 1⁄16 in. screens to sample the extremely dense concentration of fish bones encountered (Thomas, 2008: 519). But ¼ in. hardware was primarily used in the island-wide survey. We note, parenthetically, that Rochelle Marrinan made extensive use of fine-mesh screens in 1973–1975, while excavating two Late Archaic shell rings on St. Simons Island (Marrinan, 1975, 2010). In this respect, she was considerably ahead of her time.

[13] In chapter 3 in this volume, E.J. Reitz, B. Saul, J.W. Moak, G.D. Carroll, and C.W. Lambert assess the value of the modern ichthyofaunal survey data as an archaeological proxy for St. Catherines Island.

[14] We gratefully acknowledge the long-term research support of the Edward John Noble Foundation and the St. Catherines Island Foundation. We thank David Hurst Thomas, American Museum of Natural History, for his support of zooarchaeology on St. Catherines Island, the opportunity to study the St. Catherines Island animal remains, and for facilitating the publication of this issue of the American Museum of Natural History Anthropological Papers. Funding was provided in part by NSF Award No. BCS-1026167. Over 100 Augusta State University undergraduate students have helped with the St. Catherines Island sampling. We are grateful to them all even if we cannot list them by name. We are also grateful to the diverse group of archaeologists who provided the opportunities to study the vertebrate collections listed in table 3.1, particularly to Carol Colaninno-Meeks and Sarah Bergh for permission to use unpublished dissertation data. An earlier version of this paper was presented at the 75th annual meeting of the Society for American Archaeology, St. Louis.

[15] Isotopic analysis of modern, Cannon’s Point, West, and McQueen otoliths is funded by the National Science Foundation Doctoral Dissertation Improvement Grant BCS-0912176. Isotopic analysis for the St. Catherines Shell Ring is funded by the American Museum of Natural History and Edward J. Noble Foundation. I would like to thank all those who have helped me with this research: David Hurst Thomas, Matthew C. Sanger, Ginessa Mahar, and the crew at the American Museum of Natural History for allowing me to work with the St. Catherines Island collections, Rochelle Marrinan for allowing me to work with the St. Simons material, Bruce Saul, Charles Lambert, and their students at Augusta State University for collecting fishes, Irvy Quitmyer for helping me collect fishes and aiding me at the Florida Museum of Natural History, Fred Andrus for allowing me to work at the University of Alabama, Joe Lambert for processing my isotopic samples, John A. Turck for the map, Julia K. Orr for processing the modern fishes, and Betsy Reitz for the insightful comments. This research could not have taken place without your support, so thank you. The author is responsible for all contents, including the errors and any misinterpretation of the data herein.

[16] I gratefully acknowledge the funding of archaeological research on St. Catherines Island by the Edward John Noble Foundation and the St. Catherines Island Foundation. I also want to acknowledge Dr. Elizabeth J. Reitz, Dr. David Hurst Thomas, and Irvy R. Quitmyer for their support in this research, Carol Colaninno-Meeks and Siavash Samei for their help in the lab, Maran Little for her enormous help sectioning clams, and Lori Pendleton Thomas, Elliot Blair, Anna Semon, and the rest of the 2008 St. Catherines Island archaeology staff and crew for excavating and sorting these materials.