Human Impacts on Seals, Sea Lions, and Sea Otters: Integrating Archaeology and Ecology in the Northeast Pacific

6. An Analysis of Seal, Sea Lion, and Sea Otter Consumption Patterns on Sanak Island, Alaska: An 1800-Year Record on Aleut Consumer Behavior

111 6 An Analysis of Seal, Sea Lion, and Sea Otter Consumption Patterns on Sanak Island, Alaska an 1800-year record on aleut consumer behavior Veronica Lech, Matthew W. Betts, and Herbert D. G. Maschner The sanak island biocomplexity project investigates the roles that humans played in North Pacific ecosystems during the Middle-to-Late Holocene. The underlying premise of the project is that prehistoric peoples, with traditional technology, were significant forces in marine ecosystems and, like all taxa, actively engineered environments to both their advantage—and potentially to their detriment (Maschner et al. 2008, n.d.). Excavations of shell middens on Sanak Island have generated a 4500-year time-series of marine mammal remains . An analysis of otariid and sea otter remains (Figure 6.1; Betts et al. this volume) suggests that the frequencies of Steller sea lions, northern fur seals, and sea otters fluctuated over time, likely in response to both natural resource depressions and the adaptation of local populations to human predation (see also Tews 2005). Since body size plays an important role in carcass processing decisions, fluctuations in the abundance of large-bodied marine mammals must have had impacts on the butchery and transport of their carcasses. In general, large animals must be butchered to allow for easier transport, storage, and consumption, while smaller animals are often transported whole for storage and consumption (e.g., Bettinger 1991; Binford 1981; Gifford-Gonzalez 1989; Lyman 1991, 1992a). The prey choice model predicts that as the availability of large-bodied taxa decline, predation on smaller-bodied and lowerranked taxa increases (Stephens and Krebs 1986). This change in foraging efficiency and return rate must have affected decisions regarding Human Impacts on Seals, Sea Lions, and Sea Otters: Integrating Archaeology and Ecology in the Northeast Pacific, edited by Todd J. Braje and Torben C. Rick. Copyright © by The Regents of the University of California. All rights of reproduction in any form reserved. 112 consumption pat t erns on sanak is l and their impact on consumption strategies. Ultimately , our research illustrates the importance of investigating patterns of marine mammal transport and butchery as part of historical ecological analyses. ALEUT PROCUREMENT AND PROCESSING STRATEGIES The Aleut occupation of Sanak, characterized by evidence for the hunting of marine mammals , deep-sea fishing, intensive exploitation of intertidal zones, and semi-sedentary to sedentary villages, exhibits traits consistent with a “developed maritime culture” (Ames and Maschner 1999; Fitzhugh 2003; Price and Brown 1985; Workman and McCartney 1998). Yesner (1980; see also Maschner 1998, 1999) has previously described the propensity for Aleut costal settlements to be optimally located to benefit from multiple resource patches, similar to a “logistical,” or collecting, strategy as de- fined by Binford (1980). On Sanak Island, this logistical site placement strategy appears to have taken three primary resource patches into account: (1) the location of marine mammal rookeries and haul-outs, (2) the location of rich intertidal resources, and (3) the location of groundfish stocks. Unlike the western Alaska Peninsula (e.g., Maschner 1998), salmon streams play a more limited role in determining site processing times of both large- and smallbodied prey. As described by Nagaoka (2006; see also Kopperl 2003; Lyman 1987, 1991; Rapson 1990), a decline in foraging efficiency and a shift toward hunting smaller-bodied prey may be associated with an increase in carcass processing time, as predators attempt to maximize energy returns through intensive processing . When large-bodied prey are abundant, and forging efficiency is high, processing times may be truncated, and the intensity of processing of animal carcasses should be lower (see discussion below). In this chapter, we analyze element and cut mark frequencies to assess the response of Aleut processing and transport strategies to variations in marine mammal abundance. We propose that during times of declining encounter rates for large-bodied marine mammals, the inhabitants of Sanak Island exploited marine mammal carcasses more intensively, an activity that should be detectable in element distributions, cut mark location, and cut mark intensity. Frequencies of marine mammal remains in the last four temporal contexts in the Sanak Island sequence appear to be linked to climatic and population shifts (Betts et al. this volume). For this chapter we have chosen to focus our analyses on the latter half of the postNeoglacial , where we might better speculate on the relationship between climatic changes and 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8...