Abstract:
This dissertation is focused on shedding the taphonomic overprint at the Mink Island site (XMK-030) to assess temporal variability of the fish bone assemblage and to establish sample selection criteria for stable isotope (delta15N, delta13C) analysis. These retrospective data may be used to identify the causes and consequences of long-term variability in local fish assemblages when combined with modern fisheries and paleo-oceanographic data. To use these data, it is essential to account for the effects of biostratinomic and diagenic agents. Intertaxa and inter-elemental differences in bone density, shape, size, protein, and lipid content result in differing preservation and contamination potential. Without mitigating for the effects of these biostratinomic and diagenic agents, temporal changes in abundance may be skewed in favor of skeletal elements that best survive destruction. Moreover, stable isotope values may reflect differences in preservation and contamination rather than variability in ecosystem structure and function. The results of several experiments conducted to assess preservation and contamination levels of Mink Island fish bones revealed that: 1) Preservation and contamination potential are linked with completeness percentages and burial duration, but not with bone volume density; 2) Pacific cod dentaries that are intact, unburned, and free of visible contaminants are best suited for stable isotope analysis; 3) The modified Bell pretreatment method is validated for archaeological fish bones; and 4) Because color-affecting contaminants cannot be removed without heat, color-based methods are unsuitable for assessing the cooking/burning stage of archaeological fish bones. Interactions among humans and fishes at Mink Island were assessed using a four-stage resource depression and intensification model. The Mink Island occupants shifted their focus from small flatfishes during Stage I (7500-4500 cal. BP), to Pacific cod and sculpins during Stages II (4500-2800 cal. BP) and III (2800-900 cal. BP), to a mixture of taxa (sculpins, cods, herring, and salmon) during Stage IV (900-400 cal. BP). A decrease in Pacific cod fork lengths indicates that resource depression occurred during Stage II. Taxonomic proportion, evenness, salmon index, and skeletal element representation data demonstrate that salmon intensification did not occur during any stage at Mink Island.
