To gain insight into pre-contact Coast Salish fishing practices, we used new palaeogenetic analytical techniques to assign sex identifications to salmonid bones from four archaeological sites in ...Burrard Inlet (Tsleil-Waut), British Columbia, Canada, dating between about 2300-1000 BP (ca. 400 BCE-CE 1200). Our results indicate that male chum salmon (Oncorhynchus keta) were preferentially targeted at two of the four sampled archaeological sites. Because a single male salmon can mate with several females, selectively harvesting male salmon can increase a fishery's maximum sustainable harvest. We suggest such selective harvesting of visually distinctive male spawning chum salmon was a common practice, most effectively undertaken at wooden weirs spanning small salmon rivers and streams. We argue that this selective harvesting of males is indicative of an ancient and probably geographically widespread practice for ensuring sustainable salmon populations. The archaeological data presented here confirms earlier ethnographic accounts describing the selective harvest of male salmon.
Pacific salmonid (Oncorhynchus spp.) remains are routinely recovered from archaeological sites in northwestern North America but typically lack sexually dimorphic features, precluding the sex ...identification of these remains through morphological approaches. Consequently, little is known about the deep history of the sex-selective salmonid fishing strategies practiced by some of the region's Indigenous peoples. Here, we present a DNA-based method for the sex identification of archaeological Pacific salmonid remains that integrates two PCR assays that each co-amplify fragments of the sexually dimorphic on the Y chromosome (sdY) gene and an internal positive control (Clock1a or D-loop). The first assay co-amplifies a 95 bp fragment of sdY and a 108 bp fragment of the autosomal Clock1a gene, whereas the second assay co-amplifies the same sdY fragment and a 249 bp fragment of the mitochondrial D-loop region. This method's reliability, sensitivity, and efficiency, were evaluated by applying it to 72 modern Pacific salmonids from five species and 75 archaeological remains from six Pacific salmonids. The sex identities assigned to each of the modern samples were concordant with their known phenotypic sex, highlighting the method's reliability. Applications of the method to dilutions of modern DNA samples indicate it can correctly identify the sex of samples with as little as ~39 pg of total genomic DNA. The successful sex identification of 70 of the 75 (93%) archaeological samples further demonstrates the method's sensitivity. The method's reliance on two co-amplifications that preferentially amplify sdY helps validate the sex identities assigned to samples and reduce erroneous identifications caused by allelic dropout and contamination. Furthermore, by sequencing the D-loop fragment used as a positive control, species-level and sex identifications can be simultaneously assigned to samples. Overall, our results indicate the DNA-based method reported in this study is a sensitive and reliable sex identification method for ancient salmonid remains.
High-resolution stable oxygen isotope analysis of the bivalve Saxidomus gigantea from shell midden sites was applied to identify seasonal patterns of resource procurement on the central coast of ...British Columbia, Canada. A total of 90 archaeological shells were examined from eight distinct sites spanning a 4500-year period. Combining micro-growth pattern analysis with high-resolution stable oxygen isotope sampling allows for a precise season of collection to be determined in estuarine bivalves recovered from archaeological sites. The results of the stable oxygen isotope analysis provide insights into seasonally structured harvest of S. gigantea (butter clam), which is associated with different types of sites. The results show a variety of patterns, including multi-seasonal collection, intensive seasonal harvesting and casual, supplemental use of butter clams at different locations.
► Season of shellfish harvest on the central coast of British Columbia, Canada. ► Integrates sclerochonology and high-resolution stable oxygen isotope analysis. ► Examines 90 shells spanning 4500 years from eight different sites. ► Variation in patterns of seasonal harvesting is observed between sites.
Ancient DNA identification of salmon remains from the site of Namu on the central coast of British Columbia shows use of a variety of species and an emphasis on pink salmon over the course of the ...past 7,000 years. These results support arguments that Namu was a permanent village settlement dependent on a salmon storage economy throughout this time. This pattern of subsistence and settlement predates by several millennia the first substantial evidence for population expansion or social differentiation in the region. Periodic salmon shortages in the period after 2000 cal B.C., which are associated with local and regional disruptions in settlement and increased reliance on more marginal resources, appear to be the result of failures in the pink salmon fishery.
We use ancient DNA analysis to identify Pacific salmon vertebrae to species in order to provide an important line of evidence that helps to establish the timing of seasonal residence at a Pacific ...Northwest Coast village site. Ancient DNA results from House 2 at Dionisio Point allow a characterization of the salmon fishery. Ten of eleven randomly selected smaller-sized salmon vertebrae were positively identified as sockeye salmon (
Oncorhynchus nerka) while only a single pink salmon (
Oncorhynchus gorbuscha) was identified. Of the 322 whole salmon vertebrae identified from House 2 occupation deposits during zooarchaeological analysis, 58 percent measure less than 8.0 mm and 70 percent are less than 8.5 mm in maximum transverse diameter. Together with documented aspects of the material record from Dionisio Point, most notably the vertebrate fauna from House 2, the indication that sockeye was the primary focus of the Dionisio Point salmon fishery suggests the site was inhabited during the spring and summer. This approach to the identification of season-specific site occupation has the potential for application over much of the Northeast Pacific.
► We assess the season of site use at Dionisio Point using ancient salmon DNA species data. ► Results of House 2 zooarchaeological analysis provide important context. ► Smaller-sized vertebrae reveal a 10:1 ratio of sockeye to pink salmon. ► An early spring to summer village occupation is therefore indicated. ► Seasonality determination should be possible at similar sites containing Pacific salmon remains.
The results of high-resolution stable oxygen isotope (δ18O) sclerochronology of 139 butter clam (Saxidomus gigantea) shells from nine archaeological shell midden sites on the central coast of British ...Columbia, Canada demonstrate clear patterns of multi-season harvest at most sites and specific seasonal harvest at particular site locations. Although the results are based on small numbers of shells relative to an unknown number of seasonal clam harvesting events over the centuries or millennia of site occupation, they can be interpreted with confidence based on regional inter-site consistency, fit with a broader range of ancillary archaeological evidence, and the relative stability of seasonal patterns through iterative increases in sample size. On the basis of these results we outline a pragmatic approach to the selection of shells for seasonality analysis and for the interpretation of seasonal harvest patterns. This approach depends neither on the indeterminate reliability of probabilistic sampling of midden deposits and constituents or the prohibitively costly and still potentially unreliable use of large shell samples drawn from deposits distributed across sites.
Biogeochemical and growth increment analyses show contrasting seasonal patterns of butter clam collection and rates of harvest intensity between archaeological shell midden sites from the Dundas ...Islands archipelago and the mainland coast in Prince Rupert Harbour, northern British Columbia. Growth increment analysis shows more intensive clam harvest in the Dundas Islands in comparison to the residential sites in Prince Rupert Harbour. Stable oxygen isotope analysis shows multi-seasonal collection of clams in the Dundas Islands and a more seasonally specific emphasis in Prince Rupert Harbour. Comparison of these results to those of similar studies in the Namu region on the central coast of British Columbia provides a basis for broader regional understanding of variation in shellfish harvesting intensity and seasonality on the Pacific Northwest Coast.
Examination of growth-stage profiles of shells from nine Northwest Coast shell midden sites shows a majority of senile-stage shells at longer-term residential sites and a majority of mature-stage ...shells at shorter-term encampments. This pattern indicates less intensive harvest in the vicinity of residential sites, which is consistent with management and conservation of resources for anticipated future needs. Consideration of environmental and taphonomic factors does not account for the observed inter-site variability. Shellfish conservation in the vicinity of residential sites is evident for the period of the past 7000 years.
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