Investigation of Seasonal Settlement and Clam Harvest Pressure in the Sechelt Inlet System, British Columbia, Canada, Through Sclerochronology and Stable Oxygen Isotope Analyses

The Sechelt inlet system (SIS), situated on the inner Sunshine Coast of British Columbia, lies within the territory of the shíshálh Nation. This study focuses on ∼1000 years of shíshálh shellfish harvesting from 930-0 cal. BP. Specifically, we investigated the seasonal timing of shellfish collection, relative shellfish harvesting pressure and paleo-temperature reconstruction at four archaeological sites. Thirty archaeological butter clam shells (Saxidomus gigantea) from the SIS underwent high-resolution shell oxygen isotope (δ18O) analysis and 662 individual archaeological shell fragments were analysed for growth stage determination. The δ18O results showed a pattern of year-round collection with an emphasis on spring collection at village sites. Results from shell growth stage analysis suggest an intensive pattern of shellfish harvesting in the region, regardless of the site type. Archaeological shells show a larger δ18Oshell range, possibly reflecting a greater sea surface temperature amplitude than modern shells (i.e. a difference of ∼6.5°C; modern range: ∼3.7–20.4°C; archaeological range: ∼ −0.8–22.4°C). We contextualise our results with previous studies of seasonal timing and intensity of shellfish harvesting from the Pacific Northwest Coast, while interpreting these new data in the context of shíshálh occupation and landscape use.