Paleoclimates of Mi’kma’ki: a sclerochronological analysis of Crassostrea virginica from an archaeological context in Malpeque Bay, Prince Edward Island

Abstract

Pituamkek (CdCw-5), situated on Hog Island, in the province of Prince Edward Island, lies within the territory of the Mi’kmaq Nation. This study focuses on traditional oyster harvesting of the Mi’kmaq from 643-184 cal. BP. Specifically, we investigated the seasonal timing of shellfish collection and paleo-temperature reconstruction at the archaeological site. Ten archaeological eastern oyster shells (Crassostrea virginica) along with with two live collected valves (September 2019) from the surrounding Malpeque Bay underwent high-resolution shell oxygen isotope (δ¹⁸O) analysis and 180 individual archaeological shell fragments were analysed for growth stage determination. The δ¹⁸O results showed a pattern of year-round collection with an emphasis on warm weather collection. Results from shell growth increment analysis suggest the oysters at this region show high levels of stress in response to the conditions of the ambient environment and low sea surface temperatures. Archaeological shells show a larger δ¹⁸Oshell range, possibly reflecting a greater sea surface temperature amplitude than modern shells (i.e. a difference of ~10.9℃; modern range: ~ -1.7℃ to 17.5℃; archaeological range: ∼0℃ to 10.8℃). Results are contextualised with previous studies of paleoenvironmental analysis using oysters from the Eastern Seaboard in the USA, while interpreting these new data in the context of Mi’kmaq occupation and landscape use.