Shellfish, Seasonality, and Stable Isotope Sampling: δ 18 O Analysis of Mussel Shells From an 8,800-Year-Old Shell Midden on California's Channel Islands

• Published in: Journal of island and coastal archaeology 2013-05, Vol.8 (2), p.170-189
• Main Authors: Jew, Nicholas P., Erlandson, Jon M., Watts, Jack, White, Frances J.
• Format: Article
• Language: English
• ISSN: 1556-4894; 1556-1828
• DOI: 10.1080/15564894.2012.736917

Analyzing stable isotopes in mollusk shells allows archaeologists to address issues ranging from seasonality of harvest, to settlement and subsistence strategies, sea surface temperatures, and nearshore paleoecology. Studying California mussel shells from an ∼8,800-year-old shell midden on San Miguel Island, we investigate how mollusk growth rates influence sampling strategies for determining seasonality. Using a fully profiled shell as a standard to interpret more limited measurements (terminal growth band plus one) on 39 additional shells, we identified what appeared to be a multi-seasonal occupation. Sampling 20 of the 39 shells more intensively, however, changed our conclusions about season of harvest for 35 percent of the analyzed shells, producing data more consistent with other evidence for a short-term occupation of CA-SMI-693. Sampling strategies for determining seasonality from marine mollusks should carefully consider the ecology of individual species, particularly for fast-growing shellfish such as California mussels. (Author abstract)