CLAM, MUSSEL, AND OYSTER HARVEST AT CA-SFR-114: ESTIMATING SEASONALITY OF SHELLFISH HARVEST USING OXYGEN ISOTOPES.

Seasonality estimates of shellfish harvest at the Middle/MLT Period Yerba Buena site (CA-SFR-114) were determined using oxygen isotope values from three shellfish species: Macoma nasuta (bent-nose clam), Mytilus trossulus (bay mussel), and Ostrea lurida (Pacific oyster). While clam and mussel seasonality estimates are prevalent in archaeological isotopic studies, we also examined oyster seasonality for the first time in California. Overall, harvest was most intensive in summer and fall/early winter, although timing varied by species and temporal component. Bay mussel and Pacific oyster specimens were harvested primarily in the summer months in the Upper Midden area dated to the Middle-Late Transition and Late 1 Period, and the fall months in the Lower Midden area dated to the Middle 3 and Middle 4 periods. Unlike bay mussel and bent-nosed clam, harvest of Pacific oyster specimens was particularly prevalent in the fall months in the Upper Midden area. [ABSTRACT FROM AUTHOR]