Stable isotope reconstructions of shellfish harvesting seasonality in an estuarine environment: implications for Late Holocene San Francisco Bay settlement patterns

► Oxygen isotopes faithfully record season of harvest, even in estuarine systems. ► Salinity changes, not temperature, drive annual variation in δ18O in estuaries. ► We suggest a fission-fusion settlement pattern in Late Holocene San Francisco Bay. ► Results highlight the value of small and ephemeral shell middens.