Early Red Abalone Shell Middens, Human Subsistence, and Environmental Change on California's Northern Channel Islands

Abstract

Red abalone (Haliots rufescens) shell middens, a distinctive site type on the California Coast dating primarily to the Middle Holocene, provide important insight into human-environmental interactions and climatic and environmental change. Despite decades of research and debate about why red abalone middens formed and how they relate to past human behavior and environmental change, significant questions persist about the nature of these sites and how they relate to broader trends in human diet and land use. Here, we present the results of excavation at three red abalone middens on the northern Channel Islands. Two of these middens, CA-SRI-26 on Santa Rosa Island and CA-SMI-692 on San Miguel Island, are among the older reported red abalone middens, at roughly 8000–7300 cal BP, and help fill a significant temporal gap in our understanding of the initial period of intensive red abalone harvest. The third midden, CA-SMI-172, dates to ~6300 cal BP and fills a spatial gap on eastern San Miguel Island. When placed in the context of other Channel Island red abalone middens, our analysis demonstrates that people at some of the earliest red abalone middens harvested more red abalone and larger sized individuals than later in time. These data suggest that people likely placed predation pressure on red abalones across the red abalone midden period (8500–3500 cal BP) and that human activities worked in tandem with other environmental changes to influence the disappearance of the red abalone midden phenomenon ~3500 years ago.