Pismo clam (Tivela stultorum) populations were previously abundant on the California central coast before declining dramatically in the late 1970s and 1980s. However, recently their population has been increasing. The southern sea otter (Enhydra lutris nereis) was hunted to near extinction in the 1800s, leading to a dramatic reduction of their range, including their extirpation from Pismo Beach. Their population has since been recovering, and they are repopulating historic range locations including Pismo Beach in the 1970s, which coincided with the decline in clam populations locally. Since sea otters are an important predator of Pismo clams, we sought to explore the potential impact of sea otter predation on Pismo clam population abundance and recovery by conducting otter foraging surveys on three local beaches. Our preliminary results found that sea otters are commonly seen at the north-most end of Pismo State Beach, and their diet consists of primarily Pismo clams. This data will help illuminate the impact of sea otter predation on Pismo clam populations, and we hope it can help inform management practices to support both species’ recoveries on the Central Coast.

Isa Mattioli is a fourth year Animal Science student at Cal Poly SLO with minors in Biology, Environmental Studies, and Spanish. They have a passion for marine ecology and work in research labs with species such as elephant seals and Pismo clams. They plan on going to graduate school after college with the ultimate goal of becoming a marine biology professor.