MONITORING ENDANGERED BLACK ABALONE ON VANDENBERG AND SAN CLEMENTE ISLAND

Karah N Ammann; karah.ammann@ucsc.edu; Christy Bell, Pete Raimondi, Melissa Miner, Nate Fletcher

Since the mid 1980s, black abalone (Haliotis cracherodii) have experienced mass mortalities due to "withering syndrome" and are currently protected under the Endangered Species Act. Multi-Agency Rocky Intertidal Network (MARINe) has monitored abalone populations on the California coast for over 20 years and have documented their decline. Monitoring data show that once a population crashes, community structure changes, possibly contributing to recruitment failure. We have assessed abalone populations and habitat quality on two military lands: Vandenberg Air Force Base (US Air Force) and San Clemente Island (US Navy). Abalone populations on Vandenberg were some of the earliest on the mainland to experience decline. We have monitored sites since 1992 on Vandenberg and monitoring here was crucial to documenting the northward spread of the disease. In 2011-12 we conducted abalone population and habitat surveys on San Clemente Island. These surveys found only a remnant population of black abalone and suggested that the lack of adults may reduce suitable recruitment habitat. We initiated a habitat restoration trial in which cracks were cleared of fouling organisms to conditions consistent with the presence of adults. We are continuing this restoration approach by maintaining crack clearings, installing and testing abalone recruitment modules, and monitoring for recruitment and signs of disease.

Ecology and Management of Wildlife on Military Lands