First Reported Occurrence of the Southern Sea Otter Enhydra lutris lutris at California's Santa Barbara Island Since 1940

Abstract

Sea otters once ranged along the North Pacific rim from the northern Japanese islands to mid-Baja California, Mexico. There are three recognized subspecies of sea otters: the Russian or Asian sea otter (Enhydra lutris lutris); the Alaskan or northern sea otter (E. 1. kenyoni); and the California or southern sea otter (E. 1. nereis) (Wilson et al. 1991). The southern sea otter occupies the most southerly range, with populations in only two areas of California: the mainland coastline from San Mateo County to Santa Barbara County and San Nicolas Island, Ventura County.1 Historically, 16,000-20,000 sea otters are believed to have resided in the area that is now California.2 The southern sea otter was afforded protection in California by the California Department of Fish and Game in 1913.3 In the 1970s, the California population of sea otters was restricted to the Central California coast.4 Primarily due to concerns about the vulnerability of this population to oil spills, the southern sea otter was listed as threatened by the United States Fish and Wildlife Service (the Service) under the Endangered Species Act in 1977.5 The Service approved the first recovery plan for the southern sea otter in 19826 and released a final environmental impact statement in 1987. This EIS evaluated several options including translocating southern sea otters from California’s central coast in an attempt to form a discrete colony of animals at San Nicolas Island, located 111 km (60 nm) off the Southern California coastline.7,8 Through translocation, the Service hoped to establish a self-sustaining southern sea otter population at a location within their historic range, but well away from the central coast population to lessen the risk to the species should a natural or man-made catastrophe decimate the central coast population. To achieve project goals, the San Nicolas Island colony would