Chapter II — Species of Special Concern 



Sea Otter 



{Enhydra lutris) 



The sea otter is the only member of the genus 

 Enhydra and, after the marine otter (Lutra felina) in 

 South America, is the smallest marine mammal in the 

 world. Three subspecies are recognized: E. lutris 

 lutris, E. lutris nereis, and E. lutris kenyoni. 



Historically, sea otters occupied nearshore waters 

 of the North Pacific Ocean from Hokkaido in north- 

 ernmost Japan through the Kuril Islands, Kamchatka 

 Peninsula, the Commander Islands, the Aleutians, 

 peninsular and south coastal Alaska, and southward 

 down the west coast of North America to Baja Cali- 

 fornia. The species' worldwide population before 

 exploitation is estimated to have been 150,000 to 

 300,000 animals. 



Commercial hunting of sea otters began in 1741 

 with the Russian discovery of Alaska and continued 

 on an intense scale and without regulation for more 

 than 150 years. By the early 1900s the total sea otter 

 population had been reduced to as few as 1,000 to 

 2,000 animals existing in 13 small and widely scat- 

 tered remnant groups. 



The first protective measures were taken in 1911 

 when the United States, Russia, Great Britain, and 

 Japan signed the North Pacific Fur Seal Convention. 

 In addition to banning the pelagic take of northern fur 

 seals, the convention provided much-needed protection 

 for sea otters by bringing an end to commercial sea 

 otter hunts. Since that time, sea otters have recolo- 

 nized or have been reintroduced into a substantial part 

 of their historic range in Russia, the Aleutian Islands, 

 south coastal Alaska, British Columbia, Washington, 

 and California. In the past 20 years, however, new 

 threats have developed. They include possible oil 

 spills from tanker accidents and well blowouts, 

 entanglement in fishing gear, chemical pollution, toxic 

 algal blooms, and possible new and rare diseases. 



Efforts by the Marine Mammal Commission and 

 others to ensure the continued protection of sea otters 

 and their habitat have been discussed in previous 

 annual reports. A summary of these actions and a 

 description of efforts undertaken in 1998 follows. 



The Central California Population 



As elsewhere in the species' range, the sea otter 

 population in California was nearly eradicated by 

 commercial hunting in the eighteenth and nineteenth 

 centuries. By the time protection was afforded in 

 1911, the total population in California may have 

 numbered fewer than 50 animals within a few miles of 

 nearshore habitat along the rocky Point Sur coast. 

 Under the Fur Seal Convention and additional pro- 

 tective measures later implemented by the State of 

 California, the population increased slowly. 



In the early 1970s the California population of sea 

 otters was limited to less than 200 miles of coastal 

 waters and contained only about 1,000 individuals. 

 Because of its small size and limited distribution, and 

 the growing risk of oil spills as a result of increasing 

 tanker traffic in the area, the population was designat- 

 ed as threatened under the Endangered Species Act in 

 January 1977. 



At that time, it was believed that the best way to 

 minimize the threat from oil spills would be to en- 

 courage expansion of the population's range. Such 

 range expansion, however, could impact commercial 

 and recreational abalone and other shellfish fisheries 

 that had developed in the absence of sea otters. In 

 light of this possibility, the Marine Mammal Commis- 

 sion recommended in December 1980 that the Fish 

 and Wildlife Service implement a zonal management 

 strategy by which one or more sea otter colonies 

 would be established outside the existing California 

 sea otter range and, at the same time, sea otters would 

 be prevented from recolonizing areas where substan- 

 tial shellfish fisheries existed. 



The zonal management concept was incorporated 

 by the Fish and Wildlife Service into the southern sea 

 otter recovery plan adopted in February 1982. At the 

 time, the Marine Mammal Protection Act contained 

 no provisions for authorizing the take of depleted 

 species of marine mammals for purposes other than 

 scientific research. In 1986 Congress enacted Public 

 Law 99-625 authorizing the development and imple- 

 mentation of a program to establish at least one sea 

 otter colony outside the then-existing sea otter range 

 in California. The law specified establishment of a 

 translocation zone that would meet the habitat needs 



85 



