MARINE MAMMAL COMMISSION — Annual Report for 1991 



will undertake recapture efforts, as soon as weath- 

 er and sea conditions permit, and return the 

 captured otters either to the mainland sea otter 

 range or to the translocation zone; 



• the Fish and Wildlife Service, in cooperation with 

 the California Department of Fish and Game, will 

 evaluate the safety, effectiveness, and cost of 

 possible alternative techniques for limiting popula- 

 tion growth, including but not limited to reduction 

 of fecundity and, as part of a long-term manage- 

 ment plan, the appropriateness of selective culling, 

 recognizing that evaluations involving the lethal 

 take of California sea otters could not be permit- 

 ted; 



• the California Department of Fish and Game will 

 be responsible for designing and carrying out a 

 research program, using funds provided by the 

 Fish and Wildlife Service, to evaluate the feasibili- 

 ty of humane, non-lethal methods to experimental- 

 ly maintain the southern boundary of the mainland 

 sea otter range in an area between Point Arguello 

 and Point Conception; and 



• the California Department of Fish and Game will 

 initiate and/or support State legislation to imple- 

 ment appropriate restrictions on the use of gill and 

 trammel nets in the translocation zone. 



Translocation Efforts — Capture of sea otters for 

 translocation to San Nicolas Island began on 24 

 August 1987. As of June 1991, 252 sea otters had 

 been caught along the central California coast for 

 possible translocation to San Nicolas Island. Of these, 

 101 were released at the capture site, or were released 

 before being translocated to San Nicolas Island, 8 died 

 during the translocation process, and 139 were trans- 

 ported to and released at San Nicolas Island. 



Since the translocation was initiated in August 

 1987, 13 pups are known to have been bom at the 

 island; 4 of these are known to have survived to 

 weaning. As of June 1991, 14 of the 139 otters 

 translocated to San Nicolas Island remained at the 

 island; 10 were known to have died; 3 had been 

 recaptured in the Management Zone; and 31 had been 

 resighted back in the mainland range. The fate of the 

 remaining 81 animals is unknown. 



Containment — From September 1987 through 

 June 1991, there were 103 reports and 67 verified 

 sightings of sea otters within the designated Manage- 

 ment Zone. Some of the reports were of seals and sea 

 lions, rather than sea otters, while others were dupli- 

 cate sightings of the same animals. 



In previous years, sea otters sighted in the Man- 

 agement Zone appeared not to stay in one place for 

 very long. In 1991, however, there were indications 

 of animals taking up residence in the nearshore waters 

 of San Miguel Island. A single sea otter was reported 

 by a fisherman at the western end of the island on 30 

 March 1991. A dead sea otter was found on the 

 island on 1 May. This otter was a male that had been 

 translocated to San Nicolas Island on 4 October 1988 

 and sighted near Point Buchon on the mainland on 17 

 October 1989. During an aerial survey on 13 May, 

 nine adults and one pup were sighted in waters around 

 San Miguel Island. The Fish and Wildlife Service has 

 attempted to capture and remove the animals, but to 

 date has been able to capture only two. 



There also are indications that the distribution of 

 sea otters along the mainland California coast is 

 moving south towards Point Conception. On 

 2 January 1991, three independent sea otters and a 

 dependent pup were sighted near Purisima Point, 

 about 12 miles north of Point Conception. During a 

 shore-based count on 4 June 1991, eight independent 

 sea otters and two pups were seen in this area. 

 Although none of the animals had a complete set of 

 flipper tags, the tags present suggested that 3 of the 

 animals likely were animals that had been translocated 

 to San Nicolas Island. 



Inddental Take in Fisheries — When the Califor- 

 nia sea otter population was listed as threatened in 

 January 1977, it was assumed that population size and 

 range were increasing and would continue to increase 

 at about five percent per year until all of the available 

 habitat was reoccupied. As noted in previous Annual 

 Reports, however, subsequent studies indicated that 

 substantial numbers of sea otters were being caught 

 and killed in coastal gill net fisheries and that the 

 incidental take had stopped, and possibly reversed, the 

 population increase. In addition to sea otters and 

 other marine mammals, thousands of seabirds and 



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