fornia include the following: abalone [Haliotis 

 sp.), Turban snails {Tegula sp.), sea urchins 

 (Strongylocentrotus sp.), rock crabs {Cancer 

 sp.), kelp crabs {Pugettis. sp.), mussels {Mytilus 

 sp), Pismo clams (Tivela stultorum), and octopus 

 [Octopus sp.). (Hall and Schaller 1964, Ebert 

 1968, Wild and Ames 1974, Miller et al. 1975, 

 Woodhouse et al. 1977). 



In recently reoccupied habitat, the diet may 

 consist almost exclusively of readily available 

 large food items such as abalone, sea urchins, 

 and Pismo clams, but with continued occupancy 

 and consequent depletion of large, easily obtained 

 food items, the otters' diets become more diverse 

 (WUd and Ames 1974). 



SHELTER REQUIREMENTS: 



Sea otters in California do not 'haul out' as 

 frequently as they do in Alaska; however, in re- 

 cent years several regular hauling areas have been 

 discovered. These areas are used primarily during 

 the winter and spring months when kelp beds are 

 reduced in size, and air and water temperatures 

 are lower (R. J. Jameson, unpubl.). Most of the 

 year, otters seek shelter in the extensive beds of 

 g\3int kelp that occur throughout most of the 

 present range. 



area for extended periods (Loughlin 1977). Dur- 

 ing the breeding season, a male-female pair may 

 remain together for only one copulation, or may 

 form a bond that can last several days (Kenyon 

 1969, Vandevere 1970). It is not known if a spe- 

 cial set of habitat characteristics are required for 

 courtship and breeding, but available information 

 suggests there are none. 



OTHER ENVIRONMENTAL REQUIREMENTS 



Lacking a layer of blubber, sea otters depend 

 on air trapped in their dense fur for insulation 

 against heat loss to their environment (Kenyon 

 1969). With captives, Kenyon discovered that 

 soiled fur rapidly loses its insulating ability, ren- 

 dering the animal a sure victim to hypothermia. 

 Recent experiments in Alaska have shown that 

 sea otters exposed to crude oil floating on the 

 water can die (Siniff et al. 1977). This finding is 

 of critical importance, since it relates to the po- 

 tential damage to otters from offshore oil pollu- 

 tion. Although no wild sea otter deaths have yet 

 been reported from oil pollution in California, 

 a major spill could be very damaging (California 

 Department of Fish and Game 1976). 



NESTING OR BEDDING: 



Sea otters may roll themselves in kelp fronds 

 while resting or sleeping, presumably to avoid 

 transport by wind and currents. Mothers wdll 

 similarly leave pups in kelp while diving for food 

 (Fisher 1939). Typical haul-out areas are rela- 

 tively low-lying intertidal rocks covered with a 

 lush growth of a variety of marine algae. 



RITUAL REQUIREMENTS: 



Sea otters are most frequently members of 

 aggregations known as 'rafts' (LoughUn 1977, 

 Schneider 1978). Territoriality may be expressed 

 by some males who defend areas near female 

 rafts, but the evidence for territoriality is circum- 

 stantial and needs to be better documented. 

 Otters are known to remain in the same limited 



POPULATION NUMBERS AND TRENDS 



The rate of increase of the California sea otter 

 population has been 5.4% per year since 1940 

 (Woodhouse et al. 1977). The present population 

 is far below the 16,000 estimated as the potential 

 for California waters (California Department of 

 Fish and Game 1976), or the estimate of 47,800 

 given by Miller (1974) for all waters from the 

 Oregon-California border to Morro Hermoso, Baja 

 California. While the currently occupied range 

 may be nearing carrying capacity, population 

 growth has occurred in recent years by expansion 

 of the range both up and down the coast (Wild 

 and Ames 1974). Observations indicate that high 

 densities of otters occur at the limits of the range. 

 These groups, consisting primarily of males, move 

 into unoccupied territory as the food supply 

 behind them is depleted (California Department 



