of Fish and Game 1976). If expansion and popu- 

 lation growth are allowed to continue at current 

 rates, doubling of population size could be 

 expected every 15 years. 



Resident sea otters are relatively sedentary; 

 the average linear dimension of the home range is 

 about 2.5 km (Loughlin 1977). Females have 

 larger home ranges (averaging 80 ha) than males 

 (38.5 ha) (Loughlin 1977); however, recent tag- 

 ging studies indicate that some otters, particularly 

 males, use large segments of coastline up to 160 

 km (R. J. Jameson Unpubl.). These individuals 

 spend the winter with large rafts of males near the 

 ends of the range, returning to the central part 

 during the peak breeding season (summer). They 

 have few natural enemies. White sharks appar- 

 ently prey on sea otters (Morejohn et al. 1975). 

 Most mortality seems to occur in young of the 

 year and older individuals (Kenyon 1969, More- 

 John et al. 1975). Sea otters have moderate to 

 heavy loads of internal parasites (Morejohn et al. 

 1975), and these may cause higher mortality 

 during times of stress. Due to the high daily 

 caloric requirement, severe winter storms pre- 

 venting feeding may be responsible for additional 

 mortality (Wild and Ames 1974), 



REPRODUCTION 



Some female sea otters begin reproductive 

 activity at 3 years of age, and all over 6 years are 

 reproducing. Males do not mature until 5 or 6 

 years of age (Schneider 1978). Breeding season 

 peaks from July to September (R.J.Jameson Un- 

 publ.), and pupping is most frequent from Novem- 

 ber through March (Vandevere 1970). Implanta- 

 tion is delayed 4 to 4'/2 months, and development 

 then proceeds for 4 to 4V2 months, making the 

 gestation period 8 to 9 months overall (Sinha et 

 al. 1966, Schneider 1978). Twinning is rare 

 among sea otters, and it is unlikely that a female 

 could support two pups. Two years has been ac- 

 cepted as the interval between births (Kenyon 

 1969), but recent studies in Alaska and California 

 indicate that some females pup in consecutive 

 years. 



MANAGEMENT AND CONSERVATION 



The California sea otter population currently 

 represents a slowly recovering population of ma- 

 rine mammals occupying only part of its original 



range. With few natural enemies, continued growth 

 in numbers and range may be expected. Because 

 of its relatively low reproductive potential, con- 

 tinued protection from human predation and 

 habitat degradation will be necessary if this 

 recovery is to continue. The most recent sea-otter 

 survey, conducted by the California Department 

 of Fish and Game in 1979 resulted in an estimate 

 of less than 1,500, a decrease of about 300 from 

 the 1976 census. Since the weather conditions 

 during the 1979 survey were unfavorable, it is 

 considered quite low. 



Kelp forests growing along rocky coasts ap- 

 pear to constitute optimum otter habitat in Cali- 

 fornia. Estes and Palmisano (1974) indicated that 

 sea otter predation on herbivores may be impor- 

 tant in the maintenance of large stands of kelp. If 

 increased growth of macrophytes is correlated 

 with this predation by sea otters, their presence in 

 an area may increase primary productivity. The 

 trophic consequences of the reestablishment of 

 the sea otter population remain to be seen. Mean- 

 while, protecting the kelp bed habitat from physi- 

 cal and chemical degradation will continue to be 

 important for the entire littoral ecosystem. 



The southern sea otter now occupies only a 

 small fraction of its original range. The continuity 

 of the sea otters' current territory makes the 

 species quite vulnerable to catastrophic events 

 and augments the importance of establishing 

 satellite populations in other parts of its former 

 range to insure its survival. Previous translocation 

 programs have demonstrated the feasibility of es- 

 tablishing new populations of the sea otter (Ken- 

 yon 1969, Jameson et al. 1978). Estabhshment 

 of satellite populations will greatly decrease the 

 probability of the entire population's being des- 

 troyed by an epizootic or an oil spill. 



In the past 10 years, questions have arisen 

 concerning the compatabiHty of the sea otter 

 with sport and commercial shellfishing interests. 

 The abundance of large abalones, sea urchins, and 

 Pismo clams diminishes following reoccupancy of 

 an area by sea otters (Miller 1974, Woodhouse et 

 al. 1977). However, other studies indicated that 

 after the initial period of reinvasion, the diet of 

 the sea otter becomes more diverse, and the com- 

 munity food web may enjoy a broader base 

 resulting from reduction of the numbers of large 

 herbivores (Palmisano and Estes 1977, Rosenthal 

 and Barilotti 1973), and a consequent increase of 



