Effects of the 1982–83 El Niño on Several Population Parameters and Diet of California Sea Lions on the California Channel Islands

摘要: Prior to the 1982–83 El Nino, California sea lion (Zalophus californianus) populations in Channel Islands were recovering from low abundance levels that resulted unregulated exploitation and indiscriminate killing which began 1800s continued through late 1930s (Bonnot 1937; Bartholomew 1967; Stewart et al., press). There has been an increasing trend on since 1958 (Bartholomew Odell 1971; Le Boeuf Bonnell 1980; Based upon counts of pups born between 1971 1981, population at San Miguel Island increased about 5% annually (DeMaster al. 1982). The is estimated number 87 000 animals (Boveng 1988).