The National Marine Mammal Laboratories' California Current Ecosystem Program (AFSC/NOAA) initiated and maintains census programs for California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) at San Miguel and San Nicolas Islands, California. The program documents annual pup births, pup mortality, and temporal patterns in adult and juvenile presence at San Miguel Island. For both species, the database contains field data on the annual number of live pups and dead pups by location. At San Miguel Island, daily counts of adults, pups, and juveniles in a sample area are also available. The data are used to describe population trends and changes in land resource use among the species.

This dataset contains data from the capture and recapture of over 1500 male California sea lions (Zalophus californianus) from Washington between 1989-2006. The data fields include capture data such as time, location, weight, length, and girth for each animal captured. The dataset also includes records of resights of each animal from records collected from observers from California to Vancouver Island, British Columbia, Canada. The dataset also contains information from opportunistic captures of Steller sea lions (Eumetopias jubatus) in the same region.

California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions at San Clemente Island (a small rookery) and San Nicolas Island (a large rookery). Information on the diet of sea lions is obtained from analyzing scats (i.e., fecal samples) and spewings (i.e., vomitus) collected at those two rookeries in January (winter), April (spring), July (summer), and October (autumn). Otoliths (a crystalline structure within the ear organ) from fish and beaks (mandibles composed of chitin) from cephalopods are recovered from the samples by washing each sample through sieves of varying mesh size. Otoliths and beaks, which are shaped and sized differently for each species of fish and cephalopod, respectively, are used to identify and enumerate fish, and cephalopods consumed by sea lions. Also, otoliths and beaks are measured for estimating size of prey being consumed by sea lions.