Pinniped assessment in Point Reyes, California, 1983 to 1984

Allen, Sarah; Huber, Harriet

Final report prepared for the Point Reyes/ Farallon Islands National Marine Sanctuary of the Sanctuary Programs Office, NOAA. Extensive report summarizing the results of a survey of harbor seals, California Sea lions and northern sea lions along the coast of Point Reyes. Looked at the numbers of each species present at different times of the year (different times in the breeding cycle), and compared the results with findings from 1984 to the findings from 1983. Includes tables of data and both tables and graphs which break down the population by sex and age.... We surveyed three species of pinnipeds (harbor seals, California sea lions, and northern sea lions) for a second year in Point Reyes, California, from March 1983 through February 1984. Information gathered for both years (1982—83, 1983—84) are compared. Harbor seals, though present year round, were most abundant during the breeding season; the maximum count for the season was 2449 including 527 pups. The majority of breeding seals migrated to coastal locations rather than estuarine ones. At Double Point the breeding population has expanded three—fold since 1976; the annual rate of growth, though, has not been linear. During the non—breeding season, population numbers have remained stable. Sea lions also were seasonally abundant in Point Reyes. Northern sea lion numbers peaked during the breeding season; California sea lion numbers peaked during the southern spring migration and the northern fall migration when traveling to and from breeding grounds, and peaked again in December during the herring run in Tomales Bay. A significantly larger number of California sea lions, composed of mostly immatures, was present in 1983—84 than in 1982—83. The opuimun time to census sea lions in Point Reyes was between 1100 and 1600 hr when low tides occurred mid day.