Population Status and Condition of the Harbor Seal, 'Phoca vitulina richardsi', in the Waters of the State of Washington: 1975-1980

摘要

The study was initiated in 1977 to obtain basic information of the status and condition of harbor seals in Washington waters. Data were obtained by aerial and ground observations, and by examination of collected specimens. A minimum estimate of 9,941 harbor seals in state waters was obtained for the years 1975 to 1980. Best census data were from the primary study areas of Grays Harbor, Willapa Bay and Puget Sound by use of aerial photographic and ground surveys. In addition to the primary study areas, all known haulout areas (216) in state waters were also surveyed for maximum haulout counts. Patterns of seasonal use were identified in the coastal estuaries, related to regional movements and exchange between preferred feeding and pupping areas of the region. Increases in total counts appears to be due to both an increase in seals and to total survey coverage of all known haulout areas. Seventy-seven seals were collected in Grays Harbor for age and sex composition, reproductive condition, health, and food habits, and to secure a reference collection of specimen materials.