ABSTRACT
MORPHOLOGY OF THE PACIFIC HARBOR SEAL (PHOCA VITULINA RICHARDSI) USING ELKHORN SLOUGH, CALIFORNIA, AND THEIR MOVEMENTS AND DIVING BEHAVIOR IN THE MONTEREY BAY AREA
Harbor seals (n = 169) were captured in Elkhorn Slough, California between September 1991 and November 1996. An exponential relationship was found between mass and standard length. The average growth rate for the 12 recaptured seals with positive growth was 15.4 kg/yr (SE = 2.1). Radio transmitters and time-depth recorders were placed on 38 harbor seals between July 1994 and November 1996. Harbor seals foraged in Monterey Bay over the oceanic shelf, along the shelf break of the Monterey Submarine Canyon, and the mouth of Soquel Submarine Canyon. Depth of dives were less during summer than winter, probably corresponding to the increased productivity over the oceanic shelf caused by upwelling. Positive linear relationships were found between the average depth and duration of dives and mass of harbor seals. A positive non-linear relationship was found between the maximum depth of dives and the average rate of descent.
Tomoharu Eguchi
May 1998
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