Abundance, movements, dive behavior, food habits, and mother-pup interactions of harbor seals (Phoca vitulina richardsi) near Monterey Bay, California

• Main Author: Stephen John Trumble
• Other Authors: James T. Harvey, Gregor Cailliet, David Grubbs
• Format: Master Thesis
• Language: English
• Published: California State University, Fresno 1995
• Subjects: harbor seal; Phoca vitulina
• Online Access: https://hdl.handle.net/20.500.12680/sb397h213

Data concerning movements of radio-tagged harbor seals (Phoca vitulina richardsi), along with abundance, food habits, and mother-pup suckling behavior were analyzed to better understand the ecology of harbor seals in Monterey Bay, California. Based on a mean index of relative importance (IRI) using 222 fecal samples, Sebastes sp., flatfishes (Pleuronectidae and Bothidae) and Chilara tavlori were the primary fishes consumed. Loligo opalescens and Octopus rubescens were the primary prey species consumed before pupping. Female harbor seals abandoned their pups during mid-lactation, presumably foraging. Diel observations were conducted on harbor seal mother-pup pairs during the 1992pupping season at South Fanshell Beach, Monterey Bay, California. Mean proportion of animals suckling per hour was significantly greater for diurnal periods (X= 0.51 h-1, SE = 0.28-1) compared with nocturnal periods (X= 0.23 h-1, SE = 0.19-1; z = 3.35, p < 0.05). Diurnal suckling was 117% greater than nocturnal, which may prove important in energetic studies.