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HARBOR SEAL ( PHOCA VITULINA ) PREDATION ON SEINED SALMONIDS IN THE LOWER KLAMATH RIVER, CALIFORNIA
Author(s) -
Stanley William T.,
Shaffer Kevin E.
Publication year - 1995
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/j.1748-7692.1995.tb00292.x
Subject(s) - phoca , harbor seal , predation , fish <actinopterygii> , fishery , piscivore , biology , ecology , predator
A bstract Feeding activity of harbor seals ( Phoca vitulina ) was monitored while the California Department of Fish and Game seined and tagged migrating adult salmonids between 1984 and 1988. The number of predations observed each week of observation was significantly correlated with the number of fish seined during that week. There was a significantly higher number of predations observed on days when seining took place than on days when no seining occurred. Our observations suggest that most, if not all, predations we observed on days when seining occurred involved fish that had been recently seined and released. The estimated percentage of seined fish taken by seals was relatively constant over the five years of the study, ranging from 3.1% to 5.5%. Various strategies for reducing the level of predation on seined salmonids in the lower Klamath River are discussed.