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2030 SE Marine Science Dr, Newport, OR 97365

https://hmsc.oregonstate.edu/pastseminars
Free Event

Speaker: Alejandro Acevedo-Gutierrez, Marine Mammal Ecology Lab, Western Washington University

Topic: Foraging ecology of harbor seals in the Salish Sea 

Harbor seals are the most abundant and widely distributed pinniped in the Salish Sea.  Their numbers increased exponentially since 1972 and stabilized for the past 20-25 years.  Simultaneously, numbers of the iconic Chinook salmon have been declining, leading to the hypothesis that harbor seals impede the recovery of salmon and calling for their management.  Prior research has described foraging variability among individual harbor seals and the possibility of some level of individual specialization.  In this talk, I share additional student-led research on the foraging ecology of harbor seals that provides information to help direct management efforts.  1) From scat collected at 13 haul-out sites in the Salish Sea during 2012-2018, the overall sex ratio at haul-out sites had notable spatiotemporal variation and Chinook salmon comprised ca. three times more of the average male harbor seal’s diet than the average female’s diet.  Three haul-out sites where Chinook salmon appear to be under high predation pressure by male harbor seals were identified.  2) From observations of harbor seals at a haul-out site in downtown Bellingham during 2007-2023, there was a decrease in the number of seals hauled-out after the removal of an artificial haul-out site (a proposed non-lethal method aimed at managing seal predation) and an increase in the number of seals foraging at the adjacent river mouth.  Results suggest that initial management strategies focus on specific geographic regions, targeting salmon stocks rather than species, and address the influx of seals from haul-out sites surrounding the management target site.  At a broader level, management will need to incorporate several long-term strategies across the region. 

  • Saeed Ebrahimnezhad Darzi

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