Updated: 27 September 2012
Rockfish not a major part of local seals' diet
A study published last week in the journal Marine Ecology Progress Series indicates that robust local seal populations consume a diverse menu of fishes and invertebrates and that depressed rockfish species are not a major part of their diet.
The Salish Sea has a very robust harbor seal population that has been at or near carrying capacity for nearly two decades. This has made fishers and scientists wonder what impact these top-level predators could be having on the recovery of depressed fish populations.
Approximately 15% of the fish species in the region are listed as threatened, endangered, or are candidates for listing. A multi-year study funded by the SeaDoc Society (a marine science program of the UC Davis School of Veterinary Medicine), the National Science Foundation and the Washington Department of Fish and Wildlife provides insight into this complex question.
According to Monique Lance, a wildlife research biologist at the Washington Department of Fish and Wildlife and the lead author of the study, "harbor seal diet is quite diverse, not only in the species they eat, but also in the variability we see depending on the season, year and location." Harbor seals consumed over 45 species of fishes as well as invertebrate species like squid, octopus and shrimp.
While individual seals likely have different dietary preferences, as a group, seals feed on fish that are seasonally and locally abundant. They eat more salmon in the summer and fall (especially pink salmon when they are running), herring year-round, and sand lance, anchovy and juvenile walleye pollock during the winter and spring.
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