Habitat Assessment: Pacific Herring and Oil
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Pacific Herring (Clupea pallasii) |
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Few species of fish are of greater ecological importance
than the Pacific herring, a species central to the diet of many birds, fish, and
marine mammals in Alaska. The Prince William Sound herring population
collapsed 4 years after the Exxon Valdez Oil Spill, igniting debate
about the cause. Some parties, such as commercial fishermen who once depended
on this stock for income, are convinced that the spill was causal, others are not.
Our researchers organized an interagency group of experts
to reexamine the role of oil in limiting the recovery of herring in Prince
William Sound. There were certainly toxic effects of the spill to herring
embryos and larvae in 1989, but lingering oil today is not suspected of having
a continuing effect. The lack of recovery today cannot be linked directly to
the oil spill, nor can it be eliminated as a root cause. Disease continues to
plague this population, while other populations in the state do not experience
this sort of continuing stress. Predation pressure from marine mammals may now
play a role. Genetic diversity is high and does not appear to play a role in
limiting the population recovery. Continued research of Pacific Herring and
their role in the marine food web is needed so management and conservation of
this species in Alaska is maintained.
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