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What About Salmon?
Our group within NOAA has not studied the effects of the Exxon Valdez spill on salmon stocks (the Alaska Department of Fish and Game is the authority on salmon-related issues in Prince William Sound). The regional economic importance of salmon harvests in Alaska has made any potential effect of the spill on salmon a bitterly controversial issue and one that is difficult to ignore.
By far the most important species of salmon in the Sound is the pink salmon (photo at left). In the first few years following the spill, there was an alarming decline in pink salmon harvests, raising legitimate fears that a long-term and continuing effect of oil was affecting the fish.
However, many factors can affect the size and health of a returning salmon population, including
- the temperature of the ocean waters where the fish spend most of their lives.
- the availability of prey items.
- predation by marine mammals or birds.
- human fishing pressure.
- loss or degradation of spawning habitat.
Obviously, most of these have very little to do with an oil spill. Other salmon populations on the Pacific Coast also are not faring very well, and scientists believe some of the above influences are responsible. It may be that the 1989 oil spill was an additional stress on pink salmon populations in Prince William Sound, but the fact is that it is nearly impossible to know for sure why the salmon did so poorly between 1990 and 1993.
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Prince William Sound pink salmon harvests following the Exxon Valdez oil spill.
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Fortunately, Prince William Sound pink salmon returns in 1994 and 1995 broke the pattern of declining returns since the Exxon Valdez spill. In fact, the 1994 harvest was one of the largest ever. Does this mean that the fears of an oil spill impact were unfounded? Not necessarily: concerns remain about the status of the wild salmon stocks in the Sound (vs. hatchery-reared stocks), and studies conducted under the Exxon Valdez Restoration Program have indicated that pink salmon stocks in oiled areas may have suffered genetic damage--the long-term conseqences of which can only be guessed at the present. As a result, the health of salmon populations in the spill-affected area will likely be watched, studied, and debated for many years to come.
Other Pages in this Series
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