According to a May 16 Columbian guest column authored by Bryan Irwin, Northwest regional executive director of the Coastal Conservation Association, the mark-selective recreational fishery for summer chinook has “clear biological benefits for salmon and is part of the solution to increasing wild fish returns to their native habitats while providing increased fishing opportunity for hatchery salmon.” The truth is somewhat murkier, however.
Summer chinook have a relatively low mark rate. For several years it was figured to be 35 percent-40 percent, meaning fewer than four out of 10 of these fish were adipose fin-clipped hatchery fish. That means that an angler would have been likely to handle at least three unmarked, and therefore presumably wild, summer chinook for every two hatchery fish retained. Washington Department of Fish and Wildlife recently revised the mark rate upwards to around 60 percent, which is still significantly lower than the mark rate for spring chinook.
Irwin’s claim that the mark-selective fishery is beneficial is dependent on the certainty that unmarked fish caught and released survive the experience. There is a slight problem with that assumption: There are no independently verifiable data to back it up. No one has ever conducted a hooking mortality study on the Columbia River.
One of the problematic issues regarding release mortalities in mark-selective fisheries is water temperature. The waters of the Columbia River during summer chinook season tend to be about 65 degrees, which is nearing the point where the temperature alone can cause salmonid mortalities. Add to that the stress of being hooked, played out, handled and released and one can readily see that it is highly possible that a good many of these fish will not, in fact, survive the experience.