Ernest O. Salo

THE ROLE OF PUGET SOUND AND WASHINGTON COASTAL ESTUARIES IN THE LIFE HISTORY OF PACIFIC SALMON: AN UNAPPRECIATED FUNCTION

Washington State has approximately 100 diverse estuaries, ranging from the more classic coastal estuaries to Puget Sound, a continuum of estuaries with transitional habitats. Of the five Pacific salmon species, chum and chinook utilize these estuaries most extensively. Estimated residence times of individual juvenile salmon range from 4 days (chum salmon) to 6 months (chinook) while individual residence times of adults range from 1–6 weeks. Some salmon populations may, however, remain within Puget Sound until maturity. Juveniles of all species utilize neritic habitats, but chum and chinook also use shallow, sublittoral habitats. Abundant, uniquely estuarine prey organisms are eaten by juveniles of all species, although less so by pink, sockeye, and coho, and contribute to high growth rates in estuaries. Significant predation on juveniles in estuaries has yet to be documented. We hypothesize that Pacific salmon use Washingtons estuaries for: 1) productive foraging, 2) physiological transition, and 3) refugia from predators. These functions have probably changed due to salmon culture practices and alterations of estuarine habitat, and it is possible these changes could adversely impact salmon growth and survival. The importance of estuaries to salmon production should be more carefully considered in estuary and salmon management.

Man's Impact on the Columbia River Stocks of Salmon*

ABSTRACT The impact of man on the salmon and steelhead of the Columbia River includes 35 years of effort to prevent declines in the stocks. Between 1866 and 1940, the commercial fishery harvested an annual average of 29 million pounds of salmon and steelhead, but in the next 35 years the annual average harvest dropped to 8 million pounds. During these 35 years the habitat for anadromous fishes dropped from 163,200 to 72,800 square miles. Various approaches to mitigation were tried, but the cumulative effects of the impacts were not compensated for and the runs declined. The productivity in terms of returning adults per spawner has become less than 1 for the upper river stocks. The management flexibility of allowing additional losses at any stage in the life history of these stocks has been lost. Thus, a policy of zero impact for all new developments has been adopted.