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Natural Factors AfTecting the Decline of Snake River Salmon: 



"Since most salmon spend the longest portion of their life in the ocean, and most of their 

 growth is derived from marine food sources, oceanic factors must be considered fully as 

 possible in developing a salmon management and restoration program. Oceanic conditions 

 may often override freshwater factors in determining trends and status of salmon populations. " 



□ The dominance of oceanic factors in determining salmon abundance is suggested by the 

 parallel trends in abundance in recent years for salmon stocks from many different 

 freshwater environments along the Pacific Coast Richards and Olsen (1993) demonstrated 

 that Snake River spring chinook runs shared similar periods and trends of decline (from 

 1977-1991) with chinook salmon runs from the Lower Columbia River system, the Rogue 

 River, several Washington coastal streams, and California's Klamath River. Recent 

 comparisons of West Coast steelhead production showed similar downward production 

 trends for hatchery and wild steelhead runs from Oregon, Washington, Idaho, and British 

 Columbia. 



"Marine mammal populations, especially harbor seals and California sea lions, are increasing 

 on the West Coast.. Marine mammal effects on salmon are potentially significant and represent 

 an important factor in recovery. " 



□ In 1990, an increase in marine mammal damage on spring/summer chinook, from a few 

 percent per year to an average of 19.2%, was noted at Lower Granite Dam on the Snake 

 River This damage was thought to be attributable to harbor seals. This information has 

 led some researchers to speculate that losses of Snake River salmon through marine 

 mammal predation may be equal to the combined sport and commercial harvest 



CRA Position - The CRA believes that better information on ocean mortality is needed 

 and this is a major cause of salmon decline. Marine mammal population control must 

 be more aggressive. 



Recovery Plan Cost and Cost-EfTectivencss: 



Note: The Bevan plan does not estimate the cost of the plan or the relative cost- 

 effectiveness of its elements. 



CRA Position - The next step for NMFS and the other federal agencies is to estimate the 

 cost of the individual elements and to determine the cost-effectiveness. This information 

 will provide decision makers a priority listing of elements. The ability of our region to 

 continue to pay for salmon enhancement is a concern. With 1994 costs of $350 million, 

 our expectation is that this plan could replace ongoing efforts and reduce or minimize 

 future costs. 



CRA. June 14, 1994 



