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Chinook salmon populations from the Eogu« River in southern 

 or«gon ar« depr«ssed, while populations north of the Rogu« River, 

 except for the Snake Riv«r «nd possibly the mid-Colunbia euBireer 

 (fall type) Chinook run, are satisfactory and in fact are 

 •xploitable. Population status (except Coluabia-SnaJce 

 populations) corresponds primarily to aigration behavior aund 

 ocean conditions. California and Oregon coastal echo and 

 southern Chinook stocks are "stay-at-hone" fish in the nearsh.ore 

 ocean. In contrast^ all chinook salmon stocks north of the Rogue 

 River are north migrating to Alaska area marine waters. 



ocean coho salmon catches in Oregon steadily decreased to i960 

 except for a tejaporary rise after World War II, then increased 

 significantly through 1976 to a record high, and then decreased 

 to the present. The increase from i960 to 1976 reflected growing 

 successful hatchery production plvis good ocean conditions 

 nearshore from Washington south to northern California. This is 

 the ocean range of Oregon and northern California coho salmon. 

 Hatchery production has not declined since 1976 and hatchery 

 production methods, disease control procedures, Gt.c. have 

 improved if anything. 



The coho salmon catch decline since 1976 reflects changes in tbe 

 Califomia/AJ.aska Currents which split from the eastward flowing 

 North pacific Drift as it approaches North Ameirica. In recent 

 history through 1975, this main current flow split was south as 

 the California Current. During that period, the Alaska Current 

 was relatively weaker. The strong California Current brought 

 cool, nutrient rich waters along Washington, Oregon and 

 California. Related weather patterns were beneficial to local 

 coastal salmon populations. Good precipitation occurred inland 

 and strong winds out of the northwest resulted in relatively 

 strong effective upwelling. These upwelling events enhanced the 

 cool surface temperature of the water mass and made nutrients 

 even more available in surface waters for phytoplankton. 

 Biological production was good and local salmon survival and 

 growth were good during this period (through 1975). 



Biological production and salsion survival in Alaskan waters were 

 less good through 197S. Since 1976, the Alaska Current flow has 

 predominated and the California Current has been weaker. 

 Biological and salmon production (growth and survival) in Alaska 

 waters has been excellent since 1976. 



In the weaker California Current since 1976, temperature has been 

 warmer (less optimal for salmonids) and the water mass has had 

 less nutrient. Biological production has definitely been 

 nutrient limited in the weaker California Current since 1976. 

 Related weather patterns have bean relatively detrimental to 

 local salnonid fish. Precipitation inland has been lower with 

 several record drought years. Coastal upwelling events have been 

 less frequent and, because of lowered nutrient concentration and 



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