populations ranging as high as 100,000 or more showed that a population with a disease incidence of 58 or greater can be detected from a sample of 60 fish (Ossiander and Wedemeyer 1973).Health survey samples of 60 fish were taken at the hatcheries,and held in circular tanks in fresh water at Manchester.In most cases,the tissue and blood samples were collected within 24 hours after arrival at Manchester. Sampling for Physiology Plasma Electrolytes Sodium,potassium,and chloride ion levels in plasma were determined for the Wells Dam Hatchery steelhead,Salmo gairdneri,and Big Creek Hatchery fall chinook salmon,Oncorhynchus tshawytscha,near the time of release.Profiles of plasma electrolytes of the Tucannon and Chelan Hatchery steelhead and Carson Hatchery spring chinook salmon were determined in fresh water and during seawater culture at Manchester. Plasma sodium and potassium values were determined by atomic absorption spectrometry and chlorides with a chloridometer. Gill Na+-K+ATPase During 1979,selected stocks of fall and spring chinook salmon and steelhead trout being reared for release at state and federal hatcheries in the Columbia River drainage were monitored for changes in gill Na+-K+ ATPase to evaluate the state of smoltification at release From tagged releases,we determined the relationship between the state of smoltification at release and length of migration time from the hatchery to the estuary. At approximately 2-week intervals during the spring and summer of 1979,30 fish were removed by dip net from representative ponds or raceways at Tucannon,Carson,Leavenworth (Chelan),and Big White Salmon Hatcheries.populations ranging as high as 100,000 or more showed that a population with a disease incidence of 5% or greater can be detected from a sample of 60 fish (Ossiander and Wedemeyer 1973). Health survey samples of 60 fish were taken at the hatcheries, and held in circular tanks in fresh water at Manchester. In most cases, the tissue and blood samples were collected within 24 hours after arrival at Manchester. Sampling for Physiology Plasma Electrolytes Sodium, potassium, and chloride ion levels in plasma were determined for the Wells Dam Hatchery steelhead, Salmo gairdneri, and Big Creek Hatchery fall chinook salmon, Oncorhynchus tshawytscha, near the time of release. Profiles of plasma electrolytes of the Tucannon and Chelan Hatchery steelhead and Carson Hatchery spring chinook salmon were determined in fresh water and during seawater culture at Manchester. Plasma sodium and potassium values were determined by atomic absorption spectrometry and chlorides with a chloridometer. Gill Na+-K+ ATPase During 1979, selected stocks of fall and spring chinook salmon and steelhead trout being reared for release at state and federal hatcheries in the Columbia River drainage were monitored for changes in gill Na+-K+ ATPase to evaluate the state of smoltification at release. From tagged releases, we determined the relationship between the state of smoltification at release and length of migration time from the hatchery to the estuary. At approximately 2-week intervals during the spring and summer of 1979, 30 fish were removed by dip net from representative ponds or raceways at Tucannon, Carson, Leavenworth (Chelan), and Big White Salmon Hatcheries. 4