"We used a previously published method to relate substrate composition at seven fall chinook salmon spawning sites in the Snake River implicitly to emergence success. We used dome suction to sample substrate at four spawning sites in the upper reach of Snake River and three in the lower reach. Mean percent fines <6.4 mm and <0.85 mm were less in upper reach samples than in lower reach samples. In laboratory tests, mean emergence success decreased from 47 to 10% as the mixtures of percent fines <6.4 mm and <0.85 mm increased in substrate mixtures. A regression equation developed from the laboratory data to predict mean emergence success from mean percent fines <6.4 mm and <0.85 mm had an r2 value of 0.94. Predicted emergence success based on substrate composition in the Snake River ranged from 46 to 48% for sites in the upper reach, and from 29 to 47% for sites in the lower reach."
"We used a previously published method to relate substrate composition at seven fall chinook salmon spawning sites in the Snake River implicitly to emergence success. We used dome suction to sample substrate at four spawning sites in the upper reach of Snake River and three in the lower reach. Mean percent fines <6.4 mm and <0.85 mm were less in upper reach samples than in lower reach samples. In laboratory tests, mean emergence success decreased from 47 to 10% as the mixtures of percent fines <6.4 mm and <0.85 mm increased in substrate mixtures. A regression equation developed from the laboratory data to predict mean emergence success from mean percent fines <6.4 mm and <0.85 mm had an r2 value of 0.94. Predicted emergence success based on substrate composition in the Snake River ranged from 46 to 48% for sites in the upper reach, and from 29 to 47% for sites in the lower reach."