Saturday, July 25, 2009

Mortality Spikes for Outmigrant Chinook at McNary


McNary Dam is a notorious fish killer on the Columbia River. With the recent heat wave in the Pacific Northwest mortality of outmigrant fall chinook spiked to over 17% last week. Monitoring the juvenile survival using PIT tags managers believe the high mortality to be due to heat shock as the juvenile fish pass from cold water spillways into warm water areas. The period of high mortality was well above the legally mandated 6 percent acceptable mortality, forcing managers to increase the amount of spill to reduce mortality through McNary. Among the stocks affected are ESA listed Snake River Fall Chinook. See the full story at the CBB

No comments: