Only hatchery-produced fish, identified by a missing fin on their backs, can be kept in any of Idaho's salmon seasons. Fisheries biologists assume 10 percent of the wild fish caught and released eventually die from injuries and infections. We want to be conservative to protect the listed fish. The 10 percent hooking mortality rate on spring and summer chinook is a number generally used throughout the Columbia River Basin, according to Kiefer. Summer chinook run a higher risk of mortality from wounds they incur because water temperatures are higher while they are in fresh water.
Warmer water can make infections spread more quickly and generally tax fish more than cold water.
By comparison, biologists use a hooking mortality of just 6 percent on fall run steelhead. The spring chinook fishing season on the Little Salmon, North Fork of the Clearwater and the Clearwater River closed at the end of fishing hours Tuesday. But salmon fishing remains open on the Lochsa and South Fork of the Clearwater rivers. Biologists at the department continue to be pleased at the strength of the sockeye run, the most imperiled of Idaho's salmon. Historically, about 50 percent of the sockeye counted at the dam make it to Redfish, Atluras and Pettit lakes in the Stanley Basin.