|Document Type:||Journal Article|
|Title:||Migratory characteristics of ocean-type chinook salmon, Oncorhynchus tshawytscha, in John Day Reservoir on the Columbia River|
|Author:||Albert E. Giorgi, David R. Miller, Benjamin P. Sandford|
Both stream–type and ocean–type chinook salmon, Oncorhynchus tshawytscha, are found in the Columbia River system. Ocean–type chinook salmon migrate seaward and enter seawater as subyearlings or zero–age juveniles within a year of emergence, whereas stream–type fish reside in fresh water at least one full year before migrating. Yearling streamtype chinook salmon migrate through the mainstem Columbia River and its largest tributary, the Snake River, during the spring months. In contrast, zero–age ocean–type chinook salmon migrate during the summer, but their migration can extend into autumn. Information regarding the migratory behavior of ocean–type chinook salmon in the impounded reaches of the Columbia River is limited. Early research showed that even during high–flow years, large numbers of zero–age ocean–type chinook salmon remained in John Day Reservoir on the Columbia River for a protracted time compared with stream–type chinook salmon.