Seasonal and diel passage of juvenile salmonids at John Day Dam on the Columbia River
juvenile, salmonids, John Day Dam, diel movement, Columbia River, chinook, salmon, steelhead, coho, sockeye salmon, night, hydroelectric, hydroelectric dams, dams
Journal or Book Title
North American Journal of Fisheries Management
This paper documents the seasonal and diel movements of seaward-migrating juvenilePacific salmonids (Oncorhynchus spp.) passing John Day Dam on the Columbia River. Duringthe 1987-1989 and 19911993 seasons, the 10, 50, and 90% passage dates each fell within a 2-week period for yearling Chinook salmon (O. tshawytscha), steelhead (O. mykiss), coho salmon(O. kisutch), and sockeye salmon (O. nerka). For subyearling Chinook salmon, the 10 and 90% passage dates varied by as much as 1 month, although the median passage dates occurredwithin a 10-d period. The percentage of fish that passed at night (2200-0600 hours) averaged80.7% for yearling Chinook salmon, 75.7% for subyearling Chinook salmon, 77.9% for steelhead,88.6% for coho salmon, and 78.3% for sockeye salmon. Information concerning the hourly andseasonal movements of juvenile salmonids through hydroelectric dams are essential in makingwise fisheries resource and river flow management decisions.