Effects of a Shad Fishery on Passage of Adult Chinook Salmon through the Oregon-Shore Fishway Ladder at the Dalles Dam - 1996
adult, Alosa sapidissima, American shad, Army Corps of Engineers, chinook, monitoring, Oncorhynchus tshawytscha, salmon, shad, Dalles Dam
Technical Report 99-4
A fishery for American shad Alosa sapidissima at the exit of the Oregon-shore ladder at the Dalles Dam in the spring of 1996 had the potential to disrupt passage of adult chinook salmon Oncorhynchus tshawytscha through the ladder. We evaluated the effects of the shad fishery on passage by monitoring chinook salmon with radio transmitters as they passed through the Oregon-shore fishway. Passage times for 54 radio-tagged chinook salmon that exited the ladder during the period the shad fishery occurred were compared to passage times for 62 radio-tagged chinook salmon that passed the dam prior to the shad fishery. We found no differences in median times for chinook salmon to pass through and exit the ladder before and during the shad fishery using this simple comparison.