Homing in Sockeye and Chinook Salmon Transported around Part of Their Smolt Migration Route in the Columbia River

Abstract

Abstract We evaluated homing efficiency of adult Pacific salmon Oncorhynchus spp. that had been transported as smolts around portions of their migration route in the Columbia River. We captured smolts of sockeye salmon O. nerka and spring chinook salmon O. tshawytscha at Priest Rapids and Wanapum dams and released marked control groups at the left bank of the Columbia River, just downstream from Priest Rapids Dam (river kilometer, rkm, 639 from the mouth of the river). In 1984–1986, we transported marked sockeye and chinook salmon smolts in trucks to the river edge downstream from Bonneville Dam (rkm 205). In 1987–1988, we compared truck transport of sockeye salmon with combined transport by truck to McNary Dam (rkm 467) and by barge from McNary Dam to the middle of the river downstream from Bonneville Dam. We compared ratios of transported to control Pacific salmon observed as adults at Bonneville Dam (2.55 for sockeye salmon, 2.43 for chinook salmon) and at Priest Rapids Dam (1.29 for sockeye salmon, 0....