Influence of pinniped-caused injuries on the survival of adult Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) in the Columbia River basin

摘要: Increasing pinniped abundance in the Pacific Northwest has coincided with population declines of salmon (Oncorhynchus spp.) and steelhead trout (Oncorhynchus mykiss), concentrated predation may affect recovery some threatened endangered salmonid stocks. We used radiotelemetry to evaluate pinniped-caused injury effects on migration survival 17 007 adult Columbia River Chinook tshawytscha) trout. Injuries from pinnipeds were common (mean rate across 29 run-years = 36.5%) most for spring Injury was not consistently associated spawning tributaries, but negative detected. Pinniped-caused rates decreased as annual run sizes increased, indicating density-dependent or saturation effects. Within a run, large fish generally had higher incidence than small fish, suggesting targeted more efficiently captured sm...