Movement and Habitat Use of Chinook Salmon Smolts, Northern Pikeminnow, and Smallmouth Bass Near the SR 520 Bridge. 2008 Acoustic Tracking Study.

摘要

This study continued and extended research performed in 2007 by the Washington State Department of Transportation (WSDOT) and the U.S. Fish and Wildlife Service (USFWS) to evaluate influence of the SR 520 bridge (the bridge) on behavior and habitat use of Chinook salmon Oncorhynchus tshawytscha smolts and piscivorous fish. Results obtained in 2007 suggested that the bridge was having some influence on migration, movement, and habitat use of Chinook salmon, and that at least one potential predator - smallmouth bass Micropterus dolomieu - often used the bridge as selected habitat. Further study was needed due to high variability in Chinook salmon behavior, uncertainty with regard to important causal factors, and low sample sizes of predators (namely northern pikeminnow Ptychocheilus oregonensis). Results will help guide design and construction of the new bridge to minimize impacts to Chinook salmon.