Static Seawater Challenge Test to Measure Relative Stress Levels in Spring Chinook Salmon Smolts

Abstract

Abstract A static seawater challenge test was successfully developed and used to establish a profile of the relative stress levels of spring chinook salmon smolts Oncorhynchus tshawytscha within the smolt collection and transport system at Lower Granite Dam on the Snake River. A major feature of the test was the development of water-to-water transfer techniques designed to assure minimal stress interference associated with sampling and transferring test fish from the freshwater sample sites to the seawater test chambers. The test was used to isolate stresses associated with movement of smolts through the system, with handling and marking procedures, and with holding spring chinook salmon smolts in the presence of predominately hatchery-reared steelhead Salmo gairdneri smolts. The test results clearly indicated a pattern of increasing stress levels as smolts moved through the system. The bypass system, the fish and debris separator complex, and transport by truck were areas where stress levels increased. D...