The Effect of Electric Lights Upon the Upstream Passage of Three Species of Adult Salmon Through the University of Washington Fishladder




adult, avoidance behavior, chinook, day/night samples, fish passage, fish ladder, light conditions, night, salmon, screens, silver salmon, sockeye salmon, University of Washington, upstream, upstream passage


A 64-foot approach to the University of Washington fishladder was wired so that electric lights underneath the screen could be turned on and off on alternate nights during the adult salmon runs. The number of adult sockeye, chinook and silver salmon ascending the ladder was recorded daily. All species displayed a statistically significant preference for entering during the night over the day, and for dark nights over light nights. Sockeye were significantly more sensitive to light than either silvers or chinooks, with no significant difference between the latter two species.

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