Passage of Salmonids Through a Darkened Fishway
day/night samples, fish passage, light conditions, orifices, pool and weir, rate of passage, salmonids, steelhead
Fisheries No. 300
US Fish and Wildlife Service
Special Scientific Reports
An experiment to produce specific information on rate of ascent of salmonids through a darkened fishway was conducted in a short, pool-and-overfall fishway without submerged orifices. The fish (98 percent steelhead - Salmo gairdneri) negotiated the 6-pool fishway significantly faster in near-total darkness than in light conditions approximating a bright, cloudy day.