Preliminary Experiments Using Lights and Bubbles to Deflect Migrating Young Spring Salmon
bubbles, canal, downstream fish passage, fingerlings, fish diversion, flashing light, Fronts, migration, night, salmon, trout
Journal or Book Title
Journal of the Fisheries Research Board of Canada
Experiments to deflect young spring salmon during their night-time migration by means of a beam of light and/or a "wall" of bubbles were conducted in a canal near Courteney, B.C. Under natural conditions (by the use of hoop nets) no significant difference existed in the respective catches of spring salmon underyearlings moving downstream. However, a significant difference was obtained when a narrow beam of light was directed into the water at a downstream angle in front of one net. A reduction to about 1/3 the expected catch resulted with either continuous or flashing light. The "wall" of bubbles, in a similar position, did not reduce the catch. Cut-throat trout fry and hatchery-reared Kamloops trout fingerlings were not deflected under these conditions.