Responses of fish to a strobe light/ air-bubble barrier

Abstract

The responses of selected freshwater ( Alosa pseudoharengus, Osmerus mordax, Dorosoma cepedianum) and estuarine ( Morone americana, Leiostomus xanthurus, Brevoortia tyrannus) species to air bubbles alone, strobe light alone, and a combined strobe light/ air-bubble barrier were investigated under laboratory conditions. Gizzard shad, alewife and smelt avoided an air-bubble barrier. Avoidance response varied with air-bubble spacing and illumination. All species tested exhibited avoidance behavior to strobe lights, which varied with current velocity, strobe flash rate, and acclimation of fish. Increased avoidance was evident for most species when strobe lights were combined with air bubbles as an exclusion barrier. A combined strobe light/ air-bubble scheme shows potential for application in fish management schemes. Strobe light is more effective than continuous light.