Estuarine fish responses to strobe light, bubble curtains and strobe light/bubble-curtain combinations as influenced by water flow rate and flash frequencies

This study examined the possible use of strobe lights and strobe light/bubble-curtaincombinations as behavioral guidance systems for estuarine fish. White perch (Morone americana), spot (Leiostomus xanthurus) and Atlantic menhaden (Brevoortia tyrannus) were tested in a behavior experimental tank for avoidance to strobe lights, bubble curtains and strobe light/bubble-curtain combinations at different water flow rates, strobe flash frequencies and light acclimations. Percentage avoidance of strobe light ranged from 8 to 36% for white perch, from 8 to 100% for spot and from 8 to 68% for menhaden, depending on the conditions tested. χ² analyses indicated significant (P < 0.05) avoidance by white perch at most flash rates with a 0.2 ms^-1 flow rate, and at 120 and 300 flashes min^-1 with 0.3 and 0.5 ms^-1 flows. Spot had significant avoidance for all flash rates at the 0.2 ms^-1 flow, and for 300 and 600 flashes min^-1 at water velocities of 0.3 and 0.5 ms^-1. All species showed little avoidance of bubble curtains. Avoidances of 3-58% for white perch, 21-85% for spot and 9-81% for menhaden were obtained with the strobe light/bubble-curtain combinations. χ² analyses indicated significant avoidance for most conditions at 0.2 and 0.5 ms^-1 flows for spot and menhaden. White perch had significant avoidance for most conditions at the 0.2 ms^-1 flow, but no avoidance at 0.5 ms^-1. The strobe light and strobe light/bubble-curtain combinations elicited best avoidance results at flash rates of 300 min^-1 or greater and low flow rates. Strobe lights show promise as a guidance system for estuarine fish.