The use of strobe lights and strobe light-bubble curtain combinations were evaluated as behavioral guidance systems to reduce impingement via avoidance behavior by estuarine fish. White perch (Morone americana), spot (Leiostomus xanthurus) and menhaden (Brevoortia tyrannus) were tested in an experimental flume for avoidance to strobe lights, bubble curtains and strobe light-bubble curtain combinations at different water velocities, strobe flash rates and light acclimation (light and dark). The possible accommodation of fish to strobe light was also tested using a microcomputer and on-line biomonitoring chamber examining alterations in breathing rates over time. Avoidance of strobe light ranged from 8-36% for white perch, 8-100% for spot and 8-68% for menhaden depending on the conditions tested. Statistical analyses indicated significant 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 under most conditions. Menhaden had significant avoidance for all flash rates at 0.2 ms-1 flows and for 300 and 600 flashes min-1 at flows of 0.3 and 0.5 ms-1. All species exhibited little avoidance of bubble curtains alone. Strobe light-bubble curtain combinations had avoidance results of 3-58% for white perch, 21-85% for spot and 9-81% for menhaden. Spot and menhaden exhibited significant avoidance for most conditions at 0.2 and 0.5 ms-1 flows. White perch had significant avoidance for most conditions at 0.2 ms-1 flows, but no avoidance at 0.5 ms-1. The biomonitoring system indicated that little, if any, accommodation took place during 24 h. Strobe light and strobe-bubble curtain combinations elicited the highest avoidance results at flash rates ≥300 min-1 and low water velocities. Strobe light systems may reduce impingement rates but must be evaluated on site specific needs and conditions.
All Science Journal Classification (ASJC) codes
- Geography, Planning and Development
- Management, Monitoring, Policy and Law