The Effects of Strobe Light and Sound Behavioral Deterrent Systems on Impingement of Aquatic Organisms at PLant Barry, Alabama

Abstract

A hybrid and a sonic deterrent system were both evaluated for their effectiveness to repel fish from becoming impinged in a cooling water intake structure located at Plant Barry (Mobile River, Mobile County, Alabama). The hybrid deterrent system combined strobe lights (300 flashes per minute), sonic sound frequencies (0.4 – 4.0 kHz), and ultrasonic sound frequencies (120 – 130 kHz). The sonic deterrent consisted of random tones at 0.4, 0.63, 1.00, 2.50, and 3.15 kHz. Evaluation of the hybrid deterrent system began 1 May 2006 and ended 6 October 2006. Evaluation of the low frequency sound burst deterrent began 15 November 2006 and ended on 22 December 2006. The sound and light was projected into the forebay of the cooling water intake structure. Effectiveness of the deterrent systems was determined by monitoring impingement numbers. Fish representing 26 taxa were captured during the study. For total fish impingement and for individual fish and non-fish species with sufficient numbers, a split-plot analysis was performed on the sequential treatment (deterrent on) and control (deterrent off) sampling events within each weekly test period. Temporal and environmental variables were considered and accounted for through paired evaluations during individual weeks. The split-plot analysis for the paired treatment evaluation of the total combined and the individual species show that there were no significant reductions in impingement while either deterrent system was in operation. The results of the Hybrid and Sonic fish deterrent testing demonstrated that none of the behavioral stimuli evaluated (sonic sound, ultrasonic sound or strobe lights) were capable of reducing the impingement of freshwater organisms at Plant Barry.