Experiments on the use of sound as a fish deterrent

This report describes a series of experimental studies into the potential use of acoustic stimuli to deter fish from water intakes at thermal and hydroelectric power stations. The aim was to enlarge the range of candidate signals for testing, and to apply these in more rigorous laboratory trials and to a wider range of estuarine and marine fish species than was possible in previous initial preliminary studies. The trials were also required to investigate the degree to which fish might become habituated to the sound signals, consequently reducing their effectiveness. The species of fish which were of interest in this study were the Atlantic salmon (Salmo salar), sea trout (Salmo trutta), the shads (Alosa fallax, A. alosa), the European eel (Anguilla anguilla), bass (Dicentrarchus labrax), herring (Clupea harengus), whiting (Merlangius merlangus) and cod (Gadus morhua). All of these species are considered to be of conservation and/or commercial importance in Britain today and are potentially vulnerable to capture by nuclear, fossil-fuelled and tidal generating stations. Based on the effectiveness of the signals observed in these trials, a properly developed and sited acoustic fish deterrent system is expected to reduce fish impingement significantly at water intakes. Field trials at an estuarine power station are recommended. (author)