Blueback herring respond to brief ultrasonic stimulus sounds

Abstract

Captive schools of Blueback Herring (Alosa aestivalis) were subjected to 1-h long treatments of short 118-kHz sounds applied from a piezoelectric transducer submerged outside a vinylized canvas pen that was suspended in Richard B. Russell Reservoir on the Savannah River. In the experiments reported here, the effect on herring distrbution of 3.8-ms long bursts at 13 repetitions/s (5% duty cycle) was compared to the effect of both another 118-kHz sound treatment (with a different duty cycle but the same source level) and a sound-off treatment. Each experiment compared herring distributions in the pen with the three treatments applied in a cross-over design. The experiments lasted six days each with six 1-h treatments per day. All of the several combinations of pulse duration and repetition rate contained the herring near the end of the pen farthest from the sound source but hour-long continuous wave treatments produced only a brief startle response at stimulus onset. [Work supported by U.S. Army Engineer District, Savannah of the U.S. Army Corps of Engineers.]