SOUND PRESSURE AND FREQUENCY CONDITIONS WHEN ANGUILLA JAPONICA AVOIDS

Abstract

 One of the reasons for the decrease in the Anguilla japonica population is the straying into the intakes of dams and weirs, and a method using avoidance behavior from sound is used as a preventive measure. Studies have been conducted on the effects of sound on the avoidance characteristics of eels, but no studies have been conducted on Anguilla japonica. In this study, the effects of sound pressure levels and frequencies of 91 to 126 dB re 1 μPa and 20 to 300 Hz, respectively, on the avoidance characteristics of Anguilla japonica were investigated in a circular pool of stationary fluid. As a result, Anguilla japonica tended to avoid sounds with frequencies of 150 to 200 Hz at underwater sound pressure levels between 91 and 126 dB re 1 μPa. In addition, the swimming speed of Anguilla japonica tended to increase in the frequency range of 150 to 200 Hz. Therefore, it is possible that Anguilla japonica avoid sounds with frequencies of 150 to 200 Hz near the water intake, preventing Anguilla japonica from straying into the water.