Effect of Acoustic Conditioning for Feeding on Adaptation to Natural Environment in Released Red Sea Bream, Pagrus major

Abstract

Young red sea bream fed with artificial diet under acoustic conditioning for 13 days in floating net cages were released into the natural water near the net cages of the Hiroshima Pref. Fish. Exp. Station on October 3, 1989. Thereafter the fish were fed under the acoustic conditioning. The fish recaptured from the natural water were subjected to determination of physiological condition in terms of biological characteristics and body constituents.
Red sea bream are suggested to exhaust their energy stores during perturbed condition resulting from environmental changes. However, any negative phenomenon was not found in the fish in regard to energy retention, which was probably active feeding under the acoustic conditioning. The released fish accumulated sufficient triglyceride reserves during autumn to meet the demand for wintering. The acoustic feeding conditioning might be available for increasing stocking efficiency as to adaptation to the new environments.