Regulation of water temperature, feeding frequency and larval stocking density leads to shorter duration of larval stage of Japanese eel Anguilla japonica

Abstract

Under the current rearing conditions (control) of eel larvae, the larval period of Japanese eel Anguilla japoni- ca in captivity is longer than that in nature. In this study, we first investigated the effects of feeding frequency and rearing temperature on larval growth and survival. Based on these results, we demonstrated that eel larvae grew faster than the control by three modifications: rearing at higher temperature, feeding at higher frequency and decreasing the number of rearing larvae by dividing them into several rearing tanks. As a result, we obtained an average larval period of eel of 210 days from hatch to completion of metamorphosis, in contrast to 303 days in the control. These results suggest that careful modifications of rearing conditions can shorten the larval period of eel.