Effects of compressed seasonally changing day‐length cycles on spawning performance, production of viable eggs and levels of vitellogenin in plasma in female yellowtail snapper Lutjanus argentiventris

Abstract

Reproduction in yellowtail snapper Lutjanus argentiventris took place after compressing the seasonally changing day length into a 3 month period applied during two consecutive winters, with the longest and shortest days in December and February, respectively. During the first winter, there was no clear peak of days of spawning and the production of viable eggs was similar from the longest and throughout the decreasing day lengths until reproduction ceased. The level of plasma vitellogenin rose abruptly to a maximum concentration during the increasing day length and then decreased dramatically before the longest day length. During the second winter, a clear peak in the number of days of spawning and the highest production of viable eggs occurred around the longest day length. These results showed that it is feasible to synchronize day length between winter-induced and natural summer and autumn reproduction to produce eggs and larvae during the year.