Abstract: Abrupt temperature drop in seawater could be caused by varied thermal effluents from coastal power plants, seasonal change, cold wave, etc., leading to different degrees of cold shock consequences on poikilotherm, like fish. In this study, we mimicked abrupt temperature drop events with several amplitudes to discuss the cold shock consequences on the incubation, mortality, abnormality rates of Larimichthys crocea eggs and larvae. As results, the three days old larvae were more sensitive to abrupt temperature drop than eggs. Within the optimal temperature, when temperatures decreased rapidly from 22 ℃ to 19 ℃ or to 16 ℃, the hatching success and mortality rates of eggs had no obvious change, but the embryonic and larval developments were slower, and the larval mortality rates were accelerated. When temperatures dropped acutely from 22 ℃ to 13 ℃ and 10 ℃, below the lower lethal temperatures, lethal consequences were caused on fish eggs and larvae, with high mortality rates (84.6%-100% and 72.1%-98.2%, respectively). Thus, we speculated that could shock would cause lethal consequences on the early stage of L. crocea and lead adverse impact on stock replacement and age structure of L. crocea when temperature dropped acutely below the lower lethal temperatures.

Key words: abrupt temperature drop, Larimichthys crocea, fish eggs, fish larvae, thermal effluents, cold shock