Morphometric Assessment of Egg Quality for Second Generation of Cultured Small Yellow Croaker, Larimichthys polyactis Broodstock.

The egg quality is a representative limiting factor in developing culture techniques for certain fish species. It is a known predictor of subsequent larval viability, quality, and stress resistance related to aquaculture productivity. Here we tracked egg quality in a second generation of broodstock small yellow croacker, Larimichthys polyactis. Cultured second generation broodstock (3 years old, 600 fishes) was reared in indoor tank (30 tons). We induced natural spawning with increasing water temperature (11.5°C22.0°C) and regulation of photoperiod (9L:15D). We used spawning events from spawning period and monitored basic morphometrics such as: egg viability, egg diameter (ED), oil droplet diameter (OD) and oil droplet volume. Natural spawning of the broodstock was maintained for 23 days. EDs and OD for L. polyactis decreased as the spawning season progressed and water temperature increased. We showed that smaller eggs lead to higher quality with viability, and that using eggs later in the spawning season would lead to better production. In addition, the volume of oil droplet was the strongest factors for prediction of egg viability for cultured second generation of small yellow croaker.