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Effect of stocking density and feeding regime on larval growth, survival, and larval development of Japanese flounder, Paralichthys olivaceus, using live feeds

Geng, Jia, Belfranin, Christina, Zander, Ian A., Goldstein, Emma, Mathur, Shubham, Lederer, Blanka I., Benvenuti, Riccardo, Benetti, Daniel D.
Journal of the World Aquaculture Society 2019 v.50 no.2 pp. 336-345
Paralichthys olivaceus, feed rations, hatching, larvae, larval development, live feeds, metamorphosis, photographs, rearing, stocking rate, survival rate, tanks, water quality
This research examined the effect of initial stocking density and feeding regime on larval growth and survival of Japanese flounder, Paralichthys olivaceus. Larval rearing trials were conducted in nine 50‐L tanks with different initial stocking densities combined with different feed rations (20 larvae/L with standard feed ration [LD], 80 larvae/L with standard feed ration [HD], and 80 larvae/L with four times the standard feed ration [HD+]). Larvae were stocked on 0 days posthatch (DPH) following hatching of the fertilized embryos. Larval total length (TL), survival rates, and final densities were observed on larval settlement (32 DPH) to evaluate larval rearing performance. At 32 DPH, there were no significant differences (p > .05) in TL or survival rates between the LD (46.5 ± 17.0%) and HD+ (40.3 ± 9.4%). The TL and survival rate of HD (23.1 ± 3.5%) were significantly lower than that of LD and HD+ (p < .05). However, the larval density of HD was significantly higher than that of LD (p < .05). HD+ achieved the best larvae production (32.27 ± 7.51 larvae/L), supported by sufficient food source, high water exchange, and proper water quality management (routine siphoning, surface skimming). The larval‐rearing protocols and larval development from hatching to metamorphosis is described in detail, with corresponding photographs taken during the experiment.