Two feeding trials were carried out to determine the optimum feeding rates in juvenile olive flounder, Paralichthys olivaceus, at the optimum rearing temperature. Fish averaging 5.0 ± 0.11 g (mean ± SD) in experiment 1 and 20.2 ± 0.54 g (mean ± SD) in experiment 2 were fed a commercial diet at the feeding rates of 0%, 3.0%, 4.0%, 4.25%, 4.5% and 4.75% body weight (BW) day−1 and satiation (5.52% BW day−1) in experiment 1 and 0%, 1.0%, 2.0%, 3.0% and 3.5% BW day−1 and satiation (4.12% BW day−1) in experiment 2 at 20 ± 1 °C. Both feeding trials lasted for 2 weeks. Results from experiment 1 indicated that weight gain (WG) and specific growth rate (SGR) of fish fed to satiation were significantly higher than those of fish fed at other feeding rates while feed efficiency (FE) and protein efficiency ratio (PER) of fish fed at 4.25% BW day−1 were significantly higher than those of fish fed to satiation and fish fed at 3.0% BW day−1 (P < 0.05). In experiment 2 WG, SGR and PER leveled out after the feeding rate of 3.5% BW day−1 whereas FE reached a plateau at 3.0% BW day−1. anova of FE indicated that the optimum feeding rates in 5.0 and 20 g juvenile olive flounder could be 4.25% and 3.0% BW day−1, respectively. Broken line analysis of WG suggested the optimum feeding rates of 5.17% and 3.47% BW day−1 in 5.0 and 20 g fish, respectively. Therefore, these results indicated that the optimum feeding rates could be >4.25 but <5.17% BW day−1 for 5.0 g, and it could be >3.0 but <3.47% BW day−1 for 20 g size of juvenile olive flounder at the optimum rearing temperature.

: A 32 factorial experiment was conducted to determine the effects of dietary protein and lipid levels on the growth and body composition of juvenile far eastern catfish. Six diets were formulated to contain three levels of protein (20%, 30% and 40%) and two levels of lipid (9% and 17%). Triplicate groups of fish (initial body weight of 7.6 g) were hand-fed to apparent satiation for 66 days. Final mean weight was improved with increasing dietary protein and lipid levels, and the highest final mean weight was observed in fish fed the 40/17 (% protein/% lipid) diet. No significant difference was observed in final mean weight for fish fed between 30/17 diet and 40/9 diet. Feed efficiency of fish fed the diets containing over 30% protein levels with 9% and 17% lipid levels were significantly higher than those of fish fed the 20% protein levels. Feed efficiency of fish fed the 30/17 diet was not significantly different from that of fish fed the 40/9 diet or 40/17 diet. Feed efficiency and protein efficiency ratio of fish fed the 20% protein diets with 17% lipid level were significantly higher than those of fish fed 9% lipid diet. Daily feed intake of fish tended to decrease with increasing dietary protein and lipid levels. Moisture content of whole body in fish fed the 9% lipid diets was significantly higher than that of fish fed the 17% lipid diets at the same protein level, but the opposite trends were found for crude lipid content. Significant effects of dietary lipid were observed for most fatty acids, according to their relative values in the diets. The results of this study suggest that the protein requirement for maximum growth of juvenile far eastern catfish may be higher than 40%, and an increase of dietary lipid level from 9% to 17% can improve growth and feed utilization.

The seven-band grouper (Epinephelus septemfasciatus) is an important fishery resource of a target for prospective aquaculture diversification and maintenance of stock quality is thus important. To explore the sustainability of fry production, genetic variations in 83 sevenband groupers from two broodstock and offspring populations of a hatchery strain were analyzed using 13 polymorphic nuclear microsatellite DNA loci; 133 alleles were identified. Allelic variability ranged from 4 to 18 in the broodstock and from 3 to 11 in the offspring. The average observed and expected heterozygosities were 0.669 and 0.734 in broodstock and 0.674 and 0.649 in offspring, respectively. Although no statistically significant reductions in heterozygosity or allelic diversity were evident in offspring, considerable loss of rare alleles was apparent. The broodstock and offspring populations exhibited significant genetic differences (F ST = 0.033, P \ 0.001) indicating that genetic drift has likely promoted differentiation between the two populations, which may have negative effects on sustainable fry production. Therefore, genetic variations between broodstock and offspring should be monitored, and inbreeding should be controlled, to ensure the success of commercial breeding programs. Our data provide a useful genetic basis for future planning of sustainable culture and management of E. septemfasciatus in fisheries.

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