Determining the Effect of Different Ecological Conditions on theMaturation of Rabbitfish (Siganus guttatus)

Abstract

A study aimed at the rabbitfish Siganus guttatus (Bloch, 1787), the reproductive ability of one economically important marine and brackish fish in Giang lagoon systems and marine Asia. The future expectations of mariculture development were decided in Vietnam. The region had enough fingerlings for intensive culture and polyculture to contribute to environmental conservation and sustainability. There were 3 experiments in 3 different ecosystems for fish culture and maturity by feeding a commercial feed and finding suitable areas for the maturing period. The results showed that the growing fish kept in cages on the lagoon had the best growth and rate maturity, much higher than fish in cages of shrimp ponds and plastic bottom ponds, as showed a much bigger size of body, 610 g/head for females and 542 g/head for males, while other culture more 500/head, especially after 3 months of feeding, more than 20% matured for females, they reached more 50% at 6 months feeding. The length at first sexual maturity was 28.87 to 31.20 cm and 27.47 to 29.20 cm for females and males, respectively. The potential ova diameter is from 405 to 483 µm, P < 0.05; the benefit for spawning, gonads maturity stages, with GSI (gonadal-somatic index), 3.03 to 4.53 were opportunities for the spawning season, ova diameter and fecundity and the gonadal-somatic index were differed significantly (P < 0.05) males and females. This result showed the maximum (peak), and all fish can mature and get to spawning. In conclusion, different ecosystems impacted maturity and spawning during the moon season.