A Preliminary Study of Osteochilus spilurus (Bleeker 1851) Domestication: Sex Identification and Bio-reproductive Characters

摘要

Background and Objective: Understanding of reproductive biology performance in fish is one of the essential stages in the domestication program. The research aimed to determine sex and bio-reproductive characters of Osteochilus spilurus to identify brood-stock candidates and its maturation level. Materials and Methods: A total of 100 fish samples were collected from Lenggang river, East Belitung, Sumatera. Fish were acclimatized and reared in an indoor rectangular tank and fed with commercial crumble feed over six months. We identified 5 females and 3 males which were predicted as sexually mature fish. The female fish were about 4.2±0.1 cm in length dan 2.25±0.59 g in weight, while the males were around 4.3±0.7 cm in length and 1.85±1.00 g in weight. Sex identification was determined based on the external characteristic such as bulging soft abdomen, urogenital, body size and color. Observation of biological characters were carried out to measure length (cm), weight (g), gonad (g), gonadosomatic index [GSI] (%), oocyte diameter (mm) dan fecundity (egg/fish). Results: The fish male has slimmer body shape, a attened abdomen and darker in color around the dorsal area, while the female is more rounded ventrally, brighter and golden-green. The mature male and female brood-stock have GSI values of 11.53±2.17%) and 12.37±2.63%, respectively. The average fecundity of eggs each specimen was about 736±87 eggs/fish with oocytes diameter about 1.0±0.2 mm. There was a positive correlation between fecundity and weight of fish. Conclusion: The identification sex of Osteochilus spilurus can be determined based on external observation of body shape and color . Swollen belly shape, gonad condition and egg diameter are essential characteristics to predict a sexually mature brood-stock.