First maturation and spawning of cultured Oplegnathus fasciatus broodstock in the South China Sea

In early April of 2008, we carried out hormone inducement in 2-year-old Oplegnathus fasciatus broodstocks hatched in May of 2006 in Raoping of Guangdong Province, so as to investgate their reproductive biology for first maturation. Results show that in the South China Sea, it took 2 years for the first maturation with biological minimum size of 245 mm in total length and 610 g in weight, maximum size being 300 mm and 1 450 g for the O.fasciatus broodstocks by complete artificial breeding. Spawning season was from April 10 to July 15 with the peak period from middle April to late June. Being a thermo-dependent spawning type, the breeding temperature of the fish ranged from 20.0~28.8 ℃ with suitable temperature of 20.7~27.6 ℃. Development was synchronous for both sexes and no significant difference was found in size and mature age. Being an annual spawning multiplicity species, thebreeding season of the fish lasted over three months, with total fecundity of 3 180.0104 and maximum daily value of 341.5104. Significant correlation was found among fecundity, quality of fertilized eggs and water temperature. When temperature was stable, the floating rate of eggs maintainedat higher level of 80%~95%. Average diameter of fertilized eggs was (0.8600.023) mm and that of oil globule was (0.1910.009) mm.