养殖黄鲷繁殖特性及诱导产卵的初步研究

A preliminary study on breeding characteristics of cultured Dentex tumifrons and its induced spawning

初步研究了黄鲷(Dentex tumifrons)在人工养殖条件下的繁殖生物学特性,以及诱导产卵.根据养殖记录并辅以鳞片的年轮鉴定,可催产的初次性成熟最小雌性黄鲷为2龄,体长14 cm,体重110 g.按体长区分,20 cm以下的黄鲷雌雄比为1∶0.15; 20 cm以上的黄鲷雌雄比为1∶0.45.每年有二个产卵期分别在3～5月和11月.黄鲷属卵巢发育不同步、分批产卵类型鱼类.黄鲷每个产卵季节的个体怀卵量为5 400-27 000粒,平均15 000粒左右.经催产后产出的黄鲷受精卵平均卵径886 μm,平均油球径184 μm.受精后围卵周隙约16 μm.在水温20.0～22.0 ℃、盐度34的条件下,历时36 h 40 min完成胚胎发育,孵化出仔鱼.在养殖条件下,对3龄以上的黄鲷亲鱼进行人工繁殖比较适宜,诱导产卵的成功率较高.用15 μg+5 mg/kg的LHRH-A2+DOM能有效地催产Ⅵ期性腺黄鲷产卵.水温等环境因子的改变能使黄鲷春季产卵比自然海区的黄鲷提前1～2个月.

This paper describes breeding characteristics of Dentex tumifrons under condition of artificial culture and primary study on induced spawning. According to the records in rearing period and identification of growth ring on squama the minimal age of female Dentex tumifrons for induced spawning was two years old with body length of 14 cm and in body weight of 110 g. It can spawn in March-May and November respectively. Dentex tumifro differ in ovary development and spawning in batches. The fecundity is 5 400 - 27 000 eggs/individual and 15 000 eggs on average. The average diameter of spawned egg is 886 μm and average diameter of oil globule is 184 μm and the gap between membrane and yolk sac after fertilization is 16 μm. The embryo has developed within 36 hours and 40 minutes at water temperature of 20.0 - 22.0 ℃ and salinity of 34 and larva has hatched. Broodstock with more than 3 years old is suitable for artificial propagation with high rate of induced spawning. LHRH-A2 ＋ DOM with 15 μg ＋ 5 mg/kg can effectively induce Dentex tumifron with the Ⅵ stage in gonad development to spawn. The variation of enviroIunental factors such as water temperature advanced its spawning by one or two months in comparison with wild fish.