翘嘴鳜反季节人工繁殖及苗种培育试验

对来源于鄱阳湖和高邮湖的两个野生翘嘴鳜群体,分别在水泥方池降低温度和减低光照培育以及在池塘网箱按常规培育。结果显示,水泥方池培育的雌鱼,成熟度正常、过熟和流产的比例,鄱阳湖群体为36.7%、40.0%和23.3%,高邮湖群体为40.0%、43.3%和16.7%,而雄鱼精子活力均正常;在池塘网箱培育的雌鱼均已过熟或流产,46.7%的雄鱼精巢完全退化。对成熟度正常和过熟的雌鱼各挑选6尾进行催产试验,正常组的催产率、单位体重产卵量、受精率、孵化率和出苗率均显著高于过熟组。试验共孵化出苗118.7万尾,育成1.3 cm的鱼苗96.3万尾和3~5 cm的鱼种68.1万尾。试验结果表明,采取降低温度和光照,能将翘嘴鳜在江苏地区的人工繁殖期推迟至7月底,从而实现高温期的批量育苗,为鳜鱼的反季节养殖奠定了基础。

Test of anti-season artificial propagation and fry culture of Mandarin fish

Two wild populations of Mandarin fish derived from Poyang Lake and Gaoyou Lake, were bred by way of reducing the temperature and light intensity in concrete ponds, as well as using cages in earth ponds. The resultsSshowed that the proportion of mature, postmature and abortion of the female bred in concrete ponds were 36.7%, 40.0% and 23.3% in Poyang Lake population, and 40%, 43.3% and 16.7% in Gaoyou Lake population, respectively, while the male sperm motility was normal. The female bred in cages of the pond were all postmature or abortion , while 46.7% of the male testis were degraded completely. The inducing trials were carried out in each six female of mature group and postmature group. Inducing rate, egg of the unit weight, fertilization rate, hatching rate and emergence rate of mature group were significantly higher than those in postmature group. The test reached 1,187,000 of larvae, 963,000 of fry 1.3 cm of size and 681,000 of fingerlings 3 cm-5 cm of size. The experimental results showed that the breeding season can be postponed to the end of July by reducing the temperature and light intensity, achieved batch of fry nursing during high temperature period, and laid the foundation for off-season farming in Mandarin fish.