长江大鳍鱯的人工繁殖

Parent fish cultivation in ponds andartificial propagation of Mystus macropterus

本文对长江大鳍亲鱼的池塘培育和人工繁殖技术进行了研究。１９９２年～１９９４年期间，采用池塘混养技术，将长江野生大鳍引入池塘进行驯化和培育，连续２年获得成熟亲鱼并进行人工繁殖。在池塘环境中，大鳍雌亲鱼成熟率分别为８１８％和７０６％，雄亲鱼分别为１００％和９３５％。采用多种催产药物混合注射的催产方法，可以得到较好的催产率。大鳍人工繁殖适宜的催产剂量是雌鱼每ｇ体重注射ＬＲＨ－Ａ０３～０５μｇ、ＤＯＭ００３～００５ｍｇ和ＨＣＧ５～１０ＩＵ，雄鱼减半或同量。水温２４～２６℃时，催产效应时间为１２～１３ｈ。受精卵在水温２７～２９℃时需５３～５５ｈ孵化出膜。大鳍人工繁殖受精率不高与其雄鱼精巢特殊的组织结构有关。

The parent fish were collected from the Yangtze River. They were domesticated and cultivated in ponds. The results of domestication show that the sexual gland of parent fish (female and male) can develop normally in ponds. The rate of maturation for female gonad is 81.8% in 1993 and 70.6% in 1994, respectively. But that for male gonad is 100% in 1993 and 93.5% in 1994, respectively.The artificial spawning of mature female and male fish was successful. They were artificially induced spawning by injection with the mixture of LRH-A with DOM and HCG. The dosage of LRH-A、DOM and HCG for female are 0.3～0.5 ug/g, 0.03～0.05 mg/g and 5～10IU/g body weight, respectively. The dosage for male is half of that for female. 12～13h after injected the female fish spawned at water temperature between 24～26℃. The fry were hatched out after 53～55h of incubation at water temperature between 27～29℃. The observation of 5-day-old larvae demonstrates that the digestive organs developed incomplately and the yolk sac is nearly absorbed.