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本文报道了自1979年以来河鳗人工繁殖研究的基本情况,包括亲鳗催熟、催产以及胚胎发育和培育等试验内容。 试验结果表明,在人工催熟和水温逐渐升高的条件下,大部分亲鳗在4月上旬至5月中旬性腺成熟。从1974年至1978年总的产卵受精率为8.4%(其中流卵和产死卵者不计在内)。亲鳗自然产卵的时间一般在凌晨4时至6时20分之间,水温在18.5-24.5℃范围。产卵行为较特殊,产卵前发情时,雄鳗和雌鳗先后由池底阴暗处游至水表,沿池边环游追逐,最后在较小范围内急游产卵授精,产毕又回至池底。海水盐度在23-29.8‰范围,均能产卵受精,并孵出鳗苗。 孵出后头两天的仔鳗悬于水表;第3天的仔鳗,卵黄囊大部分吸收,消化道全通,在肠内开始发现食物团,肠道内有强烈的纤毛运动,鱼体开始悬于水中,有极缓慢的下沉和上升;第4天眼球出现黑色素,晶体透明,上、下颌能启闭,有四对牙齿;第5天,肠道有蠕动波,出现肝脏原基,静止时侧卧水底;第14天,仔鳗在微流水中能不断游动,在静水中常处于水底。仔鳗养至第19天,存活434小时。
This article reports on the basic situation of artificial breeding of river eels since 1979, including the experiments of ripening, oxytocin and embryo development and breeding. The results showed that under the conditions of artificial ripening and water temperature rising, most of the pro-eel matured in the gonads from early April to mid-May. From 1974 to 1978, the total fertilization rate was 8.4% (excluding those who had oviposited or died). Natural eel spawning time is generally between 4 am to 6:20, the water temperature in the 18.5-24.5 ℃ range. Spawning behavior is rather special, spawning before estrus, the male eel and female eels swim from the bottom of the pool to the water meter, chase along the edge of the pool, and finally in a small range of emergency spawning insemination, the production is completed and back to Bottom of the pool. Sea salinity in the range of 23-29.8 ‰, can spawn fertilization, and hatched eel seedlings. The first two days of hatching eel erected in the water meter; the first three days of eel, yolk sac most of the absorption, all-pass digestive tract, began to find food in the intestine, the intestine has a strong ciliary movement, the fish began to hang In the water, there is a very slow sink and rise; the first 4 days the eye appears melanin, the crystal is transparent, the upper and lower jaw can be opened and closed, with four pairs of teeth; the first 5 days, the intestine has peristaltic waves, the liver primordia, static On the fourteenth day, Abeille eel can keep swimming in the microfluid, often in the bottom of still water. Aberdeen feeding until the 19th day, survive 434 hours.