葛洲坝水利枢纽工程对坝下江段胭脂鱼性腺发育及自然繁殖的影响

A EFFECT OF THE GEZHOU DAM KEY WATER CONTROL PROJECT ON SEXUAL GLAND DEVELOPMENT AND NATURAL SPAWNING OF CHINESE SUCKER MYXOCYPRINUS ASIATICUS IN THE DOWNSTREAM BELOW THE DAM

本文研究了大坝兴建后,阻隔在坝下江段的胭脂鱼性腺发育状况。结果表明,只要达到性成熟年龄(雌鱼 7龄、雄鱼 5龄),胭脂鱼性腺不仅能在坝下江段正常发育成熟,而且能自然繁殖。产卵场主要分布在有砾石或礁板石水流较紊乱的江段。自然繁殖主要与水温有关。产卵期2月至4月。文中同时讨论了坝下江段胭脂鱼保护等问题。

The results show that the sexual gland of chinese sucker blockedby tbe dam can develop and maturate normally in the downstream. Sexual maturityis reached at age 7^+ for females, Over 5^+ for males. The ovaries of stage Ⅱ (inclu-ding stage Ⅱ after spewning), Ⅳ. Ⅴ, Ⅵ and the testes of stage Ⅱ,Ⅲ(includingstage Ⅲ after spawning), Ⅳ,Ⅴ,Ⅵ were collected. Meanwhile, the microscopicalstructure characteristics of ovaries and testes were observed. Altogether 138 specimens were collected in 1983--1990.55 of them are matu-rity, constituting 39.86% of the total and 83 of them are immature, constituting60.14%. The mature females are 82--110cm in TL, 94.50±7.21cm on average; 9.2--20kg in weigat, 14.39±3.46kg on average. While the males 76.5--108cm in TL,92.67±7.69cm on average; 8--18.25kg in weight, 12.28±2.48kg on average. The females collected at the age of 7--14 and males 5--14. Sexual ratio of female to maleis 1: 1.39. Absolute fecundity is from 215,000 to 422, 500 eggs, average fecundity is onthe order of 286, 800 eggs per females; relative fecundity 13.48--21.66 egg/g, ave-rage 16. 89egg/g. In late autumn and early winter, the adults move from the middle and lowerreaches of the river to the section below the dam, and often stay in deeper water.By spring, from the end of February to the end of April, the parents move intosome areas where current is swift and gravel covers the bottom for spawning.Spawning is chiefly related to temperature and most occurs in the fine morning.The problems of protective for chinese sucker in the lower reaches of the dam arediscussed as well.