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本文报道兴建中的长江天鹅洲“四大家鱼”天然种质资源库中鲢、鳙、草鱼与青鱼的生长、死亡特性和资源数量变动规律。对这4种鱼生长参数值的比较分析表明,天鹅洲故道鲢、鳙、草鱼、青鱼基本维持了长江天然群体的优良生长特性。1991年度,故道渔获量为71.8万公斤,其中“四大家鱼”产量8.8万公斤。鲢、鳙、草鱼、青鱼的死亡率分别为0.66、0.77、0.86、0.86。”四大家鱼”的年资源补充量为16.7万尾,平均资源重量为7.28万公斤。目前该故道渔业所存在的主要问题是过度捕捞。为了发挥种质资源库的预期效应,建议将“四大家鱼”的开捕年龄定为3龄,严禁捕捞其当年幼鱼,捕捞强度控制在0.3～0.5间,以期故道鲢、鳙、草鱼、青鱼的持续产量保持在30万公斤左右。
This article reports the growth, mortality and resource changes of silver carp, bighead carp, grass carp and black carp in the “Four Main Fish” natural germplasm pools in the Yangtze River. The comparative analysis of the growth parameters of these four species of fish showed that the silver carp, bighead carp, grass carp and herring maintained the excellent growth characteristics of natural Yangtze River population. In 1991, the catch of the old course was 718,000 kg, of which the output of the “four major domestic fish” was 88,000 kg. The mortality rates of silver carp, bighead carp, grass carp and black carp were 0.66, 0.77, 0.86, 0.86 respectively. “Four major domestic fish,” the amount of annual replacement of 167,000, the average resource weight of 72,800 kg. At present, the main problem existing in the old fishery is over-fishing. In order to give play to the expected effect of germplasm resources pool, it is suggested that the age of catching-up of “four major domestic fish” be set at 3 years old, the fishing of the juvenile fish in that year is forbidden, the fishing intensity should be controlled between 0.3 and 0.5, The continuous production of herring remains at 300,000 kg.