在上海与广东两地的池塘中,对4种不同繁育群体鲢、鳙,即长江天然繁殖鲢、鳙,长江流域人工繁殖鲢、鳙,珠江天然繁殖鲢、鳙,以及珠江流域人工繁殖鲢、鳙,从二龄(1~+)起至四龄,逐年观察不同群体在各龄期的性腺发育状况及催产结果,发现在广东培育的比在上海培育的早一年成熟,这与天然环境里珠江鲢、鳙比长江鲢、鳙早成熟一年一致;而在同一饲养环境里,长江天然繁殖鲢、鳙与珠江天然繁殖鲢、鳙同时成熟,长江人工繁殖鲢、鳙与珠江人工繁殖鲢、鳙同时成熟,表明环境因子在不同繁育群体的性腺发育速度上起决定作用。人工繁殖鲢、鳙同天然繁殖鲢、鳙同时成熟则表明在无近交情况下,人工繁殖不会导致早熟。据推算,鲢发育成熟约需20000度日的总热量,鳙发育成熟约需26000度日的总热量。 In the ponds between Shanghai and Guangdong, the results showed that there were no significant differences in the growth rates of silver carp, bighead carp, bighead carp and bighead carp in the four different breeding groups, the natural breeding silver carp in the Yangtze River, the artificial breeding silver carp in the Yangtze River valley,鳙, from the second age (1 ~ +) until the age of four, year after year to observe the different groups of gonadal development at various ages and the results of oxytocin, found in Guangdong cultivate more than in Shanghai cultivated a year earlier, and the natural environment In the same rearing environment, the natural breeding of silver carp in the Yangtze River and the natural breeding of silver carp and Pearl River in the Pearl River at the same time mature, the Yangtze River artificial breeding of silver carp and bighead carp and the Pearl River artificial breeding of silver carp , Simultaneously mature, indicating that environmental factors play a decisive role in the gonadal development speed of different breeding populations. Artificial breeding of silver carp, silver carp with natural reproduction, 鳙 Simultaneous maturity shows that in the absence of inbreeding, artificial reproduction does not lead to premature. It is estimated that the development of silver carp mature about 20000 degrees of total calories, 鳙 mature maturity about 26,000 degrees of total calories.