我省地域辽阔,从东到西气候差异很大,鱼池结冰和解冰的时间也不尽相同,一般十一月初到十一月底结冰,第二年三、四月份冰面融化,越冬鱼类在冰下生活长达五、六个月。每年越冬后期,特别是解冰后,发生大批死鱼的池塘不乏其例,给生产者往往造成重大的经济损失。据不完全统计,仅兰州地区越冬鱼死亡率超过30％的池塘,占越冬池总数的3％～4％,由此 The vast territory of our province, from east to west climate is very different, the pond ice and ice time are not the same, usually in early November to the end of November frozen, the next year in April and April melting ice, wintering fish Classes live under ice for up to five or six months. After the winter overwintering period, especially after the ice is lifted, there are many cases of dead fish ponds, which often cause significant economic losses to the producers. According to incomplete statistics, only the ponds with more than 30% mortality of overwintering fish in Lanzhou account for 3% ~ 4% of the total number of wintering ponds, thus