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北方地区冰封期时间比较长,特别是东北、西北等地区,冰封期最长的可达150天以上,冰下水温低(约为1℃—3℃),对鱼类的安全越冬影响很大。影响鱼类安全越冬的最主要外因就是越冬池塘的溶氧量。越冬池塘封冰后,水中溶氧在自然状况下,同时存在耗氧和产氧两个方面的因素。耗氧主要是
In the northern region, the ice-seal period takes a long time, especially in the northeast and northwest regions. The longest ice-seal period can reach 150 days or more, and the water temperature under ice is low (about 1 ℃ -3 ℃), affecting the overwintering of fish Great. The main external factor affecting the safety of fish overwintering is the dissolved oxygen in winter ponds. After the wintering pond ice seal, dissolved oxygen in water under natural conditions, there are both oxygen and oxygen production factors. Oxygen consumption is mainly