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,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。耗氧主要是由于水中的生物呼 Frozen northern time longer, especially in the northeast, northwest and other regions, the longest ice-pack up to 150 days or more, the water temperature under ice is low, the safety of fish overwintering a great impact on the safety of fish overwintering the most important External causes is the amount of 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 due to the biological call in the water