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山东省地处北温带,气候温暖,年平均气温13.4℃,7月份最高气温可达26～29℃,年降雨量550～750毫米,全年光照,2,390～2,800小时,具有发展淡水渔业的优越条件。但每年的12月下旬至次年2月中旬为结冰期,鱼种越冬有很多困难,有的单位越冬鱼种成活率只有20～30%左右。1979年全省各水库开展网箱养成鱼后,大规格鱼种都是从各处坑塘、小水库收集来的。由于缺乏锻炼和长
Shandong Province is located in the northern temperate zone with a warm climate with an annual average temperature of 13.4 ℃. The highest temperature in July is 26-29 ℃ with an annual rainfall of 550-750 mm. The year-round light is 2,390-2,800 hours, which is advantageous for the development of freshwater fisheries condition. However, from the end of December to the middle of February the following year are the icing season. There are many difficulties in the winter breeding of fish species. In some units, the survival rate of overwintering species is only about 20-30%. In 1979, after all the reservoirs in the province carried out fish breeding in cages, large-sized fish species were collected from pit ponds and small reservoirs. Due to lack of exercise and long