细鳞鱼的生物学特性及其在华北分布范围的变化

BIOLOGICAL FEATURE AND DISTRIBUTIVE CHANGE OF FINE SCAL FISH IN NORTH CHINA

本文报导了细鳞鱼(Braochymystax lenokP.)的形态构造、食性及其生态环境。调查了华北地区细鳞鱼分布变化情况,并阐明由于生态环境等因素的变化是引起该种在华北地区分布范围缩小的原因,同时提出保护细鳞鱼资资源的措施。

Fine scale fish (Brachymystax lenok) is the famous and the only inland coldwater fish of Salmonidae in North China.There are small cyloid and 135-152 scales lateral line. D.Ⅲ-Ⅳ, 9-12; P.Ⅱ,16; V.Ⅱ,9; A.Ⅲ-Ⅳ, 9-11. The gill rakes 19-21, pyloric caeca 65-85. The vertebrae 57-58. The mature eggs are orange in color like a ball, the multiecithal is between 3.15-4.0mm in diameter, 33-38mg in weight. The most suitable temperature is 0-12℃, with the limitation of 15℃.The fish was widely distributed in all river in the north of the Luan river valley, and it was also distributed in the upstream of the Chaobei river system, that followed the glacier from its distributive centre- Siberia intrusion into the southern part ant cleared up in glacial period. They basically belonged to the point-like and continuous distribution in North China. Now a days since the lining environment was destroyed, this fish from continuous distributive condition changed to a small and narrow isolational point-like distribution.