黑龙江中游与乌苏里江大麻哈鱼(Oncorhynchusketa Walbaum)生殖群体的比较

Population structures of chum salmon (Oncorhynchus keta Walbaum)in Heilongjiang waters

1999～ 2 0 0 0年对乌苏里江和黑龙江中游大麻哈鱼 (Oncorhynchus keta Walbaum )生殖群体进行了调查 ,分析了其形态特征、生物学特性及群体结构。采用形态学和生态学方法对乌苏里江和黑龙江大麻哈鱼生殖群体进行了种群鉴别。结果表明 ,乌苏里江大麻哈鱼较黑龙江大麻哈鱼吻短、眼大、鳞大、尾柄粗短、背鳍位置稍偏前 ,且背鳍条和臀鳍条均少。各龄鱼的体长生长速度明显快于洄游至黑龙江的大麻哈鱼 ,但肥满度较低 ,性成熟早 ,繁殖力低。产卵群体个体小并以 4龄鱼占优势 ,其各龄组体长、体重均高于黑龙江群体的同龄组鱼 ;而上溯至黑龙江的大麻哈鱼产卵群体的个体大 ,以 5龄鱼为主 ,其肥满度、成熟系数及怀卵量则均高于乌苏里江产卵群体。比较乌苏里江和黑龙江大麻哈鱼群体的生物特征和群体组成 ,其差异显著 ,二者应为两个不同的地理种群或生态群体。

A survey on the population structure of chum salmon (Oncorhynchus keta Walbaum)in the waters of Heilongjiang river was conducted in 1999～2000,as a part of the program for enhance the fish which planned by Sino-Russian fishery combined committee.The average weight of up river migrating females was 3.07±0 89 kg ranging from 2.10 kg to 3.50 kg,males was was 2.59±0.90 kg ranging from 1.60 kg to 3.00 kg.The fish was quit smaller during the ending migration than the earlier population.There was some morphological difference between the populations from wusulijiang river and Heilongjiang river.The population of Wusulijiang river had a short nose ,smaller eyes,short and thick tail wrist,dorsal and anal fin had less rays which were more closed to nose than that of Heilongjiang river.Also the population in the Wusulijiang river which formed mainly by 4 years old fish had larger body,but the population of Heilongjiang river which was formed mainly by 5 years old fish was more fatty.These results showed that the chum salmon of Wusulijiang river and Heilongjiang river belongs to two different ecological population.