韩江淡水鱼类区系

Ichthyofauna of the Hanjiang River for Freshwater Fishes

韩江为广东省第二条大河，拥有１０２种淡水鱼类，隶属于１６科，７１属．其中鲤科计５６种，鳅科计７种，平鳍鳅科计８种，即鲤形目鱼类在总体上占有最优势的地位．在鱼类区系的组成来看，韩江鱼类与榕江鱼类、九龙江鱼类十分相似．这与它们其有相似的地理状况的河道，以及冰河期间有过联系有关．这些河系的鱼类在早第三纪开始形成．由南亚与东亚地区的淡水鱼类综合而成：一些属如小条鳅属、沙鳅属、异属、白甲鱼亚属从南亚进入，但止于这些水系而决不进入闽江；而东亚广泛存在的属，如青鱼属、草鱼属、鲢鱼属、鳙鱼属、红属、鲴属、鳅属、属等在较晚时期大量拥入．至于北方起源的胭脂鱼、属向南可抵达闽江，但并不扩展到本地区．

Originating from the south slope of Wuyi Mountain,the Hanjiang River is the second largest river in Guangdong Province with a length of 470 kilometer.102 species of freshwater fishes have been found in the Hanjiang River,classifiedinto 16 families,or 71 genera.Cyprinids include 56 species (or 54.9% of the total),Cobitids 7 (or6.9%),and Homalopterids 8 (or7.8%).The freshwater fishes in Hanjiang River were compared with those of nearby rivers.Fishes of the Hanjiang River are very much similar to those of the Rongjiang River and the Jiulongjiang River in genera and species.There are similar physical geographical feathers in the three river basins,which probably joines together in the Ice age,to form a zoogeographical area.The ichthyfauna of the Hanjiang River was formed in the early Tertiary Period.Some of the freshwater fishes came from South Asia and others from the East Asia Plain.Some genera such as Micronemacheilus,Botia,Parazacco,Onychostoma migrated into this zoogeographical area from South Asia.Most genera evolved in East Asia,Suchas Ctenopharyngodon,Mylopharyngodon,Hypophthalimichthys,Aristichthys Erythroculter,Xenocypris,Gobiobotia,Acheilognathus etc entered this region from late-Tertiary.Some genera originated from the north such as Myxocyprinus,Phoxinus entered the Mingjiang River,but never reached this area.