雅鲁藏布江中游仔稚鱼种类组成与分布特征

Composition of species and distribution of fish larvae and juveniles in the middle reach of Yarlung Zangbo River

于2015年4月、2015年6月和2016年4月实地调查了雅鲁藏布江中游仔稚鱼的种类组成、空间分布和栖息环境特征。实地调查共设置24个采样点,采用手抄网在鱼群密集水域采集仔稚鱼样本,并通过Cyt b基因序列比对对样本种类进行判定。共采集到仔稚鱼样本3502尾。Cyt b基因序列比对显示,采集到的仔稚鱼共属于2科5属10种,其中,土著种分别为细尾高原鳅(Triplophysa stenura)、异尾高原鳅(T.stewarti)、拉萨裸裂尻鱼(Schizopygopsis younghusbandi)、尖裸鲤(Oxygymnocypris stewartii)、巨须裂腹鱼(Schizothorax macropogon)、异齿裂腹鱼(S.oconnori)、拉萨裂腹鱼(S.waltoni)、双须叶须鱼(Ptychobarbus dipogon),另发现未记录于本水域的怒江高原鳅(T.nujiangensa)、裸腹叶须鱼(P.kaznakovi)。以上两种仔稚鱼出现原因尚未阐明。裂腹鱼类仔稚鱼的种类分布存在较大空间差异,高原鳅类仔稚鱼的种类数的空间分布则较为均匀。本研究表明,雅鲁藏布江中游大部分江段均比较适宜鱼类的繁衍栖息,但需重点保护裂腹鱼类的关键育幼场所。

A field survey in the middle reach of Yarlung Zangbo River was conducted to comprehend the composition of species,distribution and characteristics of the habitat of fish larvae and juveniles in April 2015,June 2015 and April 2016.A total of 24 sampling sites were set.For each site,a dipnet was used to catch the fish larvae and juvenile samples,and then the sample was identified using mitochondrial DNA Cyt b gene sequences alignment.A total of 3502 fish larvae and juveniles were sampled.Gene sequences identification showed that the samples belonging to the ten species,two families and five genus,including endemic species Triplophysa stewartia,T.nujiangensa,Schizopygopsis younghusbandi,Oxygymnocypris stewartia,Schizothorax macropogon,S.oconnori,S.waltoni,and Ptychobarbus dipogon,and exotic species T.stenura,P.kaznakovi.The sources of the two exotic fish species were unknown.The distribution of larvae and juveniles in the sub-family Schizothoracinae exhibits significant spatial variations,while those in the family Balitorida were distributed uniformly.This study indicated that most sections of the middle reaches of the Yarlung Zangbo River were suitable for fish reproduction and habitat.Still,it is necessary to focus on protecting the critical breeding and nursery sites of fishes in the sub-family Schizothoracinae.