怒江西藏段鱼类群落结构及多样性研究

Fish Community Structure and Diversity in the Xizang Section of Nujiang River

为了探究怒江西藏段干流及主要支流鱼类群落结构及其多样性,2017-2020年在该区域设置9个调查站点,进行8次鱼类资源调查。结果表明,调查共采集到鱼类2目6科9属23种,其中怒江特有种6种,外来鱼类5种,种类数总体上呈现随着海拔上升而逐渐减少的分布趋势;优势种为怒江裂腹鱼(Schizothorax nukiangensiss)、裸腹叶须鱼(Ptychobarbus kaznakovi)和热裸裂尻鱼(Schizopygopsis thermalis),三者占调查鱼类总生物量的96.28%,占调查鱼类总数的91.25%。群落Shannon多样性指数、Simpson优势度指数、Margalef丰富度指数、Pielou均匀度指数分别为0.369~0.908、0.222~0.496、0.317~0.754、0.405~0.692,整体上处于较低水平。按生态类型可分为底栖缓流型、底栖间隙型、急流吸附型及静水中层型4类,摄食类型基本为杂食性。下游察瓦龙乡与那曲大坝上游的鱼类物种组成相似性指数最低(11.76%),支流左贡玉曲河与比如大坝下游的相似性指数最高(70.00%)。流域总体上处于中度干扰状态,上游大坝之间的河段及支流玉曲河处于较为严重的干扰状态。为了保护怒江西藏段鱼类多样性,建议在玉曲河支流设立保护区,加强流域渔政管理,规范放生行为,做好流域开发的生态保护修复与预案研究。

In this study,we explored fish community structure and diversity in the Xizang section of Nujiang River based on eight fish surveys conducted from 2017 to 2020.Our aim was to evaluate the current condition of the fishery resource,provide scientific data to support fishery resource conservation and explore the factors influencing fish community diversity.The investigation was carried out at nine survey stations,from upstream to downstream,in the Xizang section Yuqu River,the primary tributary of Nujiang River.Sampling site and time of each collected specimen were recorded,along with biological measurements,and the species.A total of 23 fish species were collected,belonging to 9 genera,6 families and 2 orders,and including 6 species endemic to Nujiang River and 5 exotic species.In general,the number of fish species decreased as altitude increased.The dominant species in the study area were Schizothorax lantsangensiss,Ptychobarbus kaznakovi and Schizopygopsis thermalis,accounting for 96.28%of the total biomass and 91.25%of the total fish number.The Shannon diversity,Simpson dominance,Margalef richness and Pielou evenness indices ranged from 0.369-0.908,0.222-0.496,0.317-0.754 and 0.405-0.692,respectively,and fish diversity was low in the Xizang section of Nujiang River.Among species,there were four ecological types:benthic slow-flow,benthic interstitial,rapid-flow adsorbed,and hydrostatic middle-layer.The feeding type was generally omnivorous.The lowest similarity index of fish species was between the Chawalong Town section of the lower Nujiang River and the upper reaches of Naqu Dam(11.76%),and the highest was between the Zuokong section of Yuqu River and the lower reaches of Biru Dam(70.00%).Overall,the fish community in the study area was moderately disturbed,and the river sections between dams in the upper reach and the Yuqu River were highly disturbed.To protect fish diversity in the Xizang Section of Nujiang River and reduce the disturbance intensity,we recommend establishing a protection area for Yuqu River tributaries,strengthening fishery management throughout the watershed,standardizing fish release,and protecting and restoring the watershed.