金沙江下游宜宾段产漂流性卵鱼类早期资源动态变化

为探讨金沙江下游溪洛渡和向家坝水电站蓄水运行对下游江段鱼类早期资源群聚动态的影响，基于2016-2020年宜宾江段鱼类早期资源调查数据，探究其资源种群结构与年际变化趋势。使用半圆弶网采集漂流性卵，通过分子生物学方法进行种类鉴定，并计算鱼卵丰度。结果表明，宜宾江段共计采集鱼卵20种，主要优势种为吻鮈(Rhinogobio typus)和寡鳞飘鱼(Pseudolaubuca engraulis)；估算出鱼卵年均径流量为15.07×106粒，其中漂流性卵为9.89×106粒，年际间总体呈增加趋势；推算采样点以上分布有产漂流性卵鱼类产卵场3处；从多样性指数和相似度指数看，宜宾江段鱼卵种类组成结构较为稳定，年际间变化不大。尽管受金沙江下游水电工程开发的影响，宜宾江段作为长江上游珍稀特有鱼类国家级自然保护区的重要组成部分，仍是产漂流性卵鱼类产卵繁殖的重要分布区，但以小型鱼类为主，圆口铜鱼(Coreius guichenoti)、长鳍吻鮈(Rhinogobio ventralis)等长距离洄游性鱼类鱼卵没有监测到。建议继续加强圆口铜鱼、长鳍吻鮈等鱼类的增殖放流；针对产漂流性卵小型鱼类的生态需求，开展...

Dynamic changes of early fish resources in Yibin section of the lower of Jinsha River after the storage of Xiluodu and Xiangjiaba hydropower station

In order to discuss the dynamic changes of early fish resources after storage of Xiluodu and Xiangjiaba hydropower station, the population structure and temporal trends of early fish resources were studied in Yibin section of the lower Jinsha River based on the resarch from May to July in 2016-2020. The results showed that there were 20 fish species with eggs, and the dominant species were Rhinogobio typus and Pseudolaubuca engraulis. It was estimated that the total quantity of fish eggs was 15.07×10⁶ and showed an increasing trend while drifting eggs was 9.89×10⁶ from 2016 to 2020. By inferencing, there were three spawning grounds of drifting eggs of fish from the sampling section above to the area below Xiangjiaba Dam. According to the diversity index and similarity index, the composition of eggs species in Yibin section was relatively stable, with little change between years. Under the background of cascade development of Jinsha River , Yibin section was still an important distribution area for spawning and breeding of drifting eggs fish and have some complementary roles to the national nature reserve of rare and endemic fish in the upper Yangtze river, but there were mainly pelagic broadcast-spawning small fishes, while the eggs of the long distance migratory fish such as Coreius guichenoti and Rhinogobio ventralis were not collected. So, we should strengthen continuously the proliferation and release of species such as Coreius guichenoti and Rhinogobio ventralis, meanwhile, study the ecological requirements of pelagic broadcast spawning small fishes to evaluate study the ecological effect of the cascade reservoirs in Jinsha River basin.