|Early Stage Resource Status of Fish Species Spawning Drifting Eggs in the Jiangjin Section of the Upper Yangtze River and Their Hydrologic Requirements
|中文关键词:产漂流性卵鱼类 产卵场 水文条件 长江上游
|英文关键词:fish with drifting eggs spawning grounds early stage fish resources hydrology upper Yangtze River
| In this study, we investigated the status of fish species that spawn drifting eggs in the Jiangjin section of the upper Yangtze River, focusing on species composition, temporal dynamics of egg density, spawning grounds and their relationship with hydrologic and environmental factors. Our aim was to accumulate basic data to support the fishery resource conservation and management in the upper Yangtze River and study the ecological effects of hydraulic projects on the natural spawning of species that produce drifting eggs. The study was based on early stage fish monitoring conducted in the Jiangjin section during the spawning periods from 2019 to 2022. Hydrologic and environmental parameters were measured simultaneously, including water velocity, discharge flow, water level, water temperature and transparency. A total of 67 fish species from 13 families and 7 orders were collected during the investigation, identified using morphological and molecular techniques. 26 of the species collected produce drifting eggs and 11 were endemic to the upper Yangtze River. Recruitment of drifting eggs in the Jiangjin section were estimated at 9.32×108 in 2019, 5.82×108 in 2020, 12.24×108 in 2021 and 14.99×108 in 2022. Egg production for Rhinogobio typus, Rhinogobio cylindricus, Coreius heterodon and Ctenopharyngodon idellus was much higher than for other species. The spawning of Rhinogobio ventralis peaked in April, while spawning of Rhinogobio cylindricus and Coreius heterodon occurred from mid-May to early July. The four major Chinese carps also spawned from mid-June to early July and, for Rhinogobio typus, it was from late April to late June. Five spawning grounds for fish species producing pelagic eggs were located 170 km above the Jiangjin transect, located near Mituo, Zhuyangxi, Shimen, Jingangtuo and Youxi. There was a significant positive correlation between average daily density of eggs and discharge flow and significant negative correlation with transparency. A classification regression tree was constructed and indicated that water level, initial discharge flow and minimum transparency during discharge flooding were the critical factors affecting spawning quantity. The spawning requirements for accumulated temperature and flow varied by species. In conclusion, there were spawning grounds for many species that produce drifting eggs in the upper reaches of Yangtze River, and the location and productivity of the original spawning grounds have changed due to construction and operation of the cascaded reservoirs. We recommend ecological reservoir operation to meet the hydrological requirements for fish spawning and early life stages of pelagic species, considering the effect of hydrology and accumulated temperature on fish gonad development and the relationship between hydrological conditions and spawning ground formation.
|朱 俊,曹 俊,周 涛,杨 志,朱正强,朱其广.2024.长江上游江津段产漂流性卵鱼类早期资源现状及繁殖需求研究[J].水生态学杂志,45(1):75-86.
|查看全文 查看/发表评论 下载PDF阅读器 HTML