scholarly journals Spatiotemporal Distribution and Species Composition of Fish Assemblages in the Transitional Zone of the Three Gorges Reservoir, China

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3514
Author(s):  
Pengcheng Lin ◽  
Lin Chen ◽  
Xingchen Gao ◽  
Chunling Wang ◽  
Xin Gao ◽  
...  

The river–reservoir transitional zones play an important role in maintaining riverine fish biodiversity and abundance in highly regulated rivers. The Upper Yangtze River, which contains 286 fish species, is experiencing intense hydropower development. However, few studies have been conducted on the spatial distribution of fish in the river–reservoir transitional zones in the Upper Yangtze River, and it is therefore difficult to predict how this development will impact the region. In this study, a 200-kHz split-beam acoustic system in combination with biological samplings was used to investigate the composition and spatiotemporal distribution of the fish in the transition zone of the Three Gorges Reservoir (TGR) in 2017. The biological samplings comprised 7434 individuals from 61 species, 38 genera, 15 families, and 5 orders. The dominant fish species were Rhinogobio cylindricus, Coreius guichenoti, Hemiculter bleekeri, and Pelteobagrus vachelli. Acoustic detection identified the mean target strength (TS) to be −55.6 in May, −57.8 in August, and −55.8 dB in December. Accordingly, the average fish density was 4.96, 6.96, and 4.42 ind/1000 m3. Significant differences were found in the TS and fish density between flood season (August) and non-flood season (May and December). Spatially, fish preferred the meandering sections at 10–20 m deep. A size-dependent vertical distribution pattern was observed, with larger fish in the deeper layers and smaller fish in shallower waters. Lastly, our results suggest that meandering deep channels should be assigned high priority with respect to fish conservation in the Upper Yangtze River.

<em>Abstract</em>.—In this paper, we report fish resources in the upper reach of the Yangtze River from 2011 to 2012. The five sampling locations were Yibin, Hejiang, Mudong, Wanzhou, and Zigui. Yibin and Hejiang are the most upstream locations; Mudong is at the upper end of the Three Gorges Reservoir while Wanzhou and Zigui are in the inundated areas of the Three Gorges Reservoir. During our investigations, we collected 56, 94, 93, 67, and 64 fish species, respectively, from these five locations. Among them, 13, 21, 17, 4, and 4 are endemic to the upper Yangtze River. Catch per unit effort calculated with pooled data were 1,221.6–6,433.9 g/(d• boat). Because Yibin and Hejiang are still in the riverine state, endemic species remain. These areas are also in the national protected areas range. We suggest that commercial fishing should be banned in these areas to protect endemic fish species. However, for Wanzhou and Zigui, because they are in the inundated reservoir area, dominance has shifted from riverine to lacustrine species. Fisheries strategies should also be changed to target on different species, employ different fishing gears, and apply different management strategies.


2014 ◽  
Vol 641-642 ◽  
pp. 70-74
Author(s):  
Hua Ge ◽  
Ling Ling Zhu ◽  
Ren Yong Huang

The non-uniform sediment input has played a significant role in the bed evolution in the middle and lower Yangtze River, which indirectly influences the amount of the sediment transported into the East China Sea every year. However, it has been dramatically changed by the climate change, especially the human activities in the upper Yangtze River, not only the amount, but also the grading. The average annual sediment load has reached to 402.6 million tons since 1960s, while showing a decreasing and refining trend mostly influenced by the human activities, such as soil and water conservation, and large hydropower projects. The most direct consequence of these changes was to cause severe erosion in the middle and lower Yangtze River, further to bring about fluvial regime adjustment. In this article, a series of daily and annual averaged sediment transport data since 1960’ were collected and analyzed to find the impacts of the significant human activities on the non-sediment input of the middle Yangtze River, and then its variation tendency was predicted, affected by the existed large hydropower projects and to be build ones in the upper Yangtze river. The result shows that the non-uniform sediment input of the middle Yangtze River was slightly reduced by the operation of Gezhouba Project and the up and middle Yangtze River water and soil conservation prevention and control projects, and further less after the impoundment of Three Gorges Reservoir, meanwhile its grading has been getting finer and finer. In future, along with the normal operation of the Three Gorges Reservoir and the built of the cascade reservoirs in the upper main stream and tributaries of the Yangtze River, it will be continuously reduced and refined.


2018 ◽  
Vol 144 (8) ◽  
pp. 05018006 ◽  
Author(s):  
Wenjie Li ◽  
Shengfa Yang ◽  
Yi Xiao ◽  
Xuhui Fu ◽  
Jiang Hu ◽  
...  

2013 ◽  
Vol 864-867 ◽  
pp. 2207-2212 ◽  
Author(s):  
Jing Zheng

In the middle and downstream area of the Yangtze River, low water levels had occurred at post-flood season or before the flood season in recent years, since the trial impoundment of the Three Gorges Reservoir (TGR) in 2008. Based on the analysis of the low water levels, both rating curve of main stations in the middle and lower reaches of the Yangtze River and the operation of TGR in the dry season were analyzed in study to reveal the effects of the impoundment of TGR on water level of downstream areas. The research results show that the water supplement of the TGR could raise the downstream water level, which has positive effect on water supplement and navigation in this area.


2016 ◽  
Vol 32 (6) ◽  
pp. 1268-1272 ◽  
Author(s):  
S. B. Chen ◽  
C. S. Liao ◽  
Z. J. Li ◽  
T. L. Zhang ◽  
S. W. Ye ◽  
...  

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