Long-term changes in fish community and the impact of exotic fish, between the Nakdong River and Upo Wetlands

2011 ◽  
Vol 34 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Hyun-Bin Jo ◽  
Min-Ho Jang ◽  
Kwang-Seuk Jeong ◽  
Yun-O Do ◽  
Gea-Jae Joo ◽  
...  
Keyword(s):  
Fish Community ◽  
Nakdong River ◽  
Exotic Fish ◽  
Long Term Changes ◽  
The Nakdong River ◽  
The Impact

scholarly journals Effect of the Human Utilization of Northern Snakehead (Channa argus Cantor, 1842) on the Settlement of Exotic Fish and Cladoceran Community Structure

2021 ◽  
Vol 13 (5) ◽  
pp. 2486
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim
Keyword(s):  
Community Structure ◽  
Fish Species ◽  
Micropterus Salmoides ◽  
Lepomis Macrochirus ◽  
Nakdong River ◽  
Exotic Fish ◽  
Carnivorous Fish ◽  
Channa Argus ◽  
The Nakdong River ◽  
Exotic Fish Species

Empirical studies suggest that changes in the density of top predators, such as carnivorous fish, in freshwater food webs, strongly affect not only fish communities but also various primary and secondary consumers. Based on these findings, we explored how differences in the utilization of carnivorous fish (i.e., Northern Snakehead, Channa argus) by humans affected the fish and cladoceran community structure as well as the settlement of exotic fish species (i.e., Lepomis macrochirus and Micropterus salmoides) in 30 wetlands located in the upper and lower reaches of the Nakdong River. Our results show that in the mid–lower reaches of the Nakdong River, the density of C. argus was low, while high densities of L. macrochirus and M. salmoides were observed. Exotic fish species are frequently consumed by C. argus, leading to a low density of L. macrochirus and M. salmoides in the upper reaches, which supported a high density of C. argus. However, in the mid–lower reaches, the density of L. macrochirus was high because of the frequent collection of C. argus by fishing activities. The dominance of L. macrochirus significantly changed the structure of cladoceran communities. L. macrochirus mainly feeds on pelagic species, increasing the density of epiphytic species in the mid–lower reaches. The continued utilization of C. argus by humans induced a stable settlement of exotic fish species and strongly affected the community structures of primary consumers in the 30 wetlands. The frequency of C. argus collection has to be reduced to secure biodiversity in the mid–lower reaches of the Nakdong River, which will reduce the proportion of exotic fish species and increase the conservation of native fish.

Uncertainty Improvement in a Simulation of Channel Evolution

2012 ◽  
Vol 212-213 ◽  
pp. 341-344
Author(s):  
Kwang Ik Son ◽  
Taik Jean Hwang ◽  
Man Ha Hwang ◽  
Young Ho Yoon
Keyword(s):  
Nakdong River ◽  
Channel Evolution ◽  
Alluvial Channel ◽  
Longitudinal Slope ◽  
Bed Materials ◽  
Channel Degradation ◽  
The Nakdong River ◽  
The Stability ◽  
Natural Channel

The Four Major Rivers Restoration Project (4MRRP), one of the largest river rehabilitation projects in Korea, has being carried out during the last three years. 0.57 billion m3 of sediment was dredged to widen and deepen the channel along four major rivers, the Han, Nakdong, Geum, and Youngsan rivers. As a result of reshaping the natural channel to a trapezoidal channel, and the construction of 16 weirs, the change of longitudinal slope of the river was inevitable. The distribution of bed materials was also changed, due to dredging. Therefore, the rivers were totally disturbed, and the stability of the rivers could not be assured. In particular, the Nakdong river, the second largest river in Korea, has the characteristics of an alluvial channel. Degradation of the main channel bed caused bank erosion, and head-cut phenomena in many tributaries. Deformations of the main channels could be observed all along the river. Long-term simulation of the channel evolution and prediction of the stability of the Nakdong river have to be examined, to cope with the instability of the river, which could lead to unexpected river disasters. This study deals with the methodology of uncertainty improvement, in analysis of the simulation and confirmation with field survey data. Methodology of uncertainty improvement in description of weir, whose discharge coefficient is unknown, in a river was suggested.

Longitudinal patterns in limnological characteristics based on long-term ecological research in the Nakdong River

2011 ◽  
Vol 34 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Dong-Kyun Kim ◽  
Dong-Gyun Hong ◽  
Hyun-Woo Kim ◽  
Gea-Jae Joo ◽  
Kwang-Seuk Jeong
Keyword(s):  
Ecological Research ◽  
Nakdong River ◽  
Longitudinal Patterns ◽  
Long Term Ecological Research ◽  
The Nakdong River

Long-Term Variations of Water Quality and Material Flux in the Nakdong River, Korea

2016 ◽  
Vol 24 (6) ◽  
pp. 161-169 ◽  
Author(s):  
Sang-Chol Yoon ◽  
Shyun-Hyun Yoon ◽  
Seung-Mok Lee ◽  
Yi-Yong Yoon
Keyword(s):  
Water Quality ◽  
Nakdong River ◽  
Material Flux ◽  
The Nakdong River ◽  
Long Term Variations

scholarly journals Analyzing the market position of fish species subject to the impact of long-term changes: a case study of French fisheries in the Bay of Biscay

2008 ◽  
Vol 21 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Pascal Le Floc'h ◽  
Jean-Charles Poulard ◽  
Olivier Thébaud ◽  
Fabian Blanchard ◽  
Julien Bihel ◽  
...  
Keyword(s):  
Fish Species ◽  
Bay Of Biscay ◽  
Market Position ◽  
Long Term Changes ◽  
The Impact
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