Fishery Resources, Environment, and Conservation in the Mississippi and Yangtze (Changjiang) River Basins

<em>Abstract</em>.—Bighead Carp <em>Hypophthalmichthys nobilis </em>and Silver Carp <em>H. molitrix </em>are native in the Yangtze River and extremely important economically and culturally as food fishes; however, the two species have declined due to overfishing and anthropogenic modifications to hydrology and water quality. Bighead Carp and Silver Carp were imported to North America in the early 1970s, escaped confinement, and have now become undesirable and problematic invasive species. The two carps have become the most abundant fish species in many portions of their invaded range, which continues to expand. We compare the biology, status, and management of these species between their natal range in the Yangtze River and their invaded habitats of the Mississippi River basin.

1997 ◽  
Vol 54 (1) ◽  
pp. 47-58 ◽  
Author(s):  
G Lu ◽  
S Li ◽  
L Bernatchez

Silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon piceus), bighead carp (Aristichthys nobilis), and black carp(Mylopharyngodon piceus) rank first, second, fourth, and seventh in world fish production. In China, the Yangtze River harbours the most important natural populations of these species. We performed a polymerase chain reaction - restriction fragment length poymorphism analysis on 365 juvenile fish representing three nursery grounds to provide a first assessment of the mitochondrial DNA diversity in these species and test the hypothesis that they are composed of more than one genetic stock. The mitochondrial DNA diversity was high in silver, bighead, and black carp, and much less in grass carp. Analysis of heterogeneity of genotype frequency, fixation indices, intersite molecular variance, and localization indices indicated that juvenile silver, bighead, and black carp from different nursery areas belong to genetically distinct populations. These results suggest that their population structure may be determined by the number of environmental settings that permit closure of their life cycle. They also imply that carp from the Yangtze River cannot be managed as a single unit and that human disturbance through exploitation and habitat modifications, in particular the construction of the Three Gorges Dam, will have differential impacts on fish abundance for different parts of the river.


2012 ◽  
Vol 66 (5) ◽  
pp. 1103-1109 ◽  
Author(s):  
Zenghu Qin ◽  
Mingwei Tong ◽  
Lin Kun

Due to the surface water in the upper reaches of Yangtze River in China containing large amounts of silt and algae, high content of microorganisms and suspended solids, the water in Yangtze River cannot be used for cooling a heat pump directly. In this paper, the possibility of using Yangtze River, which goes through Chongqing, a city in southwest China, as a heat source–sink was investigated. Water temperature and quality of the Yangtze River in the Chongqing area were analyzed and the performance of water source heat pump units in different sediment concentrations, turbidity and algae material conditions were tested experimentally, and the water quality standards, in particular surface water conditions, in the Yangtze River region that adapt to energy-efficient heat pumps were also proposed. The experimental results show that the coefficient of performance heat pump falls by 3.73% to the greatest extent, and the fouling resistance of cooling water in the heat exchanger increases up to 25.6% in different water conditions. When the sediment concentration and the turbidity in the river water are no more than 100 g/m3 and 50 NTU respectively, the performance of the heat pump is better, which can be used as a suitable river water quality standard for river water source heat pumps.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3641 ◽  
Author(s):  
Daniel K. Gibson-Reinemer ◽  
Levi E. Solomon ◽  
Richard M. Pendleton ◽  
John H. Chick ◽  
Andrew F. Casper

In the Mississippi River Basin of North America, invasive bigheaded carp (silver carpHypophthalmichthys molitrixand bighead carpH. nobilis, also referred to as Asian carp) have spread rapidly over the past several decades. In the Illinois River, an important tributary of the Upper Mississippi River, reproduction appears to be sporadic and frequently unsuccessful, yet bigheaded carp densities in this river are among the highest recorded on the continent. Understanding the causative factors behind erratic recruitment in this commercially-harvested invasive species is important for both limiting their spread and managing their harvest. We analyzed weekly catch records from 15 years of a standardized monitoring program to document the emergence of age-0 bigheaded carp in relation to environmental conditions. The appearance of age-0 fish was generally linked to hydrographic attributes, which probably serve as a cue for spawning. However, we found profound differences in the number of age-0 fish among years, which varied by as much as five orders of magnitude in successive years. The strong link between summer flooding and age-0 fish production we observed emphasizes the importance of understanding the hydrologic context in which sustained invasions occur. Despite evidence of sporadic recruitment, bigheaded carp populations in the Illinois River appear to be consistent or increasing because of particularly strong, episodic year classes.


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