Genetic Diversity And Resources Of The Four Major Chinese Carps In The Fuzhou Reaches Of The Fu River

Fu River of the Poyang Lake water system, one of the five rivers, is the second largest river in Jiangxi Province. Its geographic coordinates of longitude 115°30'to 117°10', north latitude 26°30'to 28°37'. To further study the fish resources in Fu River, especially the fish resources of the four major Chinese carps, we had carried out the research from 2007 to 2010 and the main results were as followed:1. April～August,2009, in Fuzhou City, the Fuzhou reaches of the Fu River, we conducted a survey on fish resources.49 species of fish were recorded, belonging to 4 orders,9 families and 36 geniuses. Among them, the most species are cyprinids, a total of 29 species, accounting for 59.18%.2. In the composition of the catch, the most was Gobioninae whose bodily form was small and Xenocyprinae which was fast growth and early sexual maturity. Some of the economic fishes that were large of individuals, late sexual maturity, long age group significantly decreased, such as black carp, grass carp, silver carp, and bighead carp and so on. The fishes which usually eated bentonic organism were the local major economic fish, such as cyprinoid, crucian, XenocyprisargenteaGunther, Pseudobagrus fulvidraco, Hemibarbus maculatus, Longnose gudgeon and loach, etc.3. April～August,2009,478 fish samples of the four major Chinese carps were collected. We could not get any carps which were breeding. In the four major Chinese carps breeding season from April to June we collected 414 samples, and we collected 64 fish fry from July to August. In the middle reaches of Fu River, the four major Chinese carps were much fewer than the main species. And most of the four major Chinese carps were age 1 or 2, accounted for more than the 99% of the total number of all the samples. In addition to the individuals of black carp and grass carp were large, the silver carp and bighead carp were smaller individuals. The overall of the four major Chinese carps in the middle reaches of Fu River showed that the individuals were small and the age structure was simple.4. The use of ISSR genetic markers on the genetic diversity of the four major Chinese carps in the Fuzhou reaches of the Fu River, we get the degree of genetic diversity index, such as the proportion of polymorphic loci P, Nei's genetic diversity H, Shannon's information index I and the genetic similarity and distance. The proportion of polymorphic loci P of the black carp was 89.29%. Its Nei's genetic diversity H was 0.2967, and Shannon's information index I was 0.4536. Its genetic similarity and distance were 0.5670 and 0.6019. The proportion of polymorphic loci P of the grass carp was 75.00%. Its Nei's genetic diversity H was 0.2201, and Shannon's information index I was0.3369. Its genetic similarity and distance were 0.7723 and 0.2644. The proportion of polymorphic loci P of the silver carp was 76.19%. Its Nei's genetic diversity H was 0.1860, and Shannon's information index I was 0.2992. Its genetic similarity and distance were 0.7600 and 0.2869. The proportion of polymorphic loci P of the bighead carp was 67.50%. Its Nei's genetic diversity H was 0.2365, and Shannon's information index I was 0.3531. Its genetic similarity and distance were 0.7938 and 0.2351. The result of our study indicated that the four major Chinese carps in the Fuzhou reaches of Fu River had abundant genetic diversity.5. After the dam of Liaofang using to intercept flood and retain water, the environment of the middle reaches of the Fu River had undergone heavily changes, and the fish resources of the middle reaches of the Fu River had been great impact. Mainly behaviors were that the reservoir area of sediment deposition, water level risen, aquatic breeding. The water level under the dam had dropped below, the water volume hierarchy disturbance, sediment reduction. Up and down of the dam, the ranges of the water level changes were little, and the fish migration channels had disappeared. Because of the above reasons, in the reservoir area, the fishes which were feed on herbivorous and plankton had largely propagated. The major fishes of the river under the dam were usually feed on the bentonic organism. Because of the dam, the river was separated. And the swimming fishes and the semi-swimming fishes could not get back to the spawning site and proceed to reproduce.