Reproductive Characteristics And Resource Restoration Technique Of Neosalanx Taihuensis In Wuqiangxi Reservoir

We have conducted a dynamic investigation among6sampling sites in Wuqiangxi reservoir in the period of2011to2013. Our purpose is to find out the water quality grade and fish-producing capacity of the reservoir,gonad development and the relationship between fecundity and weight and length of N. taihuensis,and the factors influcing the resource of N. taihuensis and technique restoring the resource of N. taihuensis. The main results were as follows:1. The water quality were detected by chemical analysis method and its grade were evaluated by single factor index method. The results showed that the content of TN and TP were overproof. It showed that the river was in a eutrophication level and the annual water quality was bad. The average biomass was5.71mg/L. The theoretical value of silver carp and bighead carp was2951608kg and the theoretical value of N. taihuensis was2635583kg.2. By observing its ovarian tissue slice, it indicated that N. taihuensis was a multiple spawner and the breeding season of spring group is from February to April and autumn group is middle or late September. The average fecundity was1416. Analysis indicated that, there was a power function relationship between the absolute fecundity and body-length, the equation was:F=2.464967L2.439383(L=length); there was a linear relation between fecundity and body-weight, the equation was:F=-72.20548+1353.384W (W=weight).3.After setting a production target that based on the fish productivity, we evaluated the stock of N. taihuensis, finding out the reasonable amount of fishing at last. The practical resource of N. taihuensis minus the stock is the reasonable amont of fishing. Hydrologic condition and plankton biomass as well as predation and fishing intensity were important influential factors to the distribution of N. taihuensis. Reasonable fishing time is Septemper to November and fishing ban period is February to April. Through adjusting the structure of fishes, reinforcing the fhishery management, enacting fishing ban period and enhancement and releasing, the resource of N. taihuensis in Wuqiangxi Reservoir could be restored and used reasonable.