Studies On The Biology And Fishery Management Of Macrobrachium Nipponense Of Dongping Lake

Dongping Lake freshwater shrimp germplasm pure, annual production of 300t, has become the mainstay of production for the lake's fisheries. Because of the biology of Macrobrachium nipponensis do not know the law, especially in the complex ecosystem of the lake's ecology M. nipponensis small lake freshwater shrimp aquaculture with a great blind, low prevalence of recapture and so on.Meanwhile, with the fishing has intensified, the amount of resources M. nipponensi dwindling. Natural increase is an effective and inexpensive means to find effective ways to restore and their proliferation is necessary. The paper on the population of M. nipponensi Dongping growth, reproduction and lake water by large breeding technology research to the Lake of the growth of M. nipponensi farming and fishing to provide a reasonable basis for information to reach the resources of M. nipponensi Dongping sustainable use purposes.This study was collected in the Dongping Lake fisheries and ecological studies of the literature data, Dongping Lake M. nipponensi resources to carry out investigations, sample collection, indoor statistical analysis, resource recovery M. nipponensi Dongping specific strategies.And the results were as the follows:1. M. nipponensis was a kind of freshwater shrimp which could be only surviving for 14 months. The body length and weight were among 1.3-6.5 cm and 0.07-6.52 g. There were two kinds of the freshwater shrimp populations.80% of the shrimps belonged to the summer population surviving from July to October of the next year, with the others belonging to the autumn population from September to December of the next year. In different stage, the respective equations of the body weight and body length of M. nipponensis in Dongping Lake are: 3-7 M W(?)=0.0162L3.2384, W♀=0.0197L3.1492 8-11 M W(?)=0.0236L2.7361,W♀=0.0151L2.32782. Growth of M. nipponensis during different population growth periodsThe growth period is divided into two evident staged with significantly difference between the growth. For the former stage, the growth is fit to Bettalanffy's equation and the growth rate decreased with the decrease of water temperature until November. For the latter stage, the growth is fit to Logistic curve and the growth rate increased with the increase of water temperature until reproduction period.3. The spawning period of M. nipponensis in Dongping Lake is from mid-April to mid-September. The egg-carrying females at the peak of spawning during mid-June are the bigger shrimps born last year with the shrimps born this year predominating gradually among the egg-carrying ones at the peak during mid-August.4. The management of freshwater shrimp resource recoveryThe spawning ground of M. nipponensis was situated in the littoral zone of the whole lake. Therefore, the protection areas should be set to protect the spawning shrimps and the depth of water should be stabilized from June to August. In order to protect parent shrimps and catch the overwinter shrimps after spawning, the closed fishing season should be set during April and June. And the strength of fishing and the number of the predators should be controlled during autumn to protect the freshwater shrimp populations.