Population Growth of Freshwater Shrimp (Macrobrachium nipponensis) in Honghu Lake

1994年5月至1995年6月对洪湖日本沼虾种群的生长进行了研究.日本沼虾群体的平均体长、平均体重在3-6月逐渐增大,之后逐渐降低,分别在8月、9月达到最小值,其后又逐渐增大,反映出世代交替的过程日本沼虾群体的生长存在明显的阶段性,第一阶段(当年8-11月)的生长可以用Logistic生长模式来描述:(♂)Lt=6.851(1+eo.0.3186-0.2386t,Wt=(7.50/(1+e2.3845-0.3250t）·(♀)Lt6.25/(1+0.2372-0.1982tWt5.79/(1+e2.1951-0.2371t）第二阶段(翌年3-6月)的生长可以用Von Bertalanffy生长模式描述:(♂)Lt=5.40[1-1.0600(t-7.3458] W=3.43[1-e-1.0600(t-7.3458]3.2127;(♀)Lt4.76[1-e-0.5635t-5.6903],Wt=2.43[1-e-0.5635t-5.6903]3.1880日本沼虾群体的肥满度在不同生长阶段存在明显差别,不同群体之间的肥满度也存在差异.;The population growth of freshwater shrimp ( Macrobrachium nipponensis) was studied in Honghu Lake from May 1994 to June 1995. From March to June, the population is composed of shrimps born last year, and mean body length and weight increase monthly. From August to November, the population consists of ones born this year, mean body length and weight are the lowest in August and September respectivelly, afaterwards increase gradually till November. These show the course of alternation of generations.The growth period is devided into two evident stages. For the former stage (from August to November), the growth of males and females are both fit to Logistic curve and the equations are respectivelly：(♂)Lt =6.85/(1+ e0.318-0 2386t)Wt =7.50/(1+ e2 3854-0 3250t)(♀)Lt=6.25/(1 + e0 23720-0.1982t), Wt =5.79/(1 + e2l95l-0.2371t).For the latter stage (from March to June), the growth fit in von Bertalanffy's equation respectively：(♂)Lt=5.40[l-e-1 0600(t-7.3458)], Wt=3.43[1 -e-1 0600(t-7.3458) ]3.2127(♀)Lt= 4. 76[1 -e-1.5635(t-5.6903)], Wt=2.43[l-e-05635(t-5.690,3) ]31880,This report also deals with the method on studying the population growth of M. nipponen-sis t how to utilize rationally and protect effectivelly the resources of M. nipponensis.