三峡水库秀丽白虾生长与繁殖生物学特征研究

2012 年11 月至2013 年10 月逐月对三峡水库木洞江段秀丽白虾的生长和繁殖生物学特征进行了研究。结果显示秀丽白虾是一年生的虾类, 寿命为1214 个月。雌性个体的平均体长(37.727.92) mm 显著大于雄性(37.086.59) mm, 具有明显的雌雄异形现象。秀丽白虾的渐近体长(L)为59.33 mm, 生长系数(K)是1.6/年, 生长方程为:Lt=59.33-e-1.6(t+0.081)。雌虾繁殖季节从4 月上旬持续至9 月下旬, 繁殖高峰期为4 月中旬至6 月中旬, 由越冬虾和当年虾两个世代的繁殖群体组成。抱卵雌虾的体长为27.0753.71 mm, 平均体长(L50)为37.06 mm。雌雄性比月变化为1.112.36, 平均为1.46, 群体中雌性个体数量显著多于雄性(P 0.001)。绝对繁殖力(FA)为31294 粒, 相对繁殖力(FR)为(11522)粒/g。绝对繁殖力与体长呈幂函数关系(FA=0.0031L2.8632, r=0.72, n=106), 而与体重呈直线关系(FA=104.63W+9.9534, r=0.79, n=106)。卵径(D)平均值为(1215102) m。为合理保护和利用三峡水库秀丽白虾种群资源, 建议加强虾类捕捞管理, 繁殖期间(49 月)禁止捕捞虾类或限制捕捞强度。  

THE GROWTH AND THE REPRODUCTIVE BIOLOGY OF EXOPALAEMON MODESTUS (HELLER, 1862) (CRUSTACEA,DECAPODA, PALAEMONIDAE) IN THE THREE GORGES RESERVOIR OF CHINA

We conducted monthly study on the growth and the reproductive biology of shrimp Exopalaemon modestus in the Three Gorges Reservoir from November 2012 to October 2013. The typical life span of the shrimp was 1214 months. E. modestus showed a clear sexual dimorphism in the body length, and the females were significantly larger in size than the males. The Von Bertalanffy growth function was estimated to be Lt=59.33-e-1.6(t+0.081) based on the frequency of the body length. The ovigerous females were monitored between early April and late October, and we found that the peak reproductive period was from mid April to mid June. The spawning populations included wintering and yearling individuals. The body lengths of the ovigerous females ranged from 27.07 to 53.71 mm, and the body length of 50% was estimated to be 37.06 mm. The overall sex ratio was 1.46:1 and females significantly outnumbered males. The absolute fecundity of E. Modestus ranged from 31 to 294 eggs (12753) eggs, meanSD, and the relative fecundity was (11522) eggs/g (meanSD). The absolute fecundity was related to the body length (FA=0.0031L2.8632, r=0.72, n=106) and the body weight (FA=104.63W+9.9534, r=0.79, n=106). The average diameter of the eggs of E. Modestus was (1215102) m (meanSD, n=4171). In order to properly protect and utilize the freshwater shrimp resources, we recommended to apply more strict management policies on shrimp harvest, for example, to reduce or forbid captures during the spawning season (April to September).