太湖麦穗鱼生长、死亡和利用状况评估

为研究太湖麦穗鱼Pseudorasbora parva的种群结构、生长特征、死亡特征和资源利用状况,于2014年1—12月使用虾笼网在太湖水域逐月进行了采样调查,并对采集的1207尾样本进行了分析。结果表明:麦穗鱼样本标准体长为27.03~107.36 mm,平均为(60.03±13.29)mm,体质量为0.4~21.2 g,平均为(4.51±3.16)g;其体长与体质量呈幂函数相关,拟合关系式为W=2.1606×10-5L2.9537(R2=0.9323,n=1207);Von Bertalanffy生长方程各参数为L∞=112.88 mm、K=0.46、t0=-0.51 a,体质量生长拐点为1.84a;应用变换体长渔获曲线法估算总死亡系数(Z)为1.87,利用Pauly经验公式估算自然死亡系数(M)为1.07,捕捞死亡系数(F)为0.80,开发率(E)为0.43。研究表明,太湖水域麦穗鱼面临的捕捞压力较轻,处于适度利用状态,这与太湖水域无针对性捕捞且设有禁渔期有关,同时开捕期内肉食性鱼类面临的捕捞压力也有利于小型鱼类种群增殖。

Growth and mortality of topmouth gudgeon Pseudorasbora parva and evaluation on resource utilization in Taihu Lake

Based on a total of 1207 samples of topmouth gudgeon Pseudorasbora parva collected by shrimp pot from January to December in 2014, an investigation was conducted monthly in Taihu Lake to study the composition, growth and mortality of capture as well as the resources utilization. The standard body length of samples ranged from 27 . 03 mm to 107 . 36 mm with mean value of ( 60 . 03 ± 13 . 29 ) mm while the body weight ranged from 0 . 4 g to 21. 2 g with the mean value of (4. 51±3. 16) g. A power function was presented between the body length and body weight while the relationship exhibited as follows:W=2. 1606í10-5L2.9537(R2=0. 9323, n=1207). The parameters of Von Bertalanffy growth equation were displayed as below:L∞=112. 88 mm, K=0. 46, t0=-0. 51 a. The inflec-tion point of body weight was about 1. 84 years. Total mortality coefficient (Z) was 1. 87 estimated by transformed body length catch curve method and natural mortality coefficient ( M) was estimated about 1. 07 with Pauly equa-tion. Fishing mortality coefficient (F) was 0. 80 and exploitation rate (E) was 0. 43. The results showed that top-mouth gudgeon confronting lower fishing pressure in Taihu Lake,stayed in a moderate utilization state which was re-lated to non-targeted fishing and the enactment of forbidden fishing period in Taihu Lake, and the meanwhile, fish-ing pressure that carnivorous fishes faced in fishing period was beneficial to the proliferation of small-sized fish spe-cies as well.