长江上游异鳔鳅鮀种群资源现状

Status of the population resources of Xenophysogobio boulengeri in the upper reach of Yangtze River

2010年10月至2011年7月在长江上游宜宾至江津江段,采集异鳔鳅鮀(Xenophysogobio boulengeri)405尾。采用体长股分析法(LCA)对其资源量进行初步评估,运用Beverton-Holt动态综合模型对其资源变化趋势进行分析。结果显示:现阶段长江上游异鳔鳅鮀的补充年龄(tr)、开捕年龄(tc)及极限年龄(Tmax)分别为1.1a、1.5a及11.7a;种群总死亡系数(Z)、自然死亡系数(M)及捕捞死亡系数(F)分别为1.31/a、0.57/a及0.74/a。当前开发率(Ecur)为0.57,表明该种群已面临较高的捕捞压力。2010年至2011年长江上游异鳔鳅鮀的年平均资源量及资源尾数分别为0.350×104kg、0.533×106尾,初始资源量及资源尾数分别为0.627×104kg、0.957×106尾。研究表明:长江上游异鳔鳅鮀种群资源已处于过度利用状态,且渔获物以幼鱼为主。建议将长江上游异鳔鳅鮀的最小可捕规格定为94.43 mm,以保护其资源不被过度开发。

Based on the fishery resources monitoring data collected in the Yi Bin and Chong Qing section of the upper rea -ches of the Yangtze River from October 2010 to July 2011 , the stock biomass was estimated by length-based cohort analysis （ LCA） , the population dynamics was evaluated by Beverton-Holt dynamic model .The ages at recruitment , at first capture and the terminal age were 1.1a, 1.5a and 11.7a, respectively.The total mortality rate （Z）, natural mortality rate （M） and fishing mortality rate （F） of the population were 1.31/a, 0.57/a and 0.74/a, respectively.The current exploitation rate （E） was 0.57, indicating that the population had faced with overfishing .From 2010 to 2011, the average stock bio-mass and number of X.boulengeri in the upper Yangtze River were 0.350 ×104 kg and 0.533 ×106 ind., the initial stock biomass and number were 0.627 ×10 4 kg and 0.957 ×10 6 ind, respectively . It was concluded that the stock of X.boulengeri in the upper Yangtze River had been over-exploited, and the young fish were occurred in the catches with large amount .To protect the resources of X.boulengeri in the upper Yangtze River , the length at first capture should be fixed with 94.43 mm.