利用捕捞数据估算长江中华鲟资源量的新方法

 对一定水域内鱼类种群数量(资源量)的估算,是鱼类资源管理和保护的基础.中华鲟资源量及其变动的研究一直是一个广泛关注、悬而未决的难题,从而影响了对中华鲟的有效保护.本文根据中华鲟繁殖群体存在两个股群的特点,首次建立了利用捕捞数据估算其资源量的理论和方法,对葛洲坝截流后的中华鲟资源量进行了初步估算.结果表明,由于葛洲坝的阻隔作用和过度捕捞的影响,中华鲟年际资源增长率从1981年的6.92,到1984年以后相对稳定在0.793~0.956之间,1984年中华鲟资源量达到最大,以后中华鲟资源量逐年减少.1981—1990年中华鲟多年平均资源量为1348尾,年均资源补充量767尾.本文还对中华鲟资源量估算理论和方法及捕捞对其影响进行了分析和讨论,结果表明,(1) 本文的估算理论和方法是可行的,估算精度可靠.(2) 初始值变化对估算结果的影响逐年衰减.(3) 捕捞对中华鲟的年际增长率和未成熟个体比例系数均有显著影响.

A New Method of Estimation on Populations of Chinese Sturgeon in the Yangtze River by Using Existing Fishing Data

The estimation of fish populations in certain waters is the basis of fishery resources management and conservation. The populations of Chinese sturgeon (Acipenser sinensis Gray) in the Yangtze River and its variation have received public attention and become a pending tough issue. Firstly, according to the features of reproduction population, the theory and method for estimating the populations of Chinese sturgeon in the Yangtze River from the year of 1981 to 1990 are established by using existing fishing data. It is indicated that between 1981 and 1990 there are 1,348 individuals on average with annual stock recruitment of 767 individuals in the Yangtze River. In addition, the estimation of Chinese sturgeon population and effects of fishing data are discussed, it is concluded that, (1) the theory and method for population estimation are feasible and of credibly accurate; (2) sensitivity analysis on the population estimation has been conducted; and (3) the level of resources utilization(fishing) has an obvious impact on both annual growth rate and immature individual scale factor for Chinese sturgeon.