南渡江上游海南半鲿生物学参数估算

为研究海南半鲿(Hemibagrus hainanensis Tchang 1935)种群生物学及资源动态特征, 2019年1—12月于南渡江上游采集358尾海南半鲿,其体长范围为42—289 mm,体质量范围为1.14—282.79 g。利用FiSATⅡ软件中ELEFAN I法估算南渡江上游海南半鲿种群参数,其资源变动趋势则通过Beverton-Holt动态综合模型进行评估。结果显示:von Bertalanffy生长方程所描述的各参数值分别为L∞=304.5 mm、K=0.49、t0=–0.29,体质量的生长拐点为t=1.95,即TL=202.9 mm。利用Pauly经验公式和长度变换渔获曲线法分别估算出:自然死亡系数(M)为1.05,总死亡系数(Z)为1.22,捕捞死亡系数(F)为0.17及资源开发率(E)为0.14,表明其资源未处在过度捕捞状态。研究结果填补了南渡江上游海南半鲿的种群生长特性及动态特征基础资料的空白,为其种群资源恢复和保护策略的制定提供理论依据。

ESTIMATION OF BIOLOGICAL PARAMETERS OF HEMIBAGRUS HAINANENSIS IN THE UPPER NANDU RIVER

Hemibagrus hainanensis is a rare, endemic fish species in inland waters of Hainan. There is very little information about its basic biology in this region. A total of 358 fish samples were caught from the upper Nandu River from January to December 2019. The body length of H. hainanensis ranged from 42 to 289 mm, and weighed between 1.14 and 282.79 g. Moreover, the population parameters of H. hainanensis were estimated by ELEFAN I in FiSAT Ⅱ software, and the population dynamics was analyzed by the Beverton-Holt dynamic model. The estimated results of von Bertalanffy growth equation was L_∞=304.5 mm, K=0.49/year, and t₀= –0.29. The age inflection point of H. hainanensis was 1.95 years, while the body length was 202.9 mm. Natural mortality was 1.05/year using the empirical formula proposed by Pauly. The fishing (F) and total mortality (Z) coefficients were 0.17 and 1.22/year based on length-converted catch curve method, respectively. The exploitation rate (E) was 0.14, indicating a minimal fishing effect. It is the first time to explore the population growth and dynamic characteristics of H. hainanensis in the upper Nandu River, and this finding would provide a theoretical basis for the recovery and conservation of its population.