秀丽高原鳅种群生存力分析及最小可存活种群数估算

秀丽高原鳅(Triplophysa venusta)系金沙江的土著种, 是云南省重要保护鱼类; 由于其栖息水域建设水电站, 加之云南连年干旱, 导致其种群数量锐减。采用漩涡模型对不同生境下的秀丽高原鳅种群生存力进行了模拟分析, 并估算了其最小可存活种群数。结果表明: 灾害是影响种群长期存活的关键因子, 种群繁殖率和性未成熟个体死亡率对种群生存力影响较大, 而种群的环境容纳量大小则无显著影响; 若连续进行40年的成鱼捕获(2000尾/年), 可使种群在100年内的灭绝概率增至100%, 而若连续进行20年的人工增殖放流(1000尾1龄鱼/年), 可使100年内的灭绝概率降至35.8%。通过模拟计算, 使种群在当前生境下以95%的概率存活100年所需的最小种群数为16000尾。由此可见, 减少灾害发生频率、降低性未成熟个体死亡率、增加繁殖率以及进行人工增殖放流是秀丽高原鳅种群保护与恢复的有效措施。研究为秀丽高原鳅种群保护、渔政管理与人工增殖放流提供了理论依据。

A STUDY ON POPULATION VIABILITY ANALYSIS AND ESTIMATION OF MINIMUM VIABLE POPULATION INTRIPLOPHYSA VENUSTA

Triplophysa venusta, one of the native fish species of Jinsha River with well conserved in Yunnan province, have been dramatically decreased because of the construction of hydropower station in its natural habitat and the con-tinuous drought in Yunnan province. In this study, the population viability analysis (PVA) forT. venusta was simulated by VORTEX model under different scenarios. Its minimum viable population (MVP) was also estimated. The results suggested that catastrophe is the key factor for population survival. The population reproductive rate and the mortality of immature individuals are also important factors that affected the population viability inT. venusta. In contrast, there was no significant influence by environmental carrying capacity on population viability. Moreover, the continuing har-vest of 2000 mature individuals per year for 40 years could make 100% extinction in 100 years. In contrast, the extinc-tion probability could reduce to 35.8% in 100 years by the continuing supplementation of 1000 one-year-old indivi-duals per year for 20 years. Simulation analysis using VORTEX model suggested that 16000 individuals could permit a survival of 95% probability in 100 years and it is the MVP inT. venusta. Consequently, our study displays that the ef-fective methods of conservation and recovery inT. venusta are diminishing the frequency of catastrophe, cutting the im-mature individual mortality, and increasing the population fecundity. This study provides a good theoretical foundation for population protection, fishery management, as well as artificial breeding and releasing forT. venusta.