刺网选择性对鱼类表型性状的选择作用研究

本研究从刺网选择性对鱼类表型性状的影响入手,应用数值模拟方法,模拟了一个具有一定体长特征的鱼类种群,利用具有多项选择参数(曲线标准差σ,最适体长l0,选择性因素R0)的刺网曲线对其进行长期捕捞作用,并在去除捕捞的情况下探讨这种影响的稳定性。结果表明,刺网捕捞作业长期作用于鱼类种群,会对种群体长组成产生深远的影响,开发率(E)越大,效果越明显。当刺网最适捕捞体长与初始种群优势体长重合时(l0=15),造成种群体长分布峰值的分化;如果l0>15,则导致种群体长组成向小型化方向偏移;反之则会造成种群体长组成向大型化方向偏移;而且这种影响可能伴随遗传因素,具有不可逆性。

A STUDY ON THE IMPACT OF GILLNET ON THE PHENOTYPIC TRAITS OF FISH POPULATION

Based on models used in fishery biology,quantitative genetics,as well as numerical simulation methods,we developed a numerical simulation model to investigate whether long-term use of gillnet may affect the phenotypic traits(such as body length) of a fish population.In our simulation,we modeled a fish population that had a certain body length;then by varying a host of variables(σ,l 0,R 0),we explored the effect of long-term gillnet fishing as well as examined the stability of such effect after the fishing pressure was removed.The simulation results suggested that long-term fishing pressure was able to affect the characteristics of the fish population,i.e.,the lager the exploitation rate(E),the more distinct the effect.Furthermore,this impact was probably irreversible for a population that had experienced long-term fishing pressure.