A STUDY ON THE IMPACT OF GILLNET ON THE PHENOTYPIC TRAITS OF FISH POPULATION
刺网选择性对鱼类表型性状的选择作用研究

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.