渔捞对捕捞资源的作用有两种基本类型。一种是自然死亡和捕捞死亡全年同时出现,并以恒定的瞬时率作用于种群,全年进行捕捞的渔业可看作属于这一类型。另一种是一年分为两个时期:一个时期是捕捞死亡和自然死亡同时作用于种群;另一个时期则没有捕捞死亡,种群仅受自然死亡的作用,季节性渔业属于这一类型。Beverton-Holt产量模式适用于第一类型,用于第二类型则受到限制。Ricker估算平衡渔获量的方法是以分阶段计算为基础的, There are two basic types of effects of fishing on fishing resources. One is that natural and fishing fatalities occur simultaneously throughout the year and act on the population at a constant instantaneous rate and that fishing for the year can be considered as belonging to this category. The other is a year divided into two periods: one period is fishing and natural death at the same time acting on the population; the other period, there is no fishing death, the population is only natural death, seasonal fisheries belong to this type. Beverton-Holt production mode is suitable for the first type, for the second type is limited. Ricker’s method of estimating catch is based on a staged calculation,