An exploited predatory-prey system is discussed.The conclusions about nonexistence,existence and uniqueness of limit cycles are obtained by using qualitative and bifurcation methods.The significance of the conclusions are interpreted at the same time.

• 讨论了一类食饵种群被开发的两种群捕食系统.；运用定性分析和分支方法给出了该系统极限环的不存在性、存在性和惟一性等结论；并对相应的生态学意义作了说明