中文摘要：

分析一类食饵种群带有尺度结构的种群系统的最优收获问题．利用不动点定理证明了状态系统及其共轭系统非负解的存在唯一性，解对控制变量的连续依赖性．应用切锥法锥技巧导出了最优性条件，借助Ekeland变分原理讨论了最优收获策略的存在唯一性，推广了年龄结构种群模型中的相应结论．

英文摘要：

This work is concerned with an optimal harvesting problem for a predator- prey model, in which the prey population is described by a first order partial differen- tial equation （PDE） in a density function and the predator by an ordinary differential equation in total size. Existence and uniqueness of solutions to the state system and the dual system are proven via fixed point theorem. Necessary optimality conditions of first order are established by use of tangent-normal cones and dual system tech- nique. The existence of a unique optimal control pair is derived by means of Ekeland＇s variational principle. The resulting conclusion extends some existing results involving age-dependent populations.