%A LIU Jiang-bi, LUO Zhi-xue %T Optimal control for a nonlinear diffusion system with age-dependent %0 Journal Article %D 2016 %J JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) %R 10.6040/j.issn.1671-9352.0.2016.017 %P 136-142 %V 51 %N 5 %U {http://lxbwk.njournal.sdu.edu.cn/CN/abstract/article_2588.shtml} %8 2016-05-20 %X In this paper, we investigate the optimal harvesting for a class of nonlinear diffusion problem in an age-dependent population system with fertility and mortality depending on the population size. Making the maximum revenue from harvested by control the proportion of the species harvested. Mazurīž‘s theory is used to obtain existence of an optimal control. Optimality conditions are derived by means of normal cone technique. Some results in references are extended.