Optimal and feedback strategies for managing multicohort populations (Q799466)

A Beverton and Holt type linear cohort dynamics model [see \textit{R. J. Beverton} and \textit{S. J. Holt}, ''On the dynamics of exploited fish populations'', Ministry of Agriculture, Fisheries, and Food, London, England, Fisheries Investigation Series II, vol. 19 (1957)] is integrated and combined with a nonlinear stock-recruitment relationship to obtain a discrete-time multicohort harvesting model. Assuming that each age class is individually controllable, it is shown, subject to certain assumptions, that the optimal harvesting strategy is to derive the population to the maximum substainable yield solution in one time step. In most fisheries, this controllability assumption is not met and harvesting is agewise nonselective. In this case, it may be preferable to implement a harvesting policy based on suboptimal constant effort or stock level feedback strategies, rather than implement a more complicated optimal policy. This question is addressed through numerical studies on the management of the anchovy fishery.