Numerical Simulation for Optimal Harvesting Strategies of Fish Stock in Fluctuating Environment

The population size of fish stock is affected by the variability of its environment, both biologic and economic. The classical logistic growth equation is applied to simulate fish population dynamics. Environmental variation was included in the optimization of harvest to obtain a relation in which the maximum sustainable yield and biomass varied as the environment varied. The fluctuating environment is characterized by the variation of the intrinsic growth rate and environmental carrying capacity. The stochastic properties of environment variables are simplified as normal distribution. The influence of stochastic properties of environment variables to population size of fish stock is discussed. The investigation results relation can be applied for management of fisheries at the optimum levels in a fluctuating environment.