The biological relationship between the growth for the fish population and the size of the fish population is g=155(15/5) Where g is the growth of the fish population and S is the size of the population. The size of the harvest is a function of the amount of human affort expended b=3ES Where E is the level of effort. Market price of frsh per unit is $100 and a constant marginal cost of effort is $50. Total revenue from catch in terms of sustainable effort level is $ bs=5 Then, the net benefit function is