1. Suppose that a fishery is characterized by the following relationship between total fish stock and annual growth:

STOCK 10 20 30 40 50 60 70 80 90 100 120

(thousand tons biomass)

GROWTH 0 800 1,600 2,400 2,800 3,000 2,800 2,200 1,200 0 –1,200

(tons)

Construct one graph showing the relationship between stock and growth and another graph showing the growth rate at each stock level (e.g., at stock = 60,000 tons, yield = 3,000 tons, growth rate = 5 percent). What stock level corresponds to the maximum growth rate? What stock level gives the maximum sustainable yield? What will be the stable and unstable equilibrium stock levels for this fish population in a natural state?