Question: The owner of an artificial lake, which has been created with the main aim of making a commercial return from recreational fishing, has to decide how many fish to stock the lake with. Allowing for the natural rate of growth of the fish population and the depletion caused by fishing, the number of fish in the lake is expected to shrink continuously by 3.2% a year. How many fish should the owner stock the lake with if they wish to ensure that the fish population will still be 500 in 5 years' time, given that it will not be viable to add more fish after the initial stock is introduced?