The visual above shows a dashed line that represents the amount of the harvested item, for this example it will be fish. The line on above the dashed line shows the total population of that fish species. With this also comes the intrinsic rate of growth shown at the top of the dashed line. This is the point at which the population should be kept in order to maximize the growth of new individuals and in turn, maximize profits. So it simply comes down to maximizing the amount of fish that can be taken to market and it brings in the most amount of money to the producer.