The graph shows that in 1990 there was only one fishing boat and a large quantity of fish. Five years later there was a large quantity of fishing boats but only one fish left. The drawer is indicating that over the years the waters have been over-fished. In 1990 only one boat was fishing those waters and supply was great. Five years later, many more boats began fishing in the same area and depleted the fish population.
This is a common situation: people or companies see an untapped market and exploit it until it becomes useless. Ideally the situation would remain stable somewhere in the middle of these two graphs. There would be enough boats to gather a reasonable amount of fish, but not enough that they would eliminate them. This situation could be controlled by certain regulations. If the area were monitored carefully this problem could have been avoided and more people could have benefited. Because it was not monitored, everyone loses.