This graph showcases the sea lamprey and lake trout population from 1930 to 1990. The lake trout is shown in red and the sea lampreys are shown in blue. As you can see, the lake trout were plentiful, and then the sea lampreys came and depleted much of the population. Though, eventually the population was very low, so many of sea lampreys moved away to try and find more food, giving some time for the lake trout to repopulate their population.