The sea lamprey is an invasive species that is parasitic to trout in Lake Superior. The graph below shows the population of trout in Lake Superior between 1930 and 1994. Trout in Lake Superior Modified from image courtesy of USGS Sea lampreys were likely introduced to Lake Superior in (1935, 1955, 1970, or 1985). A program to reduce and control the population of sea lampreys was likely started in (1935, 1950, 1965, or 1985).

Sorry i don't know how to add the graph.