Great Lakes are estimated at 900 trillion. The influx of parasitic lamprey populations after the development of the Erie Canal and the much later Welland Canal led to the two federal governments of the US and Canada working on joint proposals to control it. By the mid-1950s, the lake trout populations of Lakes Michigan and Huron were reduced, with the lamprey deemed largely to blame. This led to the launch of the bi-national Great Lakes Fishery Commission. "The Great Lakes: An Environmental Atlas and Resource Book" (1972) noted: "Only pockets remain of the once large commercial fishery." But, water quality improvements realized
Great Lakes region area urban planners call the Great Lakes Megalopolis, which has an estimated 59 million people. Chicago is emerging as the third megacity in the United States, after the New York City and Los Angeles metropolitan areas, with a metro population approaching ten million. Cities along the Great Lakes have access to the Atlantic Ocean through the St. Lawrence Seaway, making them international ports. The Palaeozoic strata, are but parts of a great area of similar strata hundreds of feet in thickness. These strata decline gently southward from the great upland of the Laurentian Highlands of eastern Canada. The visible upland