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
Oswego River (New York) overhaul of the canal system, the Oswego Canal was deepened and refurbished. The canal is now deep and has an overhead clearance of . The Oswego River was listed as a Great Lakes Areas of Concern in The Great Lakes Water Quality Agreement between the United States and Canada until it was formally delisted on July 21, 2006. The river is known for its steelhead run in the early spring, followed by a salmon run in early autumn. The river is stocked annually by the New York State Department of Environmental Conservation with 140,000 Chinook salmon and 20,000 steelhead. Oswego