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
Cumberland and Oxford Canal Cumberland and Oxford Canal The Cumberland and Oxford Canal was opened in 1832 to connect the largest lakes of southern Maine with the seaport of Portland, Maine. The canal followed the Presumpscot River from Sebago Lake through the towns of Standish, Windham, Gorham, and Westbrook. The Canal diverged from the river at Westbrook to reach the navigable Fore River estuary and Portland Harbor. The canal required 27 locks to reach Sebago Lake at an elevation of above sea level. One additional lock was constructed in the Songo River to provide of additional elevation to reach Long Lake from Sebago Lake.