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
Ripon Canal which utilises the towpath from Rhodesfield Lock to Oxclose Lock, although the towpath cannot be used by cyclists. Ripon Canal The Ripon Canal is located in North Yorkshire, England. It was built by the canal engineer William Jessop to link the city of Ripon with the navigable section of the River Ure at Oxclose Lock, from where boats could reach York and Hull. It opened in 1773, and was a moderate success. It was sold to the Leeds and Thirsk Railway in 1847, and was effectively closed by 1906, due to neglect. It was not nationalised with most canals and