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
Krivaja (Great Bačka Canal) At the town of Srbobran, the Krivaja turns east, carving a shallow, 15 km long valley, in which it meanders for 33 km before it empties into the Great Bačka Canal, part of the Canal Danube-Tisa-Danube. Total meandering ratio of the whole river is 65:109 (in the valley 15:33), thus the name ("Krivaja"; Serbian for "winding river"). The village of Turija stands on the Krivaja's mouth into the canal, at an altitude of 76 m. The Krivaja drains an area of 956 km, belongs to the Black Sea drainage basin and it is not navigable. Krivaja (Great Bačka Canal) The