Summertime in the Great Lakes means a whole lot of fishing going on. Many people pick up a pole and head to water to enjoy the Great Lakes fishery, which has been one of the largest freshwater fisheries in the world for over 100 years. The greatest Great Lakes commercial fishing harvests were recorded in 1889 and 1899, with about 147 million pounds o fish. Since then, the fishery has been impacted y several threats, including overfishing,water pollution, and the introduction of non-native species to Great Lakes waters. Recent years, however, have seen fishery improvements - walleye fisheries are recovering in Lake Erie, trout populations have become more self-sustaining in Lake Superior, and new salmon fisheries are developing in Lake Ontario. Fishery researchers estimate that 25 to 40 percent of the salmon and trout populations in Lakes Michigan,Huron, and Ontario are now self-reproducing, tanks to improved habitat, water quality, and stream conditions.