<P> Lake Erie is home to one of the world's largest freshwater commercial fisheries . Lake Erie's fish populations are the most abundant of the Great Lakes, partially because of the lake's relatively mild temperatures and plentiful supply of plankton, which is the basic building block of the food chain . The lake's fish population accounts for an estimated 50% of all fish inhabiting the Great Lakes . The lake is "loaded with superstars" such as steelhead, walleye (American usage) or pickerel (Canadian usage), smallmouth bass, perch, as well as bass, trout, salmon, whitefesh, smelt, and many others . The lake consists of a long list of well established introduced species . Common non-indigenous fish species include the rainbow smelt, alewife, white perch and common carp . Non-native sport fish such as rainbow trout and brown trout are stocked specifically for anglers to catch . Attempts failed to stock coho salmon and its numbers are once again dwindling . Commercial landings are dominated by yellow perch and walleye, with substantial quantities of rainbow smelt and white bass also taken . Anglers target walleye and yellow perch, with some effort directed at rainbow trout . A variety of other species are taken in smaller quantities by both commercial and sport fleets . </P> <P> Up until the end of the 1950s, the most commonly caught commercial fish (more than 50% of the commercial catch) was a subspecies of the walleye known as the blue walleye (Sander vitreus glaucus) sometimes erroneously called "blue pike". In the 1970s and 1980s, as pollution in the lake declined, counts of walleyes which were caught grew from 112,000 in 1975 to 4.1 million in 1985, with estimates of the numbers of walleyes in the lake at around 33 million in the basin, with many of 8 pounds or more . Not all walleyes thrived . The combination of overfishing and the eutrophication of the lake by pollution caused the population to collapse, and in the mid-1980s, one species of walleye called the blue walleye was declared extinct . But the Lake Erie walleye was reportedly having record numbers, even in 1989, according to one report . There have been concerns about rising levels of mercury in walleye fish; a study by the Canadian Ministry of the Environment noted an "increasing concentration trend" but that limits were within acceptable established by authorities in Pennsylvania . It was recommended, because of PCBs, that persons eat no more than one walleye meal per month . Because of these and other concerns, in 1990, the National Wildlife Federation was on the verge of having a "negative fish consumption advisory" for walleyes and smallmouth bass, which had been the bread - and - butter catch of an $800 million commercial fishing industry . </P> <P> The longest fish in Lake Erie is reportedly the sturgeon which can grow to ten feet long and weight 300 pounds, but it is an endangered species and mostly lives on the bottom of the lake . In 2009, there was a confirmed instance of a sturgeon being caught, which was returned to the lake alive, and there are hopes that the population of sturgeons is resurging . </P> <P> Estimates vary about the fishing market for the Great Lakes region . One estimate of the total market for fishing, including commercial as well as sport or recreational fishing, for all of the Great Lakes, was $4 billion annually, in 2007 . A second estimate was that the fishing industry was valued at more than $7 billion . </P>

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