. Commercial fisheries review. Fisheries; Fish trade. Lake Trout Are Back in the Swim The lake trout of Lake Superior, driven close to extinction by the fierce attacks of the eel-like sea lampreys, have been rescued by--man. In 1967, the lake trout were more abundant than at any time in nearly 30 years; they had increased over one-third in just one year. And only 2 percent of the trout exam- ined showed the wounds of the lifesucking lampreys. The lampreys first made their way into the Great Lakes inthe 1940s--and came close to annihilating the lake trout of Lakes Michi- gan, Superior, and Huro
. Commercial fisheries review. Fisheries; Fish trade. Lake Trout Are Back in the Swim The lake trout of Lake Superior, driven close to extinction by the fierce attacks of the eel-like sea lampreys, have been rescued by--man. In 1967, the lake trout were more abundant than at any time in nearly 30 years; they had increased over one-third in just one year. And only 2 percent of the trout exam- ined showed the wounds of the lifesucking lampreys. The lampreys first made their way into the Great Lakes inthe 1940s--and came close to annihilating the lake trout of Lakes Michi- gan, Superior, and Huron. have increased steadily--and the lampreys have declined steadily. Many Streams Treated After Lake Superior, and by the e n d of 1966, all lamprey-infested streams entering Lake Michigan were treated. Hatchery- reared trout fingerlings were first put into the lake in 1965 and have grown well. To aid Lake Huron's trout, lampricide treatment has begun of infested streams in the U. S. and Canada that flow into the lake. Overall, the lampricide has been used on more than 250 infested streams that make their way into the Great Counterattack In 1958, scientists of BCF and the Cana- dian Government launched a 2-fold lamprey- control program, which was administered by the Great Lakes Fishery Commission, A "lampricide," a chemical developed by BCF scientists to kill only the larvae and young of lampreys, was spread through the parts of streams in which lampreys spawn. And, to fill the ravaged ranks of the lake trout, vast quantities of juveniles were put into the affected lake areas. By 1961, in Lake Superior, the tide of bat- tle began to turn. Since then, the lake trout Lamprey Control May Cut Alewives Too LsLmprey control also may aid inthe cam- paign against the unusually abundant herring- like alewife that was a great nuisance to Lake Michigan communities in 1967. Alewives died in great numbers. They were expensive to haul away, forced out some private owners, a
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