Lamprey eels

Questions regarding the Flora and Fauna on the island.

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Lamprey eels

Post by johnhens »

Island Interrupted: It Crept in from the Sea

Does one event have the ability to change everything?

The first reported sea lamprey harvested in Lake Superior was taken in August of 1946. It was found at Rock Harbor, described as an “immature adult” at 9.5 inches long. Dr. John Van Oosten, a renowned aquatic biologist of the US Fish and Wildlife Service, made the following comment upon verifying the Isle Royale catch. “If the sea lampreys multiply enough to deplete the lake trout in Lake Superior, the commercial fishermen in that lake will be ruined.” His words were prescient. By the mid-1960s, catches of trout in Lake Superior had dropped to under five percent of their pre-1946 yields. Barely a shadow of the Lake Superior fishing industry remained. All commercial fishing at Isle Royale ground to a halt.

There have been heroic efforts to control the sea lampreys. Binational cooperation has reduced the Great Lakes’ lamprey population by about 90 percent from its peak. Yet the Great Lakes Fishery Commission is not quick to declare victory, instead advocating for continued control of lampreys and recognizing them as “resilient beasts.” Compounded with the introduction other invasive species, native lake trout populations still do not come close to resembling what they were, brimming in the waters of Isle Royale a century ago.

A species arrived, and an entire ecosystem along with a way of life completely shifted. It ought to remind us to have the vigilance to make every effort to protect special places like the interior lakes of Isle Royale. Drying down boats and fishing gear, backwashing filters can mean the difference between a flourishing ecosystem and disaster. Just one modifier has the power to make the island experience very different for generations to come.

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