Lurking in the waters of the Great Lakes is a parasite that forever changed the native ecosystem. The saw–toothed suckers were introduced into the Great Lakes over a century ago.
Doug Jensen, from University Minnesota Sea Grant Duluth told me, "The lamprey is really considered the Vampire of the Great Lakes. It uses its sucking mouth and rows of teeth to latch on to the side of the fish, suck the blood and body juices out of the fish usually killing it"
Once the population of Lamprey grew, the effects on the natural species were devastating.
"Following the introduction of the sea lamprey the harvest of lake trout in Lake Superior went from 4 to 6 million pounds annually to virtually nothing in the 1950's." says Jensen.
In 1958 the Fisheries Commission was created and by 1959 they had come up with a solution to deal with the toothy invasive.
Jensen told me, "The Achilles Heel for sea lamprey control is that this phase, that's in April and May, when the water temperatures begins to warm up and the Sea Lamprey begin to migrate and concentrate in an area, that provides an opportunity for control."
During this time a chemical called TFM is used to selectively kill the Lamprey, and not natives. But once introduced, an invasive species is never fully eradicated.
"Its estimated that there's about 800–thousand parasitic lamprey in the Great Lakes at this time." says Jensen.
This is only about 10% of the population in 1950. The first devastating invasive paved the way to new regulations and laws meant to stop new species from invading the Great Lakes.
"Since 2006 there's been no new species that have been introduced into the Great Lakes that have caused invasive impacts. That tells us that we are beginning to shut down the pathways." said Jensen.
Only 1 out of 6 fish survive a Sea Lamprey attack. If you ever encounter a strange or exotic fish you are urged to call the DNR and report it.