The Sea Lamprey
A native of the Atlantic Ocean, Sea Lamprey have been a problem for Great Lakes fisheries for well over 100 years. As adults, they travel up rivers and streams in spring to spawn. The larva live in the organic matter of stream bottoms for several years. When ready, the larva transform into adults and migrate down to the open lake where they prey on fish, latching on with their mouths and drinking the blood of their prey. The prey fish often die from infection that enters through the wound caused by the Lamprey.
Biologists use a variety of techniques to control Sea Lamprey populations and reduce their impact on fish populations in the Great Lakes.