Through the canals came the sea lampreys, and life in the lake has been out of kilter ever since.
The chemical assault is aided by the sea lamprey's physiology and life cycle.
The decline of the species has been largely caused by overfishing and predation from the invading sea lamprey.
The sea lamprey is an eel-like parasite that attaches itself to sport fish and can kill them.
The fish stocks also collapsed with the introduction of the sea lamprey into the Great Lakes.
In place of a jaw, the sea lamprey has a sucking disk around its mouth.
Most sea lampreys migrate from open water around this time of year to small tributary streams where they spawn and die.
The sea lamprey is not a big problem on the East Coast.
I don't think you'd want to eat a sea lamprey yourself, but they were about all that was left in the lake.
In contrast, the most notorious species is the sea lamprey, Petromyzon marinus.