RAVENNA, Mich. (WOOD) — Biologists are treating West Michigan rivers to fight the invasive sea lamprey and protect native fish species.

Crews from the U.S. Fish and Wildlife Service treated Crockery Creek in Ravenna Friday. The Rogue River in the Rockford area is also being treated.

“Each sea lamprey through its lifecycle can consume and kill about 40 pounds of fish in the Great Lakes,” said Chris Eliers, a supervisory fish biologist.

The USFWS has teams that travels around the Great Lake basin to find and kill invasive sea lamprey.

“They live burrowed into the sediment, so they are very hard to find. We have an assessment team that goes out and searches throughout the Great Lakes tributaries looking for the larvae,” Eliers said.

The sea lamprey is similar to native lamprey, but the invasive species grow larger and can decimate Great Lakes fish species.

“They have a suction cup-like mouth and that mouth attaches right on the side of the fish. It’s a very powerful suction and then they use their tongue to cut a hole in the side of the fish in order to drink their body fluids,” Eliers said.

Crews poured 3-trifluoromethyl-4-nitrophenol, also called TFM, into Crockery Creek, using a small amount that should not harm other fish. They monitored the levels throughout the process.

“Lamprey are a primitive fish that have been around for millions and millions of years so they’re unable to metabolize that chemical, the lampricide, so they essentially die,” said Lauren Freitas, a lampricide treatment supervisor.

The program is effective in helping native fish populations recover.

“Some people think, ‘Well, this doesn’t really affect me. I don’t know there’s sea lamprey here. I’ve never heard of that before.’ And that lets me know we’re doing our job because 60 years ago, our program came about because the lake trout were decimated,” Freitas said.

The Ludington-based team says the work is rewarding because they know they are helping protect Michigan’s waterways.

“It’s very important that we’re taking care of all the invasive species that we can that are affecting the Great Lakes. Invasive species are one of the number one threats to the Great Lakes ecosystem,” Freitas said.

To learn more about the sea lamprey and efforts to control them visit the Great Lakes Fishery Commission website.