The Great Lakes are no strangers to invasive species and the U.S. Fish and Wildlife Service has become adept at battling these creatures whose mere presence can often be catastrophic.
One such species that needs to be culled from time to time is the sea lamprey, which resembles an eel and has a circular mouth with teeth used to suction itself to other fish and suck their blood. The USFWS spent time this week surveilling Harlow Lake, catching larvae and preventing them from growing into adults and migrating into Lake Superior.
Lynn Kanieski, a fish biologist with the USFWS, said, “We’re using a chemical called granular Bayluscide. It’s a sand granule that has a chemical coding so what we do is we hand spread it into the lake and the sand granule sinks to the bottom and slowly releases and the larvae get irritated and they come up to the surface and we collect them and they die.”
The team plotted out where to disperse the lampricide with range finders and buoys, then spent about an hour drifting through the area, waiting for any lamprey to surface. Lamprey may be harmless to people, but if they managed to get into Lake Superior they could devastate the fish population.
“The lamprey will head out into the Great Lakes; one adult lamprey can kill 40 pounds of fish. If we did not control the lamprey we would not have a fishery in the Great Lakes,” Kanieski said.
The good news is fewer lamprey have been collected with each survey over the years. There used to be hundreds collected, but recent surveys haven’t broken out of the single digits.
The USFWS assesses the lamprey population every three to five years and the most recent collection yielded zero lamprey, which is not uncommon.