Inside the Hunt for a Great Lakes Blood Sucker

  • A sea lamprey wound on a steelhead trout found in New York. Photo: Alberto Ray, U.S. Fish and Wildlife Service

June 26, 2015

If you ever get a chance to meet a sea lamprey, you won’t forget it. They have a suction cup for a face, with hundreds of razor-sharp teeth.

“Yeah, they’re ugly, but in the same regard, functionally, they’re kind of beautiful,” says Jason Krebill, who’s been chasing lamprey larvae for 15 years as part of a federal eradication program.

“As far as parasites go, they get a free meal and a free ride for the majority of their life. I think they sacrifice looks for smarts.”

This is the time of year when teams from the federal government hunt for sea lamprey babies. Sea lamprey invaded the Great Lakes in the early 20th century and no one’s been able to get rid of them. Aaron Jubar, a fish biologist with the U.S. Fish and Wildlife Service, says they attach to fish and actually rasp a hole through the skin and scales to feed on blood and bodily fluids.

“We estimate a single sea lamprey in the Great Lakes can destroy up to 40 pounds of Great Lakes fish through its parasitic life, which is only about 18 months,” Jubar says.

They love to feed on lake trout, salmon, whitefish and steelhead—prize fish at the top of the food web in the Great Lakes. The federal government spends more than $20 million dollars each year to control the lamprey—much of it on the control program that hunts down lamprey when they’re still young.

The mouth of a sea lamprey is basically a suction cup filled with razor-sharp teeth. It's perfectly adpated to latching onto fish and burrowing into their flesh. Photo: U.s. Environmental Protection Agency

The mouth of a sea lamprey is basically a suction cup filled with razor-sharp teeth. It's perfectly adpated to latching onto fish and burrowing into their flesh. Photo: U.s. Environmental Protection Agency

Aaron Jubar and his team look a little like Ghostbusters when they head out on their lamprey hunt on the Clinton River in southeast Michigan. They are wearing waders and gloves and have metal contraptions strapped to their backs.

“What we’re using today is our backpack electro-fishing units and these are specially designed to capture sea lamprey larvae.”

The backpacks send an electric current down through two metal probes. The crew members then move these through the water looking for lampreys.

“And then that low pulse agitates them so they come shooting up out of their burrows. When we see them, then we can high pulse and that actually completely immobilizes them and then we can scoop them up.”

With the electric pulse moving through the river, Jubar's team has to be careful not to actually touch the water.

“You would definitely feel it. The low pulse would be a sharp tingling; the high pulse, you’d feel that shoot up your arm.”

The U.S. lamprey hunting teams do 2,000 of these surveys all over the Great Lakes region every summer. And there are more of these teams working the Canadian side of the lakes. They’re trying to get a better sense of where the lampreys are. If they find them, different crews come out and kill the lampreys with a lampricide.

Aaron Jubar says they’re constantly trying to knock back their numbers. It’s a battle that’s been going on since the late 1950s.

“They’re a lot like cockroaches. You leave two behind, you have a problem. Because the females can have up to 100,000 eggs. Just one female and one male can infest this whole stream potentially.”

Teams from the U.S. Fish and Wildlife Service hunt for young sea lamprey in Michigan's Clinton River. Photo: Rebecca Williams, Michigan Radio

Teams from the U.S. Fish and Wildlife Service hunt for young sea lamprey in Michigan's Clinton River. Photo: Rebecca Williams, Michigan Radio

Jubar says they’re keeping the sea lampreys in check in most of the Great Lakes. But in the past six years, lampreys have been booming in Lake Erie. Jubar says as Lake Erie and the rivers that feed it have become cleaner, it’s helped many fish species. But it’s also helped the lamprey thrive.

“In 2014, we estimated just over 14,000 sea lampreys in Lake Erie. So we’re still five times above our target levels.”

Jubar says they’re already treating many streams and rivers around Lake Erie with lampricide, but other rivers that are not treated are probably the reason the lamprey population is still so large here.

“We just aren’t seeing the effect we’d want to in lakewide levels,” Jubar says.

For instance, the St. Clair River in Michigan isn’t treated for lampreys and there are more than 900,000 baby lampreys in that river.

Back on his lamprey hunt on the Clinton River, Jubar is leaving empty-handed—which is actually a good thing.

“We’ve never found them up this far, but we’re very vigilant,” he says.

And they’ll keep doing this work, every single summer, to try to stay on top of this expensive, blood-sucking parasite.