A sea lamprey, the first invasive species in the Great Lakes. (Photo courtesy of the USEPA)
One of the most destructive invasive species in the Great Lakes was also the first one to arrive. The sea lamprey invaded the Lakes more than a hundred years ago, and no one’s been able to get rid of it. As Rebecca Williams reports, it’s the only invader in the Lakes that managers have been able to control… but it takes millions of taxpayers’ dollars every year to keep the blood-sucking parasite in check, and there’s no end in sight:
Transcript
One of the most destructive invasive species in the Great Lakes was also the first one to arrive. The sea lamprey invaded the Lakes more than a hundred years ago, and no one’s been able to get rid of it. As Rebecca Williams reports, it’s the only invader in the Lakes that managers have been able to control… but it takes millions of taxpayers’ dollars every year to keep the blood-sucking parasite in check, and there’s no end in sight:
(Sounds of tank bubbling)
There’s a sea lamprey sucking on Marc Gaden’s hand.
“You can see he’s really got my thumb now, I’ll try and pull him off my thumb – this is a suction cup (popping sound of lamprey being detached).”
Gaden is with the Great Lakes Fishery Commission. It’s a group that was created by the US and Canadian governments with one main purpose: to control the sea lamprey. Gaden isn’t in any actual danger when a lamprey’s hanging on him. They don’t feed on warm-blooded creatures. But fish are another story.
“The mouth is ringed with sharp teeth, row after row of these sharp teeth, and in the middle of the mouth there is a tongue that flicks out and it’s sharp as a razor. What that tongue does is files its way through the side of the fish’s scales and skin and then the sea lamprey has access to blood and body fluids of the fish and that’s what it does, it feeds on them.”
Sea lamprey get fat drinking fish blood and fluids. They leave bloody holes in the side of fish, wounds that often kill the fish. Each lamprey can kill 40 pounds of fish a year.
Lamprey got into the lakes through manmade canals that connected to the Atlantic Ocean. By the 1940’s, the exotic species had invaded every one of the Great Lakes. Marc Gaden says by the 1950’s, lampreys had killed off most of the big predator fish in the Lakes.
“There’s literature around that time period that talked about gaping bloody wounds that commercial fishermen were finding on their catch, the commercial catch was beginning to go down the tubes, also because of overfishing, but sea lamprey was a major cause of that decline.”
Paul Jensen’s family used to fish for the popular lake trout before the lamprey wiped them out. Jensen now fishes for whitefish. He’s one of a small pool of commercial fishers who still pull a living from the Lakes.
“Every port along southern Michigan had commercial fishermen. South Haven, St. Joseph, Ludington, Manistee… There aren’t any, they’re gone. And one of the main reasons they’re gone, I think can be traced back to sea lamprey.”
Jensen says most commercial fishers these days have to do more than catch fish. He also runs a marina and builds research boats. Jensen says commercial fishers either had to adapt to the changes the lampreys brought or get out of the business.
“The whole food chain has just been devastated and turned upside down by exotics, and it’s been kind of a mystery; we have no clue as to where it’s gonna go. We’re glad with what we’re getting but I don’t know if we have much control of where it’s going.”
The people who manage fisheries have been wrestling for control over the sea lamprey. Marc Gaden says the lamprey control program has reduced the parasites’ numbers by 90 percent over the past 50 years. But he says lampreys have recently rebounded above target levels in several areas of the Great Lakes.
“It goes to show you these are crafty beasts. Even though they’re primitive and haven’t evolved much since the time of the dinosaurs, they still will find ways in which to spread and find new stream habitats and we always have to try our best to stay one step ahead of them.”
Gaden says the fishery commission has been aggressively treating the areas where lamprey numbers are too high. The main method is a lampricide that kills lamprey when they spawn in streams. Researchers are also working on chemical attractants to lure lampreys into traps.
But all of this takes money. Since the 1950’s, the US and Canada have spent about $300 million to keep lampreys in check. Marc Gaden says that sounds like a lot of money, until you look at the value of the fishery. It’s valued at about 4 billion dollars a year.
“So the amount of money we spend, upwards of 20 million a year, to keep lampreys under control, is a tiny fraction of the value of that fishery. But nevertheless it’s a cost we’re going to have to endure in perpetuity because the lampreys are not going away.”
But the Bush Administration’s proposed budget cut some of the funding for lamprey control. The fishery commission is hopeful that Congress will restore the funding. Marc Gaden says if we want any sport fishing, any tribal fishing, any commercial fishing… lampreys have to be kept under control, and that takes steady funding from Congress.
For the Environment Report, I’m Rebecca Williams.