Traverse City Record-Eagle

Archive: Saturday

November 24, 2012

EPA grant to fund sea lamprey testing

LANSING — A $392,000 Environmental Protection Agency grant will pay for testing sea lamprey repellent on three to-be-named spawning streams in the state.

The project is expected to be completed within the 10 years the EPA requires.

Sea lamprey are attracted to the smell of their young and repulsed by the stench of their dead, said Michael Wagner, lead researcher on the project and an assistant professor of fisheries and wildlife at Michigan State University.

Those facts are key to controlling the troublesome invasive species, he said.

Sea lamprey are parasitic, eel-shaped fish that attach to larger fish with suction mouths. Their sharp tongues lash their prey and they feed on the blood of their victims, which then often die from blood loss or infections.

Left unchecked, lamprey threaten both the ecosystem and commercial fishing in the Great Lakes, Wagner said.

What makes them easy to manipulate is that they rely on chemical information from pheromones above all other senses, Wagner said.

"The lamprey are basically a swimming nose," said Marc Gaden, the communications director for the Great Lakes Fishery Commission, a joint U.S-Canadian agency based in Ann Arbor.

Lamprey larvae are blind and live in streams for four to six years before growing teeth and heading into the Great Lakes to suck fish blood. Eventually, they return to reproduce.

They don't return to the same stream they were born in. Instead, they rely on the smell of lamprey young to guide them.

Adults die after spawning and the only way they can protect their young is to leave them in a safe area. That's why they're attracted to the smell of lamprey young, Wagner said. Any stream with that smell should be a good place for the young to survive.

Researchers hope the dead lamprey scent can play a role by blocking each diverging stream. If they can corral all the lamprey in a few selected spots, it's easier to kill them because it's too costly and labor-intensive to control all potential habitats.

Lamprey are active primarily at night, so researchers know exactly when to apply the repellent.

That's good, Wagner said, because if the repellent were constantly present, lamprey would get used to it and ignore it.

The tests, if successful, will bring control closer to what Wagner calls the ideal: a program where sea lamprey can be targeted without damaging the rest of the ecosystem.

Instead of poisoning multiple rivers and potentially harming many species, damage will be dealt almost exclusively to lamprey populations.

"If this works, you've achieved the holy grail of government environmental management programs," Wagner said. "You've managed to make the program more efficient without increasing the cost."

Dmitri Barvinok writes for Michigan State University's Capital News Service.

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