Great Lakes Article:

Sea lamprey gets new status: Vermont native
By Candace Page
Burlingston Free Press
Published November 29, 2005

If Lake Champlain's sea lamprey could talk through those ugly, tooth-filled, blood-sucking mouths of theirs, here's what they'd be saying to Vermonters: "Nyah, nyah, nyah, you newcomer flatlanders you."

Yes, it's true: Sea lamprey, long the lead villains on Vermont's Most Unwanted list of invasive species, turn out to be natives after all.

A team of Michigan State University researchers has established that Lake Champlain lamprey are a genetically distinct population old enough to be defined as native. The eel-like fish probably swam up the St. Lawrence and Richelieu rivers from the Atlantic Ocean and became landlocked in Lake Champlain as long ago as 11,500 years, the researchers concluded.

"The evidence is convincing," said Brad Young, a fishery biologist at the U.S. Department of Fish and Wildlife in Essex Junction. "They have invasive-like characteristics, but they are natives."

This is less than wonderful news for Vermont anglers.

"Even if they are native, they are ruining what we are trying to do to get the lake fishing back to what it should be," said Ed Braman of Colchester, an avid fisherman of salmon, lake trout and walleye.

He said he feared the lamprey's new status would provide fuel to those who want to stop Vermont's treatment of streams with lamprey-killing chemicals.

But government biologists said they are not inclined to give the "new" native a break.

"Unequivocally no," Young said. "Whether it is a native or an invasive species does not affect our position. We need to suppress the lamprey population to support re-establishment of the fishery for salmon and lake trout."

Champlain's lamprey numbers exploded in the past three decades. Adult lampreys clamp their toothy, jawless mouths on salmon and trout to suck their blood. At best, they leave an ugly wound. At worst, they kill smaller and younger fish.

The lamprey's newly established native status does generate a new mystery: How did healthy populations of trout, salmon and lamprey co-exist for thousands of years, and then get so out of balance in the past 30 years?

Vermont's new natives

Some Vermont biologists have argued for some time that lamprey are native to the lake. Their case was weakened by the fact that there were no reports of lamprey -- or of lamprey wounds on trout -- until the mid-1800s.

In the majority view, lamprey were a recent invader that reached the lake by running up the Hudson River and through the Champlain Canal after it opened in 1823.

Now comes Mara Bryan, a postdoctoral fellow and sea lamprey researcher at Michigan State. She and a team set out to compare the genetics of lamprey populations in the five Great Lakes, Lake Champlain, New York's Lake Cayuga and the Atlantic Ocean. They published their results recently in a scientific journal, Molecular Ecology.

They examined DNA from 741 lamprey, including ones taken from Lewis Creek in Vermont and the Great Chazy River on the New York side of the lake.

"The Lake Champlain lamprey were very different from everything else, and it takes a good amount of time for things to become different," Bryan said.

"I'm 99.99 percent absolutely sure they have been here longer than European settlers. The science is very good on this," she said.
From native to pest

If lamprey have been in Lake Champlain so long, why have they only recently become a pest?

"That's the $64 million question," said Mike Winslow, a biologist at the Lake Champlain Committee in Burlington. Human beings probably are as much to blame as the lamprey, he and others said.

"It's likely lamprey were present in fairly low numbers previous to us messing things up," Bryan said. Native species like trout might have evolved ways to co-exist with lamprey.

Brian Chipman, a fisheries biologist at the state Fish and Wildlife Department, summed up the most common theory for the lamprey population explosion in recent years:

In the 1800s, Vermont's new residents dammed up salmon-spawning rivers that run to the lake and dumped sewage, sawdust and other pollutants into the rivers. Commercial fishing businesses swept trout from the lake with nets and spears.

By the early 20th century, salmon and trout populations had crashed. Lamprey numbers probably crashed, too -- their main prey was gone and, like the salmon, their river spawning grounds had been polluted -- so they were seldom seen during the first half of the 20th century.

Then humans began to clean up rivers in the Champlain basin. State governments started restocking the lake with thousands of young lake trout and landlocked salmon -- a feast for lampreys.

"We expanded their food supply and improved water quality where they spawn," Chipman said. "They responded to that."

Controlling a nuisance

No one knows how many lamprey live in Lake Champlain.

"I'd say from tens of thousands to hundreds of thousands, but it's hard to quantify," said Young, the federal biologist.

Rather than counting lamprey, biologists count the number of fresh lamprey wounds they find on lake trout every fall. Without lamprey control, biologists routinely find 60 or 70 wounds for every 100 trout they examine.

When Vermont and New York ran a control program in the 1990s, the wounding rate fell as low as 30 per 100 fish. The control program stopped, and the wound rate skyrocketed, peaking at 90 wounds in 2003. The goal is to reduce the wounding rate on lake trout to 25 per 100 lake trout, Young said.

Lamprey might be natives, but their numbers are out of balance for the ecosystem, Chipman and Young said.

Young said his agency would never set out to eliminate a native species -- but no one thinks it is feasible to extirpate lamprey in any case.

"We just want to manage their numbers to serve our fishery restoration goals," Chipman said.

If lamprey have moved from the "invasive" list, they've joined a substantial list of native species that humans manage to prevent overpopulation or nuisances -- cormorants that have killed all other life on several Champlain islands, whitetail deer that can overbrowse their range, beavers whose dams flood roads and fields.

For lamprey, control means a regular schedule of chemically treating rivers in New York and Vermont to kill the mud-buried lamprey larvae. Those treatments have run into objections from some environmental groups on grounds they could kill other species in the rivers, a stand that makes some anglers furious.

"Native" is usually a desirable adjective in Vermont. So can no one find a kind word to say about lamprey? Maybe not.

"I think it is hard to quantify the benefit or role of lamprey," biologist Young said.

Fisherman Braman thought for a minute. Don't people in some cultures consider lamprey good eating? he asked.

"If they do, they can have them," he said.

Contact Candace Page at 660-1865 or cpage@bfp.burlingtonfreepress.com