Mich. (AP) - Parasitic sea lampreys may have established a self-sustaining
population in Michigan’s Inland Waterway, a nearly 40-mile-long chain of
lakes and rivers popular with anglers and boaters, federal scientists said
It would be the
first confirmed case in the Great Lakes region of the invasive lampreys
spending their entire life cycle in an inland waterway network instead of
migrating to one of the lakes after reaching adulthood, said Nick Johnson, a
research ecologist with the U.S. Geological Survey’s Hammond Bay Biological
Station on Lake Huron. That could mean the job of containing them will get
costlier and more complicated, he said.
The findings are
preliminary but show the importance of determining whether the same thing is
happening in other inland lakes, said Marc Gaden, spokesman for the Great
Lakes Fishery Commission, which spends about $21 million a year keeping
lamprey numbers down.
“These critters are
quite destructive,” Gaden said. “If we find they’re having an impact on
inland lakes, or that inland lakes are serving as a source of lamprey for
the Great Lakes proper, we’ll need to address that.”
Tim Cwalinski, a
Michigan Department of Natural Resources fisheries biologist, said it’s
likely that sea lamprey have been living undetected in waterways upstream
from the Great Lakes for years. There’s no evidence they are doing heavy
damage to Inland Waterway fish, he said.
native to the Atlantic, reached the Great Lakes through shipping canals in
the past century and feasted on trout and other prized species. The eel-like
predators fasten their round, disk-like mouths, rimmed with razor-sharp
teeth, to the sides of fish and suck their blood.
lampreys feed for 12 to 20 months before swimming up rivers to spawn, then
dying. Their wormlike offspring spend up to six years as larvae, concealed
in stream beds, before heading to the lakes as adults.
keep them in check with methods such as spreading poisons in rivers and
trapping and sterilizing males. Dams and other barriers help by preventing
them from reaching spawning areas.
Lampreys in their
larval stage have been found for years in three streams that feed Burt and
Mullet lakes, which are part of the Inland Waterway in Cheboygan and Emmet
counties near the tip of Michigan’s Lower Peninsula. Scientists have assumed
they were reaching the waterway by swimming up the Cheboygan River from Lake
Huron and bypassing a lock and dam, although it wasn’t clear how, Johnson
But recent evidence
suggests some lampreys are surviving poison treatments in those streams,
then slipping into Burt and Mullet lakes and remaining there instead of
continuing to Lake Huron, he said. Anglers have provided photos of fish with
lamprey wounds caught in those inland lakes, and an adult lamprey was nabbed
in Burt Lake last August.
“So even if we
identify their escape route around the Cheboygan lock and dam and close that
door, we still may have a battle with sea lamprey to wage in the inland
waterway itself,” Johnson said.
That would be bad
news because the budget for lamprey control is already stretched, Gaden
But a silver lining
would be that agencies could mount an all-out effort and determine whether
it’s possible to completely eliminate lampreys from waterways, Johnson said.
The existing program has knocked down the population by 90 percent, but
experts have considered eradication a pipe dream because a single female can
lay up to 100,000 eggs at once.