Zebra mussels, one of the most notorious
aquatic pests in the nation, have been discovered in a
small New York reservoir that feeds into the Susquehanna
River, and top scientists are meeting today to outline
a plan to prevent them from spreading in the Chesapeake
Bay watershed.
The tiny mollusks, which are native to Europe and
have no natural enemies here, have spread rapidly since
they were brought to the Great Lakes in a ship's
ballast water in the early 1980s. They grow so quickly
that they can clog intake pipes at power plants, factories
and municipal water plants, forcing them to shut down.
A breeding population
of zebra mussels has appeared in a reservoir in Madison
County, N.Y., near the headwaters of the Susquehanna,
said biologist Thomas Horvath of the State University
of New York at Oneonta. The invasive creatures have
apparently been in Eaton Brooke Reservoir since 1999,
Horvath said.
A creek connects the reservoir to a tributary of the
Susquehanna, Horvath told a conference of Chesapeake
Bay scientists in Baltimore yesterday.
"That gives zebra mussels now the potential to
colonize the entire freshwater system of the Susquehanna
River," Horvath told the gathering.
One Maryland expert said the zebra mussels are more
than 400 miles from the Chesapeake, and probably cannot
tolerate the saltier waters of the open bay.
"It is certainly something we should be concerned
about, because we don't want to risk the efforts
we've made in restoring the Chesapeake Bay,"
said Frank Dawson of the Maryland
Department of Natural Resources. "We're
still at a stage where we can control it.
"Unfortunately, our ability to control it may
not be as great as we would like," said Dawson,
who heads a scientific committee advising the bay restoration
program.
The scientists at the two-day Baltimore conference
are brainstorming ways to control half a dozen different
kinds of non-native plants and animals that have invaded
the region and are crowding out native wildlife.
Dawson said the advisory committee learned about the
infestation in the upstate New York reservoir last year,
and will work with Madison County officials during the
summer on a control plan.
"We need to take action right now to confine
them to that one reservoir," Horvath said.
The mussel infestations sometimes become so thick
that they radically change conditions in rivers and
lakes. In the Hudson River, dense beds of mussels filter
so much algae that the water is becoming clearer, Horvath
said.
However, a dense zebra mussel population in the Susquehanna
might harm efforts to restore shad runs and might allow
more nutrients to reach the bay, Horvath said. Nutrient
pollution is considered the bay's biggest problem,
causing a cascade of harmful effects on living things.
In Australia, wildlife managers have used chemicals
that kill mollusks to get rid of zebra mussels in small
bodies of water, Horvath said. The larvae can also be
killed by draining the areas where they live, but it
takes several days of drying to kill the adults, he
said.
