Zebra mussels found in the Trinity River
Source: NBC DFW
University of North Texas biologists say they
have found zebra mussels in the Trinity River in Denton County,
less than a year after the invasive species was discovered in Lake
The first sample was found during a research
trip by several biology students. Senior Bethany Hambrick made the
find under a rock about a mile south of Lake Ray Roberts.
"I was looking for fossils and fresh water
mussel cells and picked up a rock and I knew that the morphology
was not anything that I'd seen before," she said. "I had a
suspicion it was a zebra mussel, and that was sadly confirmed."
Large colonies of the species were discovered in
Lake Ray Roberts last summer and at Lake Texoma about three years
earlier, but this is the first time any have been found in a Texas
"I think it's inevitable that they'll continue
downstream," said James Kennedy, a UNT biology professor who's
closely monitoring the zebra mussel situation for the state. "You
can treat zebra mussels in confined regions, but to go out and try
to treat and manage a river system like the Trinity River watershed
is going to be practically impossible."
From a biological standpoint, zebra mussels are
dangerous to Texas' waters because they are too efficient at
cleaning and filtering, he said.
"They pull particles, algae, microscopic plants
out of the water, particularly the organic matter out of the water,
which is the basis of the food chain for fresh water ecosystems,"
The bigger problem with their presence in the
Trinity River is that it's such a major source of water for the
area. The mussels clog water intake pipes, making it difficult to
move water to reservoirs.
They could potentially have a huge effect on the
cost of fresh water, Kennedy said.
"They have to be mechanically removed because
these mussel shells attach themselves very tightly to the pipes,"
They also harming boats and motors left in
infested waters, and the sharp edges of their shells can injure
swimmers and other animals in the water.
"It is a very severe situation," Hambrick
"We're basically at this point just cataloging
them. We put them into a database and we photograph them," grad
student Colleen VonEhr Evans said. "It gives us a better idea of
how quickly they're going downstream."
For now, UNT will continue to monitor the
waterway to track where the mussels move.
Officials with the Texas Parks and Wildlife
Department say the species can be spread from lake to lake by
boaters who don't properly clean their watercraft between
The department launched a public education
campaign last year to encourage lake users to clean, drain and dry
their boats, trailers and gear.
Kennedy said the invasive species originated in
the Balkans and was brought to the Americas more than 20 years ago,
likely attached to a ship in the Great Lakes.
They were first spotted stateside in Michigan
in 1988 and have since spread to 29 states and more than 600 lakes