Invasive mussels stopped by wary Texas worker

FORT WORTH, Texas – They have been nicknamed “aquatic cockroaches” for their ability to multiply and the difficulty in getting rid of them.

In the Great Lakes and along the Mississippi River basin, they have flourished and created new headaches.

In recent years they have made it to Texas’s doorstep with sightings in Arkansas, Oklahoma and Louisiana.

And if not for an alert Lake Texoma marina worker, invasive zebra mussels would have hitched a ride into Texas waters this fall.

The mussels, which have been labeled a “noxious species,” were tucked away in the motor and trim tabs on a boat that had just been shipped to Texas from Wisconsin.

“It wasn’t real obvious; they were covered in slime,” said Tim Ray, a service technician at Highport Marina on the Texas side of Lake Texoma who discovered the invasive mussels on Oct. 10. “But once you started looking more closely, there were probably a thousand of them on the boat,” Ray said.

The lake, about 60 miles north of Dallas, straddles the Texas-Oklahoma state line.

Texas Parks and Wildlife Department officials said the zebra mussels wouldn’t have been discovered if not for Ray’s sharp eye.

“The real hero here was Tim Ray,” said Bruce Hysmith, a parks and wildlife fisheries biologist. “He was on top of things and had read enough about zebra mussels to know what he was seeing.”

The tiny zebra-striped shellfish are generally 3 to 5 centimeters and can live four to five years.

The boat owner, who had just moved to Texas from Minnesota, was issued a warning but did not receive a citation because the boat was supposed to have been cleaned before it was shipped, said Capt. Scott Haney, a state game warden.

The boat will now undergo a decontamination process that will likely take a month.

The close call underscores how rapidly zebra mussels have expanded since being discovered in the United States in 1988.

Their larvae are believed to have arrived in the ballast water of a freighter from the Black Sea, according to the U.S. Geological Survey.

The mussel can attach itself to boats, dams, docks and other objects.

It has caused major problems in some parts of the United States by clogging municipal water lines and boat motors. It can also damage the aquatic food chain by eating small microorganisms that are integral to fish.

There have been instances of 10,000 zebra mussels attaching to a single native mussel in Lake St. Clair, the first body of water where they were found in the U.S.

In Lake St. Clair and the western basin of Lake Erie, native mussels have all but disappeared, according to the USGS. The agency also noted that the mussels have in effect reduced the diameter of some Michigan water treatment plant pipes by two-thirds. As a result, many treatment plants in the upper Midwest have had to retrofit their intake valves to prevent mussels from clogging their water systems.

The creatures’ razor-sharp shells can also turn swimming holes into no-swim zones.

Last summer they were discovered in the Tulsa, Okla., area, prompting concern about their spread to other Oklahoma lakes.