This one is called the quagga mussel, a relative of the much-publicized - but ,as it turns out, somewhat wimpy - zebra mussel.
"The quagga mussel has been described as a zebra mussel on steroids," said Wayne Gustaveson, Lake Powell project leader for the Utah Division of Wildlife Resources. "As the manager of the fish in Lake Powell, I'm petrified that if we get them here, my fisheries would drastically decrease in quality and quantity."
Gustaveson has worried about a freshwater mussel invasion at Powell for more than a decade, but his fears increased a hundredfold when National Park Service officials confirmed the presence of quagga mussels at Lake Mead National Recreation Area in Nevada in early January.
Zebra mussels started their invasion of North America in the Great Lake region in the late 1980s via a transport ship. They have remained on the east side of the Continental Divide, but the quagga appears to be more resilient.
Quagga and zebra mussels have a negative impact on fish species because the rapidly reproducing freshwater mollusks filter tons and tons of plankton, the primary base in the food web of every fishery. The mussels' waste is also a threat because it steals oxygen from the water as it decomposes.
Further complicating the problem is the fact that they have no natural predators. Fish cannot eat them.
The invasion of freshwater mussels goes far beyond angling, though. Power companies have spent hundreds of millions of dollars trying to prevent the mollusks from blocking water intake pipes, usually to no avail. The high cost of cleaning and replacing intake pipes is passed on to the consumer. Boats, motors and docks also become covered by quagga and zebra mussels.
Houseboating at Lake Powell could also change forever if the mussels arrive.
"There won't be sandy beaches, just shells to cut your feet on," Gustaveson said. "There is not one good thing about them."
In 2000, federal, state and local officials started an education program at Powell after it was dubbed one of the most likely waters in the West to succumb to mussel invasion. Boaters were asked at entrance booths if their boat had been in the water east of the Continental Divide in the past seven days. If it had, the boat was sent to the marina for a hot-water wash.
Gustaveson says officials were washing six to eight boats a month before the quagga outbreak lower on the Colorado River at Mead. With boats coming from Mead on a regular basis, Gustaveson expects the washing will increase to somewhere between 500 and 1,000 boats a month.
Of course, it might already be too late.
"I've got somebody at the dock right now with an Aqua-Vu looking for them," Gustaveson said Tuesday.
* BRETT PRETTYMAN can be contacted at brettp@sltrib .com or at 801-257-8902. Send comments about this column to email@example.com.
You can help
Here are some steps you can take to avoid spreading exotic mussels.
* DRAIN THE WATER from your motor, live well and bilge on land before leaving a lake.
* FLUSH THE MOTOR and bilges with hot, soapy water or a 5 percent solution of bleach.
* COMPLETELY INSPECT your vessel and trailer, removing any visible mussels, but also feel for any rough or gritty spots on the hull.
* WASH THE HULL, equipment, bilge and any other exposed surface with hot, soapy water or use a 5 percent solution of household bleach.