Quagga and zebra mussels are the menace. Since the invasive species were found in Lake Mead National Recreation Area in January, surrounding recreation areas have been ramping up an attack to keep them from spreading to other areas and lakes, because the potential infestation of the non-native species would have devastating effects on the environment, native species and recreation wherever they are found — including Lake Powell.

The discovery of the quagga mussel at Lake Mead prompted Glen Canyon Recreation Area managers to have an aggressive public-education effort, says Kevin Schneider, GCRA spokesman. Schneider says when agencies found mussels in Lake Mead, Lake Mohave and Lake Havasu, they represented the invasion of the species for the first time west of the Rocky Mountains. The arrival of the zebra mussel in the West was anticipated for a long time, but the quagga mussel, which lives at deeper depths, appears to have been the initial invader. As of yet, neither type of mussel has been found in Lake Powell or the Grand Canyon. Whether it remains that way depends largely upon public vigilance, say private and public lake managers.

All the way from Ukraine

Zebra and quagga mussels are related mollusks that are indigenous to the Dneiper River drainage of Ukraine. First discovered in the Bug River in 1890, the mussels spread relatively quickly throughout Eurasia, mostly because of the extensive construction of canal systems. By 1989, scientists found the first quagga mussel in the Great Lakes, specifically near Port Colborne, Lake Erie. Since then, their prevalence in the eastern part of the United States has created an ongoing battle for scientists working to study the biology, ecology and physiology of the mussels and for recreation managers who desperately try to prevent the spreading to untouched areas.

Mussels are prolific breeders. Scientists with the United States Geological Survey believe that a fully mature female is capable of producing as many as 1 million eggs per season. That sets the stage for thousands of these mussels to do substantial damage.

Though the two types of mussels are of the same genus and have similar appearances, they are easily distinguishable. The shell is the key distinction, says Myriah Richerson with the USGS. Zebra mussels have a more definite angel of the front and back sides. The angels are sharper and appear somewhat flatter, almost triangular. Quagga mussels, however, are more rounded shell and a convex underside when you lay them flat.

The mussels spread by attaching themselves to boats. That has earned the quaggas and zebras the moniker of “aquatic hitchhikers.” When infected boats go into mussel-free water, they immediately contaminate that water. Then, it becomes a game of eradication, and because they thrive on water, all bets are off when trying to remove them from lakes. Schneider says the hot, dry weather in the desert West helps slow the spread of the mussels, because mussels can’t live out of the water for long periods of time.

Zebra mussels are biofoulers and attach to hard surfaces. In some cases, they form a mat that may be as much as 18 inches thick. Even one thick mat can contain hundreds of thousands of individual mussels. According to a report from the GCRA, in western Lake Erie, more than 700,000 mussels were discovered in one square meter.

Recreation managers anticipated the invasion in 1999 and this year immediately established boat-washing stations at various marinas on Lake Powell. The boat washes at Wahweap and Bull Frog marinas are operated and paid for by concessionaire proceeds. Schneider says those two marinas are the most heavily used on the lake. There also is a portable unit at Halls Crossing. There also is a washing station at Antelope Pointe Marina, which the private company paid for.

The washing stations are only part of the efforts the lake managers are making to help the public learn about and keep the threat at bay. There also is a constant stream of information on public and private Lake Powell Web sites. The GCRA also now requires boaters to have a certification verifying that their water craft are free of quagga and zebra mussels. The self-certification process, says Schneider, is quick and easy. Once certified, boaters have to carry the proof in their cars always.

Wayne Gustaveson, an expert angler at Lake Powell and who also maintains the popular Wayne’s Words Web site, says Utah has mailed quagga mussel notices to all registered boat owners in that state. California has done the same. Gustaveson says boats also are stopped at Lake Powell entry points so they can be inspected.

“I feel that 85 to 90 percent of users are now aware,” Gustaveson says. “We need to work hard to inform the other 15 percent, so there will be an ongoing effort to do that.”

Money matters

Schneider says it is difficult to quantify how much money is being spent on educating people about the mussels. Even without a hard number, though, he says it likely doesn’t compare to the amount of money it would cost if the mussels contaminate Lake Powell.

Quagga and zebra mussels dramatically alter a lake once they are in it. This includes disrupting the food chain for aquatic life and leading to the decline of fish species — in numbers, health and physical condition. Zebra mussels filter water for food and end up taking over the phytoplankton and microscopic nourishment that the fish in the lake and other mollusks and birds rely on to live. Also, the quagga mussels soak up more contaminants than naturally occur, so they become quite toxic. The potential damage is huge. “Fishing would be impacted as less stripers and smallmouth would be available to catch. The size of those fish caught would be smaller,” says Gustaveson.

The mussels also will foul boat docks and ramps, as well as beaches. Their razor-sharp shells cut hands and feet. Gustaveson says that if they are in Lake Powell, beaches could be ruined by “dead and dying sharp, smelly mussels and shells.” So there also would be an impact on recreation at the lake.

Boat owners also would face severe consequences. Mussels encrust boats and clog engines, making maintenance difficult and costly. Schneider says if mussels appear, boaters will spend much more time and money to take additional steps to keep their boats free from constant infection. “Everybody is far better off to spend the money now to beat the contamination,” he says.

Even drains and intake pipes will be affected, he adds. Many lakes’ intake pipes are designed to flush unnecessary species and other matter through them without the risk of clogging. But Schneider says that’s not the case at Lake Powell. Intake pipes are smaller and less forgiving. “Millions of dollars would be spent by the power generators to ensure their pipes stay open to deliver water,” Gustaveson points out.

Optimism exists

Schneider says controlling mussel infestations requires a multitude of approaches. No single approach can control them. Some aquatic predators could help, such as ducks or lake sturgeon, and even chemicals and mechanical scraping. But those methods work only to a point.

The National Park Service has hired divers for its water-quality program, asking them to be aware of mussel presence. The park service also regularly immerses PVC pipes in different points at Lake Powell to inspect them for mussels. Schneider says the last round of testing showed no presence of them.

Beyond ecological damage, mussel infestation has potential devastating effects to the economies that rely on Lake Powell. Schneider says the park received about $130 million in 2005 from recreation revenues, or visitor spending. Lake Powell’s existence creates just less than 3,000 jobs and reports as many as 3 million visitors annually. Mussels would no doubt affect those numbers, he explains. “I just don’t know how hard hit those numbers would be,” Schneider adds.

Still, Schneider is hopeful. He says the lake managers — public and private — have ample information and resources to help them address the potential problem. A variety of nonprofit organizations, including Web sites like Gustaveson’s and similar ones have hit the ground running in the West. They are actively spreading the news and using literature — some of which comes across like a Most Wanted criminal list — to prevent the actual spread of mussels. Depending on whom you talk to, 100 percent prevention is possible. Some think it’s an impending disaster. But Schneider doesn’t.

“I think it is possible to prevent it,” he says. “We are optimistic. And we look to Minnesota for optimism. They have done a lot of education. It is the land of 10,000 lakes and yet they have only three lakes that are infected.”

Amy Maestas is a contributing editor of Inside/Outside Southwest and a freelance writer in Durango, Colo. She dislikes all kinds of mussels.