Wish You Weren’t Here

Quagga mussels — an extraordinarily prolific and costly invasive species — jump from the Midwest to Lake Mead. Dealing with them will be anything but a vacation.


  • Quagga mussel found in Lake Mead


  • Mussels encrust a crayfish


  • Wen Baldwin scrapes quagga mussel samples off the bottom of a boat-lift flotation tank at Lake Mead



On a summer day in 1988, in a shallow, heart-shaped lake near Detroit, two Canadian university students found the future. While searching for native mussels to use in a research project, the students fished up a rock, and on that rock was an unfamiliar striped mussel, no larger than a fingernail.

“We had no idea what it was, except that it was something new and very strange,” recalls biologist Paul Hebert, who supervised the project. “So I took a picture of it. I figured it’d be the last and only one I’d ever see.”

Experts soon identified the specimens from Lake St. Clair as zebra mussels, a species native to the rivers around the Black and Caspian seas. In a matter of months, the diminutive mussels had conquered the lake, coating hard surfaces with solid layers of sharp shells. They even encrusted the lake’s large native mussels, eventually killing them all. “The poor things starved to death,” says Hebert.

The zebra mussels hitched rides in boats, bait buckets and river currents, and within five years, they had established themselves in the five Great Lakes and in seven major rivers, including the Mississippi, Tennessee, Hudson and Ohio. Their ecological and economic misdeeds were soon infamous: Zebra mussels can rip apart native food webs, clog water intakes with tons of shells and mussel meat, foster the growth of noxious algae, and turn sugar-sand beaches into treacherous, stinking expanses of jagged shells.

Three years after Hebert snapped his photograph, scientists discovered another species of invasive mussel in Great Lakes, a close relative of the notorious zebra. The quagga mussel, named after an extinct zebra (“It was a jovial moment in the lab,” remembers researcher Ellen Marsden), soon proved more than a match for its predecessor. In the Great Lakes, many areas once dominated by the zebra now face quagga rule.

Biologists sometimes compare the movement of invasive species to a series of hubs and spokes. Successful invaders radiate outward until, through feats of endurance or gifts of luck, they leap into new territory, establishing new hubs — and soon, new spokes.

The quagga mussel made its first major leap in the late 1980s, when scientists believe it stowed away on a Black Sea ship and traveled nonstop to North America. Within the last two or three years — no one knows exactly when — the quagga leapt again. This time, the pioneers might have taken refuge in a persistent puddle on a fishing boat, or inside a rubber boot. They rode the freeways across hostile territory, surviving the plains and deserts. Finally, they found a new home in Lake Mead, the Colorado River reservoir just east of Las Vegas.

The mussels settled deep beneath the surface of the reservoir, and did what they do best: They multiplied, quickly and quietly. Lake Mead staff estimate that by the time they were discovered, on Jan. 6, 2007, they numbered in the millions.


Nearly eight years of drought in the Southwest have reduced Lake Mead to its lowest level in more than 40 years, and the reservoir’s exposed, dusty shoreline gives the Las Vegas Boat Harbor a makeshift air. But even on this late January weekend, the harbor is busy, and its gently bobbing docks are packed with boats of every description and provenance.

Wen Baldwin retired, more or less, to the Lake Mead area from Colorado 18 years ago, and he’s treated as a local here at the harbor; at its café, he greets the waitress and his fellow customers with cheerful teasing — despite his despondence over recent events.

“I feel like I’ve been hit by a stick by this thing,” he says, shaking his head over a cup of coffee. Baldwin led the crusade to keep invasive mussels out of the Lake Mead National Recreation Area, and it’s clearly no fun to be routed by bivalves. “They snuck right in underneath me,” he says, in a tone salted with genuine anger.

Baldwin first learned of zebra mussels about five years ago, when he heard an ecologist from Glen Canyon National Recreation Area — which encompasses Lake Powell, the next reservoir upstream from Lake Mead — speak about the likelihood of invasive mussel introduction in the Colorado River. “Whoa, it really got my attention,” Baldwin says. “Lake Mead was right in line. I could just visualize … well, I could just visualize it all happening here.”

In their native neighborhoods around the Black Sea, zebra and quagga mussels — both members of the genus Dreissena — are reined in by natural competitors and predators. But in the early 1800s, new canal systems allowed zebra mussels to invade Western Europe, where they became a widespread pest. Quaggas — which can tolerate deeper depths, cooler temperatures, and softer surfaces than the zebras and are generally a few hairbreadths bigger, averaging about the size of a pinto bean — seem to spread more slowly than their cousin mussels. But the quaggas have also made their way upstream from their native range.

Back in 1893, nearly a century before the zebra mussel crossed the Atlantic, English naturalist Harry Kew called Dreissena “one of the most successful molluscan colonists in the world.” Little did he know how right he was.

The problems caused by zebra and quagga mussels are intricate and far-flung, but they all start with sex: Though some adult zebra and quagga mussels are as small as grains of rice, each female can produce a million eggs each year. Each mussel that survives to maturity can filter a liter or more of water every day, taking in algae and other edible particles and spewing out water clear enough to use in a swimming pool.

This talent for purification sounds positive; it’s anything but. The particulates the mussels strain from their environment feed an array of aquatic invertebrates, which in turn feed fish, which in turn … you get the idea. Zebra and quagga mussels, by dint of their huge numbers and impressive industry, can disrupt food webs and, therefore, entire ecosystems.

Mar 06, 2007 12:43 PM

I don't want to sound uninformed, but can or do people eat these mussles? I know they are tiny, but I thought maybe if they were edible they could be collected for consumption. I doubt that would have any effect on their population, but would any little bit help? This could turn a profit for the removal of these invasive species. Thanks for your time and the great article! Eva Seifert-Aragon

Mar 08, 2007 11:11 AM

If food, then motivation to spread to other places. Why should one have to drive there to get the delicacy? 

Mar 08, 2007 11:16 AM

You sound uninformed.

Mar 12, 2007 02:46 PM


it's a good question. Here's what the USGS says about the
edibility of zebra mussels. It's safe to assume this applies to quaggas as well. -- Michelle Nijhuis

Are zebra mussels edible?
Most clams and mussels are edible, but that does not mean they taste good! Many species and fish and ducks eat zebra mussels, so they are not harmful in that sense. Zebra mussels are so small and do not have much in the way of "meat" inside them, you would have to be pretty hungry to
want to eat them.  However, because they are filter feeders, they can
accumulate pollutants in their tissues that may not be healthy for
people to consume. You should contact local public health officials to
learn whether it is safe to eat mussels or fish from a specific
waterbody. Therefore to be safe, it is not recommend they be eaten by

Apr 09, 2007 11:29 AM

Excellent article, as we have come to expect from Ms. Nijhuis. Invasive species are indeed a major problem in western states, with significant impact on habitat value and ecosystem services, and they rarely get such thorough coverage. Too often their spread is not observed until it’s too late to control them. The Saharan mustard marching across the Mojave Desert in recent years is but one example.

One of the silver linings of invasive species lies in the coalitions that have arisen in order to address them. Invasive plants in particular have brought diverse stakeholders together at the local level, often to form Cooperative Weed Management Areas (CWMAs). Since weeds don’t stop at fences, management requires involvement from many public and private landowners if it’s to have a chance of success.

Last year, the California Legislature was overwhelmed with letters from local groups, both agricultural and environmental, supporting funding for the state’s network of CWMAs. The program was granted $1.5 million, and this year groups are seeking an additional $1 million in the state budget. 

These local stakeholder groups took hold in the west, with all its public lands, but they are beginning to form in eastern states as well. This is resulting in further partnership, as groups nationwide look to influence federal policy. Organizations like ours hope that we can work quickly enough to stem the tide. Keep up the great coverage!

Doug Johnson, Executive Director

California Invasive Plant Council



Apr 10, 2007 11:11 AM

You can't eat the mussles, Even fully cooked. The water in lake meed has gas and harmfull oil. They are known to cause cancer. zebra mussles have this and things that are related to the zebra mussle. Any other mussle is okay at your market or food stores. 


Aug 06, 2007 04:54 PM

I would like to contact or be contacted by one or more of the biologists who are working on the eradication processes for one or both of these mussel species.

What are the initial steps to developing an eradication program for any given lake or water body? I know you mentioned that people are doing it but EXACTLY HOW are they doing it? How would one set up such a program at a specific lake in a new state where potential invasion is likely to occur? For example, Utah has a lot of deep, sandy, silty-bottomed lakes that are likely candidates for either species to invade. If I was a biologist in Utah, how would I develop an eradication program at specific lakes, such as the Flaming Gorge Recreation Area, that attracts hundreds of out of state boaters each year?

Can you please provide me with a list of names, phone numbers, and/ or email addresses of these people and/or organizations. Thank you.


Arnold Bradley, wildlife biologist, oregon

Jan 15, 2008 06:47 PM

An apparently successful effort to eradicate zebra mussels has been undertaken in a Virginia pond (see http://www.dgif.virginia.gov/zebramussels).

Bob Vadas, Jr., aquatic ecologist, Washington state


May 19, 2008 11:22 AM

ALL the boats in Lake Mead now have Quaggas all over the bottom.  Additionally, as you walk the shore line, quaggas cover ALL the rocks.  This is a HUGE problem that the National Park Service and the marinas, Las Vegas Boat Harbour and Lake Mead Marina both, are NOT addressing.  Oh, yea, the hauled in and out on a daily basis boats MAY get checked.  Kind of like closing the barn door after the cows are out now.

 But those of us that have boats that need CRANES to get them OUT of the water.  Forget about it.  The NPS has allowed marina vendors to be more interested in SELLING boats than taking CARE of the boat customers they already have.  There are NO cleaning stations for boats already IN the water; and the NPS marina vendors do NOT provide equipment to pull boats out of the water like marinas do in California and elsewhere.

 My tax dollars go to fund the National Park Service and all they do is build ramps for boats to come in from out of state.  Those people always have first choice of my tax dollar.  They buy their gas away from the marina, their beer is bought away from the marina, yet the NPS LOVES to support them.  Meanwhile, I pay over $5000 to keep my boat in the water and the NPS and the Marnia basically says, 'screw you' as a slipped owner.

I'm out of there after 10 years as soon as I can sell my boat.

chuck dunn
chuck dunn
May 28, 2013 05:07 PM