Alien invasion

My time as a government agent, searching for invasive species

Quagga Mussels on a rope.

Quagga Mussels on a rope.

photo/u.s. forest service

America is being invaded by aliens!

I’m not talking about foreign children crossing our southern border or malevolent beings from outer space. This is an invasion of tiny plants and animals from around the world that threaten our waterways and even our way of life.

I should know. I was a boat inspector in the front lines of the war against aquatic invasive species.

I saw the job posting last winter as I was considering what to do for the summer. The idea of hanging out on a boat ramp by a mountain lake was very appealing. I applied for and got a job with the Truckee Regional Aquatic Invasive Species Prevention Program—TRAISPP.

TRAISPP covers several reservoirs in the Truckee River Watershed, including Boca, Prosser and Stampede—water bodies popular with boaters wanting to avoid the hassle and expense of launching at Lake Tahoe.

Last year, the program was voluntary for boaters, so being a boat inspector was more about education than enforcement. We would normally be on station at first light to ensure thorough screening of all vessels before they launched. Only a few hardy fishermen would already be afloat.

Mornings can be quite cold until the lake fog burns off, and the boaters begin to arrive. Until then, deer, eagles and the occasional hot air balloon rule the dawn.

When the boaters arrived, I would direct them to a coned-off area and hand them a clip board with a screening application for them to fill out. While they were completing it, I would ask them a few casual questions to determine if their boats required an actual inspection, decontamination or even the extreme measure of quarantine.

Most often a screening application was all that was needed, so I would explain about aquatic invasive species and how to guard against them. At that point, I would issue the vessel a sticker for the season, good throughout the watershed and at Donner Lake, which has its own inspectors.

During training, a lot of emphasis was placed on dealing with difficult boaters, but it is my experience that most boaters were at least patient with the process, and many expressed sincere gratitude that we were there to protect their water.

In hundreds of encounters, I only had one negative experience and that was with a boater who irrationally thought the information we were collecting would be used by the government to track his movements.

Alien Origin

Whatever you may think about the merits of globalization, one thing is certain: All that global trade is helping transport foreign plants and animals to places where they don't belong.

Quagga mussels are one of the greatest threats to North American waters. They are no threat to their native Ukrainian lakes and rivers, thanks to natural predators and other factors, but having no such restraints here, they are free to multiply without constraint.

Scientists believe quaggas made their way to North America in the ballast tanks of ocean-going ships headed for ports in the Great Lakes. Quaggas were first spotted in Lake Erie in 1989.

Quagga mussels are prolific breeders. A single mature female is capable of producing up to 1 million eggs a year. Within a few days of fertilization, microscopic larvae called veligers emerge. These are free-floating creatures that quickly develop shells while looking for a hard surface to attach themselves to. This period can last up to four weeks and, although 99 percent of veligers perish before they become established, there are plenty of survivors.

Where quaggas become established, they quickly ruin the ecosystem. The mussels are coin-sized bivalve filter feeders. Each one can filter one liter of water a day, stripping it of the plankton that sustains fish and native mussels.

Since the veligers will attach to any hard surface, they can clog the filters and screens of power and water treatment plants, costing millions of dollars to remove them. They also foul marinas, boat engines and beaches. They only live for three to five years, so some beaches on the Great Lakes have drifts of the smelly sharp shells several feet thick in some places.

Since they were first discovered, quaggas have spread rapidly around the Great Lakes and nearby rivers and now infest many watersheds in the East. By 2007, they had infested Lake Mead and parts of the Colorado River. This dramatic expansion is the result of human activities. That’s where I come in.

Quagga mussels are surprisingly resilient. They can live out of water for as long as 30 days under the right conditions and even longer where moisture is present. And because the veligers are microscopic free-floaters, a vessel can be contaminated with quaggas without the boat owner’s knowledge.

Quaggas have not been found in the Truckee River watershed or Lake Tahoe yet. Boat inspection programs are particularly targeted at keeping it that way.

One of my first questions during screening was to ask where the boat had launched in the last 30 days. If the answer was Lake Mead or another water body thought to be infested such as Lahontan Reservoir, I would not issue a sticker until a complete inspection or decontamination was carried out.

This does not apply to non-motorized vessels such as kayaks or paddle boards, but all other vessels including sailboats would need to be closely inspected. The first step would be to board the vessel and look for standing water or mud in lockers, bilges and boat systems.

Next would be an examination of the hull, screw and trailer. Veligers may be invisible, but they can be felt, having a texture like coarse sandpaper.

Any time any evidence of infestation is found, decontamination is necessary. Wakeboard boats with ballast tanks are always decontaminated if they have been to another water body.

My program was voluntary last year, so any boater could launch if they wanted regardless of the risk to the environment. However, most boaters complied and had their boats decontaminated. This involved taking the vessel to a decontamination station at Northstar or Alpine Meadows ski areas and paying a fee for the service. Decontamination is achieved by flushing all internal systems and pressure washing the exterior with 140 degree water for 30 seconds.

Alternatively, an obviously infested boat could be impounded and quarantined even under the voluntary program. I know of no instance when that was required last summer, though.

The mantra of the boat inspection program is for boaters to arrive clean, drained and dry: bilge plug out, hull wiped off and various lockers and water toys dried out. Observing this mantra can often mean the difference between a quick inspection and a full decontamination. At mandatory inspection water bodies such as Lake Tahoe, that can mean the difference between waiting in line for up to an hour and being on the water.

Aliens in America

Invasive species prevention programs can be quite expensive. The program at Lake Tahoe alone costs nearly $1.5 million a year, but according to a U.S. Army Corps of Engineers study, should quaggas become established in the Tahoe Basin, the tourism industry could lose $22 million.

However, the program is not without its critics. Truckee was poised to approve mandatory inspections last summer but decided to postpone action until more scientific studies could be conducted.

One of the program’s most vocal critics is long-time Donner Lake resident and retired civil engineer Steve Urie, who contends that invasive mussels cannot successfully colonize Tahoe or Donner lakes because their calcium levels are far too low to sustain the animals.

He points out that only one local study supports the belief that quaggas can survive in these waters. In 2008, the Environmental Protection Agency gave Dr. Sudeep Chandra, a University of Nevada, Reno scientist, a $20,000 grant to conduct a limited experiment to test quaggas’ survivability in Lake Tahoe.

Chandra’s team transplanted eight adult quaggas from Lake Mead to his Reno lab where they were placed in water taken from the Tahoe Keys. One mussel died and the rest were losing body weight when the experiment concluded, but Chandra wrote that it is possible for adult quaggas to live and reproduce in Lake Tahoe. He suggested that mandatory boat inspections are prudent.

According to Urie, the study was inconclusive at best. He believes it a waste of scarce financial resources for the town to fund the inspection program based on such weak evidence.

Quagga Mussels may be small individually, but as a species, they are the greatest threat to North American waters after humans.

PHOTO/U.S. Fish & Wildlife service

Another criticism of the program in Truckee is how permeable it has been. For example, inspections at Donner Lake take place only at the public boat ramp. Two other ramps are unmonitored. Boaters at any of the reservoirs can and do launch from the shore instead of the boat ramps.

That wasn’t much of a problem when the program was voluntary because of its educational component. But, this year, the program is mandatory with decontamination fees expected to pay half of its expense at Donner Lake.

In response to critics, program officials point out that their efforts include prevention of the spread of all aquatic invasive species.

Even though quagga mussels are the poster children of aquatic invasive species, they are not the only ones. Zebra mussels pose another threat similar to that of quaggas. There are also Asian clams, New Zealand mudsnails and Eurasian watermilfoil to contend with. The latter two have already found their way into Lake Tahoe and Donner Lake and are making their way down the Truckee River into the Reno area.

Eurasian watermilfoil was first spotted years ago in the Tahoe Keys where it probably arrived on the hull of a boat. It spread rapidly and officials brought in threshers to chop the stuff up. All that was accomplished was to spread it more widely.

New Zealand mudsnails are tiny enough to hide in a clump of mud and are probably spread by fishermen who may not clean their gear well enough.

The main educational duty of a boat inspector is to acquaint the public with these various threats and inform them about ways to identify and destroy them before they are spread to other water bodies.

Aliens of the Deep

Thanks to the ongoing drought, many nearby water bodies are drying up and that means more boats heading to the deeper waters of Alpine lakes such as Tahoe and Donner. Tahoe boat inspectors saw a 17 percent increase over the Fourth of July weekend, and the season was still young.

Ironically, despite increased demand, funding is going to decrease dramatically. About half of the Tahoe boat inspection program’s $1.5 million comes from a federal program that will expire next year.

According to Dennis Zabaglo, AIS Program Coordinator for the Tahoe Regional Planning Agency, cuts are being enacted this year in anticipation of next year’s shortfall. The inspection station at Homewood has been closed, hours of operation at the other stations have been cut and fees have been increased.

“We are actively pursuing public-private partnerships to make up for the loss of funding,” Zabaglo says, “but we’re also seeing a lot of buy-in from the boating public and that makes our job much easier.”

Zabaglo estimates his program, jointly operated with the Tahoe Regional Conservation District, has intercepted more than 20 infested boats so far this season.

By contrast, the Truckee watershed program is seeing an increase in funding, according to TRAISPP director Teresa Crimmens. This program is primarily funded by grants from local governments, environmental groups and the Truckee Meadows Water Authority. It is also part of the Tahoe Regional Conservation District.

Last summer, TRAISPP employed a half-dozen boat inspectors. This year, there is only one part-time inspector even though boat inspections are now mandatory in Nevada and Sierra counties.

Crimmens says the program is moving toward encouraging self-inspection programs through increased use of informational rack cards and signage.

“There are lots of places to launch, any time of the day or night and we can’t police them all,” Crimmens says. “That’s why we’re moving toward mandatory self inspections.”

The new approach is modeled after a similar program in Utah where boaters must fill out and display a questionnaire that mirrors what information would be asked by a boat inspector.

Kim Gorman, program director for the Tahoe Regional Conservation District, says her organization never intended to “own” the inspection programs in Nevada and Sierra counties, just get them started. It is now up to the counties to develop their own programs.

Alien Nation

Invasive species are not just aquatic, and they are occurring everywhere. Noxious weeds are endangering the Nevada desert even as bark beetles are devastating Sierra forests. Alien snakes, bugs and birds are upsetting the ecological balance in other parts of North America even as North American plants and animals endanger other parts of the world. Some scientists classify cats, wild horses and even humans as invasive species.

Although prevention is the most effective policy to date, scientists are looking into other ways to address this global problem. One approach is to simply do nothing. For example, in some lakes long infested with quaggas the water is cleaner now than before infestation. That’s because the mussels effectively ate everything edible and then starved to death, but that took many years.

Scientists have also considered introducing alien fish that eat quaggas. But, aside from unintended consequences brought about by the fish themselves, there was also the fear that toxins collected by the mussels would work their way up through the food chain.

Zabaglo says the TRPA has been experimenting with plastic sheets to kill New Zealand mudsnails and manual removal of Eurasian watermilfoil in Emerald Bay. He says the program is highly successful, but critics say the plastic sheets also kill native species.

Another alternative is to eat invasive species ourselves. Farming crayfish in Lake Tahoe is one example of turning an invasive species into food. Invasive Tiger Prawns are a big problem in Louisiana but are now a popular delicacy there. Even quaggas can be eaten by humans, but the toxins they contain are a problem.

A radical new approach was unveiled in a paper published in Science magazine earlier this month. According to Harvard University genetic engineer Kevin Esvelt, one of the paper’s authors, gene drive technology could potentially cause local extinction of invasive species and restore the original ecosystem.

The idea is to identify a genetic alteration that could reduce pesticide resistance, hinder a population’s ability to reproduce or have some other desirable effect on an invasive species.

Scientists could then insert that alteration into the genome of an invasive species, but there is no guarantee that it will take because there is only a 50-50 chance the altered gene would propagate.

Esvelt says gene drives make it much more likely the altered gene will be dominant thanks to new technology that gives genetic engineers the ability to target very specific elements in the genome.

The new tool can be applied in a variety of ways, says Esvelt. One scenario is to alter a sex-determining gene to increase the likelihood that progeny are male. Another could be knocking out genes that are important for fertility.

However, scientists have yet to consider possible downsides such as altered genes further altering into something else once introduced or spreading to similar but non-targeted species.

Even Esvelt urges scientists to make sure the technology is being used responsibly, but with invasive species causing $120 billion in economic damage in the United States alone, there are plenty of incentives to push forward.

In another recent development, researchers in the United Kingdom and Germany have developed a model to predict the likelihood of a bio invasion at locations around the world.

They studied two years worth of shipping data involving millions of voyages to map which areas are most at risk from aquatic invasive species. They found that the animals are less likely to survive long voyages than previously thought, but the proliferation of shorter trips makes some areas more prone to successful invasions.

These include the Suez and Panama canals as well as major ports such as Hong Kong and Singapore.

Their hope is to spur the shipping industry to spending money on ways to purify their ballasts before animals escape into local water. Shipping companies are reluctant to take such steps, but the model could give local port authorities more power to enact stricter rules in the future.

In the meantime, boaters will have to be the ones who arrive clean, drained and dry. And if they don’t, hopefully, there will be a boat inspector as a last resort against the invading aliens.