WICOMICO RIVER - On the wall of the nutria eradication team’s drab office at the Blackwater National Wildlife Refuge, there’s a large whiteboard with names and numbers on it. They’re bets for a long-running pool: How many nutria will the team find in the marshes of the Wicomico River?
“The people that guessed 90, 70, 120, they’ve already lost,” says Stephen Kendrot as he drives along a Wicomico County backroad.
It’s an overcast April afternoon with a long-awaited bit of warmth in the air. The nutria project leader is coming back from a site in Quantico, where four of his trappers are roaming the Wicomico River in jon boats. They’ve killed about 120 nutria there so far and found a few more this morning.
The river is the site of the final battle in the long-running quest to eradicate the beaver-like rodents (“nutria” means “otter” in Spanish) that have destroyed thousands of acres of the state’s wetlands over the past 40 years. It has taken longer than expected -- news articles profiled the waning fight in 2011 -- but finally, the state is almost free of the invasive rodents.
Led by Kendrot, the project, administered by the U.S. Fish and Wildlife Service and implemented by the U.S. Department of Agriculture Wildlife Services, has cleared marshes up and down the Delmarva Peninsula over the last 12 years. On the Wicomico River, Kendrot’s team is after the last surviving colony.
The critters feed on the roots and tubers of marsh plants, which cuts up the root mat, a fibrous layer that holds the marsh together. Water can then flush in and out with the tide, eroding the root mat. The marsh begins to sink. Eventually, the wetlands turn to ponds.
The open water has little value to fish and wildlife that rely on the wetlands, and it can’t support vegetation that could provide new habitats.
Additionally, marshes serve as filters that keep pollutants from draining to the bay and even trap some carbon dioxide, said Doug Myers, Maryland senior scientist at the Chesapeake Bay Foundation, one of the non-governmental organizations that supports the project.
Not only does marsh loss eliminate these benefits and destroy habitat and food sources, it also leaves the marsh more vulnerable to other factors, including sea level rise, saltwater intrusion, land subsidence and groundwater withdrawal, Kendrot said.
“A marsh without nutria is somewhat resilient to all these other factors, but with nutria it doesn’t stand a chance,” he said.
The wetlands in the Chesapeake region have experienced more marsh loss than most other wetlands around the world, Kendrot said, and a study in the 1990s proved that, even with other contributing factors, nutria were largely responsible.
The semi-aquatic critters (Kendrot describes them as “a 20-pound rat with a scaly tail and buck teeth”) were brought to the U.S. from South America in the 1940s for the fur trade. They have established colonies in states throughout the Southeast and Pacific Northwest. In Louisiana, the nutria population reached 20 million in 20 years, creating a problem that is now too large for eradication.
The race against nutria in Maryland has cost between $16 million and $17 million total to date; the project receives between $1.3 million and $1.5 million a year, federal money funneled through the Fish and Wildlife Service.
Coming into its 14th year, the nutria project has received substantial attention in the U.S. and around the world. Kendrot, who’s hosted delegations from Israel, China and South Korea, among others, said visitors come from all over to learn about the team’s techniques in the hopes of implementing similar programs in their areas.
Research for a nutria project began in the mid-1990s, the program was launched in 2000, and eradication began as an experimental pilot program in 2002. By 2010, the team was confident it could actually wipe the species from the Maryland landscape.
Their strategy combines more traditional population management techniques with geographic information systems, GPS and mapping technology that Kendrot says sets the program apart. They have pioneered various detection techniques that help them track, trap and kill the nutria, and collected a huge amount of data on the creatures. Catches go back to the shop, where specialists mine the carcasses for information like age, sex and pregnancies.
Detecting the nutria is the biggest challenge, Kendrot said -- to figure out both where they are and where they aren’t. The latter is key to eventually achieving eradication.
“How do you go about proving nutria don’t exist? It’s kind of like proving Bigfoot doesn’t exist,” Kendrot said.
During the first year of trapping on the peninsula, the team caught 5,000 nutria at the Blackwater Wildlife Refuge and in adjacent private lands, Kendrot said. Today, it’s been two and a half years since a “nute” was spotted at the refuge.
The trappers have moved down the coast over the years to cover Fishing Bay, the Nanticoke River, southern Dorchester County, Ellis Bay, Monie Bay, Deal Island and the Choptank River.
To date, the team has killed more than 13,000 nutria in Maryland, deeming 216,201 acres of the Delmarva Peninsula nutria-free with 11,357 acres to go. (Half of the peninsula’s 500,000 acres was clear of nutria from the start.)
Delmarva, which is bordered by the Chesapeake Bay, is “ground zero” for nutria, where they were first introduced in Maryland. Nine of its major watersheds were infested with nutria at the start of the project, Kendrot said.
Combing the dense marshes for the elusive animals is a big job for a 10-man staff, and their observations can only provide snapshots, so the team must be vigilant, Kendrot said. After they think they’ve eradicated nutria in an area, they begin a verification and monitoring stage to make sure the critters don’t return.
The team estimates that it can catch about 95 percent of nutria in a given area within four weeks, but the last five percent can take just as long as the first 95.
“When it gets down to the last, it gets more interesting. More challenging,” said Richard Elzey, Sr., who has been a wildlife specialist with the project since 2002.
There are probably between 200 and 500 nutria remaining in the area, Kendrot said. They don’t expect to catch the last one, but rather to get the population so low that the remaining few die off.
The team will finish initial trapping by the end of 2014, but they won’t declare the state officially eradicated until 2017, after a period of surveillance to make sure new nutes don’t sneak in.
But the team’s true focus is on what happens after they leave the marsh.
“You can’t measure the efficacy of eradication by how many critters you kill. It’s what you leave behind that determines your success,” Kendrot said.
In some areas, like two sites on the Choptank River and in Somerset County, the marsh recovered completely after the USDA team removed the nutria there, Kendrot said. But there are other places that can never fully recover.
At Blackwater Refuge, the last nutria was caught in December 2011. But the marsh, which was once so dense you could walk across it at low tide, is filled with water.
“Much of this marsh was lost by the 70s and 80s, so a lot of people that visit today don’t even make the connection that this isn’t a healthy ecosystem, it’s not what it should be (or) certainly what it used to be. They just see a beautiful lake with some geese swimming out in it,” Kendrot said.
In 2003, the Blackwater Refuge partnered with the Army Corps of Engineers and Baltimore’s National Aquarium, among others, to restore parts of the refuge, but it cost $300,000 for just six acres. There isn’t funding to restore the more than 5,000 acres of marsh that have been converted to open water, Kendrot said.
Elzey, who grew up near Blackwater and has watched its marshes disappear over the course of his life, said he wished the project had started in the 1970s. He trapped nutria when they were first introduced on the Delmarva Peninsula.
“I remember when it was just a creek running through. All marsh. All marsh, and I tracked it all,” he said.
Some animal cruelty groups oppose the eradication of invasive species, but there has been relatively little opposition to the nutria project compared to similar programs, Kendrot said.
Though the environment is more important than the nutria, the Bay Foundation’s Myers said he wished the dead animals didn’t go to waste.
“There are lots of good uses for nutria, including the meat and the furs and we would probably prefer that that happen as opposed to just allowing them to go, because we think they’re cute and cuddly,” Myers said.
But there is no market for nutria fur or meat, Kendrot said, as places like Louisiana learned when they tried to start up a commercial nutria meat market (though there are plenty of recipes available online for curious hunters). Production costs would be high and Wildlife Services couldn’t ensure the safety of the meat for human consumption, anyway, he said.
Kendrot said the line of work is controversial but justified when considered in an environmental context.
“It’s a hard leap for some people to make. How can killing animals be considered conservation? But the project isn’t to kill nutria. It’s to save the marsh,” Kendrot said.
On the Wicomico River, Elzey and the rest of the team have been trapping for a month. They’re in what they call the knockdown phase: searching for nutes and tracks, looking for catches and setting new traps daily.
The wildlife specialists spend eight to 10 hours a day on the water. In the dead of winter, this sometimes means working with wind howling across a frozen marsh. In the summer, mosquitoes and gnats buzz about in the humid air. Dead nutria often ride with them in the bottom of the boat while the men finish checking the traps.
“If you like doin’ it, then it don’t bother you,” Elzey said. “You’ve gotta love to do it to do the job.”
It takes a certain kind of person to do the project, Kendrot said. Though he’s an avid hunter, he said he has mixed feelings on whether or not killing the animals ever bothers him, saying he doesn’t “like to demonize the critter.”
He names admiration and gratitude as emotions that characterize his relationship with nutes, and he clearly believes in the work he’s doing.
“You know, a lot of people spend their life trying to do something that has a real tangible outcome and obvious impact on the environment or whatever, leave a legacy, and never get that opportunity, and this one’s been dropped in my lap so to speak, and it’s, you know -- if we’re successful we’ll have achieved something pretty remarkable,” he said.