Partnership Tackles Removal of Invasive, Marsh-eating Rodent from Delmarva Peninsula

On Maryland’s Eastern Shore, pollution from development and agriculture are much-debated issues affecting the Chesapeake Bay's health. But one of the region's most destructive forces is unseen by many: a large, beaver-like rodent that digs out and feeds on the roots of marsh grasses.

Nutria are an invasive species that live in the Delmarva Peninsula's marshes and wetlands. Since their introduction in the 1940s, nutria have eaten through thousands of acres of marshland on the Eastern Shore. Blackwater National Wildlife Refuge in Dorchester County has been especially hard-hit: nutria have destroyed more than half of the marshes there -- nearly 7,000 acres.

Marshes and wetlands are important because they protect clean water by filtering out pollutants and reducing shoreline erosion. They also provide opportunities for outdoor nature activities such as paddling, hiking, hunting and bird-watching.

Additionally, wetland destruction by nutria costs Maryland’s economy $4 million per year in lost environmental services from the degradation of farmland, property, water quality, commercial fisheries and outdoor activities. Recent reports estimate that figure will increase to $30 million per year by 2050 if nutria are left unchecked.

To combat nutria’s destruction of valuable marshland, a group of federal, state and local organizations has come together to eradicate the invasive rodent from the Eastern Shore.

The Maryland Nutria Project began in the late 1990s as the Maryland Nutria Project Partnership, a group of 22 organizations that joined together to investigate the potential to eliminate nutria from Eastern Shore marshes. In 2000, the U.S. Fish and Wildlife Service received federal funding to develop a strategy to eradicate nutria in Maryland.

Today, the Maryland Nutria Project is one of a small handful of highly successful invasive species programs in the United States. Since its work began in 2002, the Project has removed nutria from almost 150,000 acres of wetlands in Caroline, Dorchester, Somerset, Talbot and Wicomico counties.

The Maryland Nutria Project’s trapping efforts were originally concentrated in a 95,000-acre “nutria eradication zone,” which included Blackwater, the state-owned Fishing Bay Wildlife Management Area, the privately owned Tudor Farms, and other nearby private lands.

“Except for monitoring activities, the Project is finished in the nutria eradication zone,” said Dan Murphy, program supervisor with the U.S. Fish and Wildlife Service Chesapeake Bay Field Office. “We are continuing to expand out of Dorchester County into nutria-infested marshes in Caroline, Somerset, Talbot and Wicomico counties.

Marshes have shown a remarkable ability to recover once nutria are removed from an area. But without a continued effort to eradicate them, nutria will re-infest and once again destroy wetlands. The Project must expand its efforts into the remaining five southern Maryland Eastern Shore counties and the Delaware and Virginia portions of Delmarva -- a total of more than 400,000 acres of wetlands.

“The challenge ahead is for the Project to continue to expand into surrounding marshlands while preventing re-infestation of previously trapped habitats on state, federal and private lands,” Murphy said. “This will require the trapping team to work in much larger areas and expand the trapping zone on a much broader front.”

Based on current staffing, progress and field efforts, the Maryland Nutria Project estimates that it will eradicate nutria from the Eastern Shore by 2013. After that time, Project members will continue to monitor marshes and remove any nutria they find.

The Nutria Management Team, led by the U.S. Fish and Wildlife Service Chesapeake Bay Field Office, oversees the nutria eradication project. Other members of the Maryland Nutria Project include:

• The Chesapeake Marshlands National Wildlife Refuge Complex
• The U.S. Department of Agriculture Animal and Plant Health Inspection Service Wildlife Services
• The Maryland Department of Natural Resources
• The U.S. Geological Survey
• The University of Maryland Eastern Shore
• Tudor Farms

Learn more about nutria and the Maryland Nutria Partnership from the U.S. Fish and Wildlife Service and the Maryland Department of Natural Resources.