According to the United States Fish & Wildlife Service (USFWS), the state of Maryland is finally free from one of its most destructive invasive pests. Introduced to the Delmarva Peninsula in the 1940s for the commercial fur market, large semi-aquatic rodents known as nutria have been wreaking havoc on Maryland’s coastal ecosystem for decades. After 20 years of collaborative efforts aimed at doing away with the destructive rodent once and for all, officials with the USFWS, the U.S. Department of Agriculture’s Wildlife Services, and the Maryland Department of Natural Resources say they’ve finally won the war against the orange-toothed, rat-like critter—at least on Maryland’s eastern shore.

“The Chesapeake Bay Nutria Eradication Project is an excellent example of foresight and collaboration,” said USFWS Director Martha Williams during a September 16 event at the Blackwater National Wildlife Refuge, where nutria have contributed to the destruction of more than 5,000 acres of valuable wetland habitat. “This project is a powerful case study for how federal and state agencies can work closely together to achieve a shared goal that benefits the environment and the community.”

Nutria, first brought to the United States in the 1800s, can weigh more than 20 pounds and reach 37 inches in length. By eating and removing critical root systems that lend stability to marshy soils, the invasive pests can cause marshes to disappear permanently and sea levels to rise. The marshes that nutria erase provide habitat for migrating and wintering waterfowl, spawning grounds for commercial fisheries including striped bass and blue crab, and homes for threatened and endangered species such as the black rail, the USFWS said in a recent press release.

“This project was only possible due to the outstanding collaboration between private, state, and federal partners. This, coupled with science-based wildlife management and research, led to eradication success,” said Kevin Sullivan, USDA-Wildlife Services State Director. “Historic tools, such as trapping and wildlife surveys, were integrated by wildlife biologists with new technology and detector dogs. These tools were applied by dedicated individuals to find nutria every day. Due to this hard work, partnership, and perseverance, we are excited to announce this destructive invasive species will no longer be damaging and destroying the marshes of Delmarva.”

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Maryland has been on the cusp of declaring nutria eradicated since 2015—when the last known nutria was removed from the eastern shore. Since then, eradication teams have shifted into a scaled-down “bio-security phase,” responding to reported sightings and assisting nearby Virginia with a nutria problem of its own. “After years of hard work and partnership, we have proven that eradication of this invasive species is possible,” said Maryland DNR Secretary Jeannie Haddaway-Riccio. “Maryland’s wetlands, particularly in this region, are special because of their ecological and economic importance but also because of their historic and cultural significance, and we have successfully protected them from this threat.”

According to the United States Department of Agriculture Animal and Plant and Health Inspection Service (APHIS), nutria have been documented in at least 20 states, with California being the most recent. With a reported population of nearly 25 million, Louisiana officials have placed a bounty on the aquatic rats of $6 per tail. Other states with known nutria populations include Texas, Florida, Georgia, North Carolina, Mississippi, Oregon, Washington, and Illinois.