Federal wildlife officials are seeking endangered species status for a freshwater mollusk — the “magnificent ramshorn snail” — that’s indigenous to Southeastern North Carolina but hasn’t been seen in the wild for nearly two decades.
Scientists also hope to get two sites in the state declared as “critical habitat” for the snail in hopes that it can one day be reintroduced to the wild.
The “magnificent ramshorn snail,” larger and more rare than the common ramshorn snail, is only known to exist now in captivity, in three places:
▪ at N.C. State University’s College of Veterinary Medicine in Raleigh.
▪ at a hatchery operated by the state Wildlife Commission in Marion.
▪ and at a private residence near the coast.
Between them, the three sites have a total of about 1,000 of the snails, which are North America’s largest air-breathing freshwater snails.
Originally in two ponds
All those snails are descended from populations originally found at two ponds in Brunswick County. But they haven’t been found at those or the two other ponds, all within the Cape Fear River Basin, where the snails are known to have existed, since 2004.
In a news release about the effort to get the snails declared endangered, the Fish & Wildlife Service said having the snails in captivity doesn’t necessarily guarantee the species’ survival.
“A catastrophic event, such as a severe storm, disease, or predator infestation, affecting the captive populations could result in the near extinction of the species,” the release said.
The U.S. Fish & Wildlife Service says that the four sites where the magnificent ramshorn snail were originally found likely were ponds created by old mill dams. They made the perfect habitat for a creature with an inch-and-a-half shell that can’t tolerate salt, needs a diverse and abundant plant diet, and can’t survive in flowing water.
Wildlife experts say the magnificent ramshorn likely was once found throughout the lower Cape Fear River basin, when most of the river was shallow and fresh, and would have been especially prevalent in rice plantations. When the river was dredged in the 1930s to allow cargo ships to come in, it caused tidal fluctuations to increase, sending salt water further inland.
Over time, according to a Fish & Wildlife report, the snails’ habitat changed further and could no longer support them. Scientists say global warming and sea level rise have increased saltwater intrusion into freshwater bodies, including through flooding resulting from hurricanes. The elimination of beaver dams through much of the river basin also has eliminated ponds that could have supported the snail, researchers say.
Changes in water chemistry resulting from land development and pest control likely damaged the snails’ habitat as well, the report said.
The magnificent ramshorn already is listed by the state as an endangered species, but the designation doesn’t offer protection from incidental harm, injury or death, and doesn’t protect the animals’ habitat except on state-owned land.
What federal endangered status would mean
Federal endangered species status, scientists say, would allow for conservation efforts both for the snail and its natural habitat so it can recover and thrive.
Fish & Wildlife officials would like to work with the owner of Orton Pond, east of the town of Boiling Spring Lakes, and Big Pond, also called Pleasant Oaks Pond. Both are in Brunswick County and both are known as former homes of the magnificent ramshorn.
Together they would provide about 739 acres of habitat at a projected cost of less than $21,000 per year, including administrative work and project modifications. Researchers also are looking at three other sites as possible places where the snails could be reintroduced, including Greenfield Lake, a former millpond that once was home to the magnificent ramshorn. Greenfield Lake is the centerpiece of a Wilmington park, but the water is presently too polluted to support the snail.
The Fish & Wildlife Service invites the public to comment on the proposal through Oct. 18 at https://www.regulations.gov.