NEW ORLEANS — The U.S. Fish and Wildlife Service announced Monday that it is proposing threatened status for the Pearl River map turtle, seeking to grant added federal protections to an at-risk species found only in Louisiana and Mississippi.

“These native freshwater map turtles are at risk and need our help,” regional director Leopoldo Miranda-Castro said in a news release.

The agency said it also would seek protection for the closely related Pascagoula map turtle, found only in Mississippi, and three other species found in Alabama, Florida, Georgia and Tennessee because they look like the Pearl River turtle.

Without protecting the other species it would be difficult for enforcement agents to stop people from catching and selling Pearl River map turtles — one of the main threats to the species, according to a preview posted a day ahead of its planned publication Tuesday in the Federal Register.

The “threatened due to similarity” status would make it illegal to take the turtles out of the wild but wouldn’t require a recovery plan or other protections the Pearl River turtles will get if it is listed as threatened.

The map turtles’ name is derived from shell markings that resemble the contour lines on topographic maps. Map turtles are also called sawbacks because their shells have a central ridge that sometimes develops saw-like points.

Their intricate markings make them popular pets, the agency said.

“An analysis of online marketplace offerings in Hong Kong revealed that interest in turtles as pets is increasing, that many of the species offered for sale are from North America, and that there is a higher interest in rare species,” the proposal said.

One reason scientists aren’t designating critical habitat is that divulging that information would be a giveaway to poachers about where to hunt for the turtles, according to the proposal.

In addition to the Pascagoula species, the others protected as similar species are the Alabama map turtle, also found in Georgia, Mississippi, and Tennessee; Barbour’s map turtle living in Alabama, Florida, and Georgia; and the Escambia map turtle in Alabama and Florida.

By Associated Press