JACKSON, Miss. — A 2½-inch-long (6-centimeter-long) fish once found in Louisiana and Mississippi but now known only in part of its historic Mississippi range will soon be designated as threatened, federal authorities said Tuesday .

The U.S. Fish and Wildlife Service proposed the listing last year and will make it official on October 20.

The pearl darter is named for the Pearl River, but is no longer found there or in any of its tributaries. Instead, remaining populations are found along the Pascagoula River system in southeast Mississippi, about 43 percent of the fish’s historic range.

The listing will have little impact on private property owners, U.S. Fish and Wildlife Service spokeswoman Connie Dickard said. However, federally-funded projects will have to take precautions not to harm the fish. Because the darter’s range overlaps two other threatened species, the Gulf sturgeon and yellow-blotched map turtle, government agencies are already likely taking those precautions.

The federal agency says the fish is threatened by pollution from erosion, sand and gravel mining, wastewater plants and factories. The small population means a catastrophic pollution spill or poor genetic diversity also threaten the darter’s survival. A proposal to create two recreational lakes by damming Little and Big Cedar Creeks, which flow into the Pascagoula River, could also cause problems for the fish, the agency has said.

It’s unclear how many of the fish remain. Biologists for the Mississippi Department of Wildlife, Fisheries and Parks conducted an extensive search for the darter in its namesake Pearl River and its tributary, the Strong River, over the last year, said Matt Roberts, the department’s research program coordinator. Nets, trawling, and DNA tests of water collected from the rivers found no evidence that the darter is still present there.

The news was better in the Pascagoula system. In addition to documenting known populations in the Pascagoula, Leaf and Chickasawhay rivers, Roberts said sampling confirmed the fish is present in some smaller tributaries, including Black Creek and Okatoma Creek.

“We will find them if we’re looking for them in that drainage,” Roberts said. “We know where to go.”

Dickard said the federal government will propose a recovery plan for the darter, but that process won’t even start for about two years. She said it’s unclear whether officials will try to reintroduce the fish to the Pearl River.

“When you recover a species, you do try to look for alternative locations and you do look to recover the historic range,” she said.

The darter was listed following a 2011 settlement requiring the government to consider protections for more than 800 plant and animal species. That settlement came following actions undertaken by the Center for Biological Diversity , a Tucson, Arizona-based nonprofit. The center hailed the listing of the darter and two other species Tuesday, saying it was pleased actions hadn’t been blocked by appointees of President Donald Trump.


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