More than 500 river miles have been designated critical habitat for a threatened fish species once found in Louisiana and Mississippi but now known only in part of its historic Mississippi range.
The Center for Biological Diversity and the U.S. Fish and Wildlife Service said Wednesday that the habitat designation affects the Pearl darter, a 2½-inch-long (6-centimeter-long) fish named for the Pearl River, but which 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% of the fish’s historic range.
The species has been gutted in Mississippi and Louisiana because of oil and gas developments, dams, mining, urbanization and agriculture. The critical habitat designation includes a section in the Pearl River basin where the fish can be reintroduced and other areas across 13 Mississippi counties in the Pearl River and Pascagoula River basins.
“Protecting what’s left of their habitat gives Pearl darters a fighting chance,” Will Harlan, Southeast director at the Center for Biological Diversity, said in a news release. “Dams and pollution have hammered these tiny fish, but they’re still clinging to survival in these key rivers.”
The recent designation adds an additional layer of protection, requiring any federally funded or permitted project to consult with the Fish and Wildlife Service to ensure the Pearl darter’s habitat is not harmed by a proposed activity, the Tucson, Arizona-based nonprofit said.
At least two other threatened species — the Gulf sturgeon and yellow blotched map turtle — also occupy the Pearl darter’s designated critical habitat and will benefit from the protections. Harlan said a number of other aquatic animals will also benefit, including mussels and crayfish.
The Pearl darter is a small, snub-nosed fish with a black spot at the base of its tail fin. Darters live on river bottoms and use the spaces between rocks for hiding and breeding.
After mating, female Pearl darters bury eggs in gravelly river substrate. Habitat destruction has clogged river bottoms with silt that inhibits the survival of adult Pearl darters and their offspring.
The darter was first placed on the waiting list for federal protection in 1991. The Center first petitioned for the species’ protection in 2004 and in 2010 filed a lawsuit over delays.
The fish finally gained protection as threatened under the Endangered Species Act in 2017.