NEW ORLEANS — The U.S. Fish and Wildlife Service is proposing “threatened” status for the Pearl darter, a 2½-inch-long fish once found in 16 Mississippi and Louisiana counties and parishes but now found in only a fraction of its historic range.
The fish is named for the Pearl River, but hasn’t been found in that watershed for more than 40 years. However, the wildlife service began checking again this summer, agency spokeswoman Connie Dickard said Tuesday. Known Pearl darter populations are dotted along 279 miles of the Pascagoula River system in southeast Mississippi, about 43 percent of its historic range.
Mississippi lists the fish as endangered — but that classification does not provide any legal protection for the Pearl darter’s habitat, and habitat degradation is the biggest threat it faces, the U.S. Fish and Wildlife Service said in a proposal to be published Wednesday.
Fracking and horizontal drilling also pose a threat to the species, since the waste is stored in open pits or storage facilities that can fail or overflow, according to the proposal.
“There is currently no routine water quality monitoring in areas where the Pearl darter currently occurs, so it is unlikely that the effects of a leak or spill would be detected quickly to allow for a timely response,” scientists wrote.
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, according to the proposal.
“Though the proposed project is not directly within known Pearl darter habitat, the lakes will decrease water quantity entering the lower Pascagoula Basin, and will likely concentrate pollutants, reduce water flow, and alter (the) downstream food web,” the scientists wrote.
Hank Bart, a professor of ecology and evolutionary biology who has studied the species, said he thinks the Pearl River Basin population died out because low dams kept the fish from swimming upriver to spawn.
“The Pascagoula River population survives, and it seems to be a reasonably healthy population. And it’s because the Pascagoula River isn’t impounded,” he said.
Pearl darters are sensitive to water quality, so their presence indicates a good water system, said Tierra Curry, a senior scientist at the Center for Biological Diversity, a Tuscon, Arizona-based nonprofit that reached settlements in 2011 requiring the government to consider protections for more than 800 plant and animal species.
“It’s bad for the Pearl River system that Pearl darters are whacked out, because it means the entire system has pretty bad degradation. The message there would be we need to do a better job taking care of our streams and rivers,” Curry said.
Darters live on the river bottom, hiding and breeding between rocks in spaces small enough to be filled by silt from runoff upriver, Curry said.