Designating critical habitat for the endangered Mississippi gopher frog would cost about $9,600 a year over 20 years, for a total of $102,000, said the U.S. Fish and Wildlife Service.

The gopher frog is the only frog in the Southeastern United States listed as endangered or threatened. It lives only in Mississippi, in ponds so shallow they dry up in summer.

The federal agency proposed nearly 2,000 acres in Forrest, Harrison, Jackson and Perry counties as critical habitat for the frogs, named because they often live in burrows dug by gopher tortoises.

It proposed the critical habitat in June — about five weeks after the Gulf Restoration Network and Center for Biological Diversity threatened to sue unless the federal and state governments acted to protect the fragile habitat.

The agency is taking public comments about the economic study until Jan. 11.

Most of the land is owned by the federal government; 96 acres are owned by the state and 470 acres are privately owned.

Mississippi gopher frogs once lived in longleaf pine forests from western Alabama to southeast Louisiana. Timbering all but eradicated those forests.

They now live in only a few spots in south Mississippi.

Scientists believe fewer than 100 mature adults live in the wild. Five zoos — in Detroit, New Orleans, Memphis, Miami and Omaha, Nebraska — have been breeding or raising them.

Online:

Gopher frog facts:  http://www.fws.gov/southeast/publications/gopher.pdf

Economic study: http://tinyurl.com/24wve7d