NEW ORLEANS — The U.S. Fish and Wildlife Service has met the deadline for decisions about whether 757 species need or should be considered for federal protection, an official of a nonprofit that sued the agency said Thursday.

About 400 species will get more study, 176 won protection under the Endangered Species Act and decisions about four Florida plants should be announced within the next week or so, said Noah Greenwald, endangered species director of the Center for Biological Diversity, created to save plants and animals from extinction.

In addition, the agency has until Sept. 30 to decide whether the Pacific walrus needs protection, he said.

“Now they have a whole bunch more work” on the hundreds of species that require further study, Greenwald said.

The good news is that nearly 80 species reviewed under a pair of 2011 settlements with the Tucson, Arizona-based center didn’t need protection — often because of Fish and Wildlife Service work with private landowners and state, private and nonprofit agencies to help their recovery, said Jeff Fleming, a spokesman for the federal agency.

He said more than a dozen already protected by the act improved enough since 2010 to be upgraded from endangered to threatened, like the manatee, or removed from the list like the Louisiana black bear.

Unfortunately, Greenwald said, the agency found Wednesday that two species of tiny beetles proposed for protection in 1984 and 1994 cannot be protected because they’ve been wiped out.

The same day, the Fish and Wildlife Service proposed endangered status for a 10-inch-long Alabama salamander called the Black Warrior waterdog and threatened status for the Louisiana pine snake, a 4- to 6-foot-long snake that lives in pocket gopher burrows in west Louisiana and east Texas.

The salamander, also called the mudpuppy, the Alabama waterdog, and the West Sipsey Fork waterdog, is nocturnal and never loses its gills, according to the Alabama Department of Conservation and Natural Resources.

Poor water quality has eliminated the salamander from much of its historical habitat, the Fish and Wildlife Service news release said, noting that the animal’s external gills and highly permeable skin make it particularly vulnerable to drops in water quality and oxygen concentration.

“The Black Warrior waterdog is not the only species struggling to survive in the Black Warrior River Basin,” the news release said. “Fifteen other aquatic species are currently federally protected in the basin’s rivers and streams, including snails, fish, mussels, turtles, and amphibians.”

The agency also proposed designating 669 miles in 11 tributaries of the Black Warrior River Basin as critical habitat for the salamander. Since those areas overlap 165 river miles already named critical habitat for other species, it would add 504 to the total.

Such designation requires U.S. Fish and Wildlife Service approval of federal contracts affecting an area.

“The decline of the Black Warrior waterdog indicates a decline in water quality,” said Cindy Dohner, the service’s southeast regional director. “By proposing to conserve the waterdog, we hope to work with partners to improve water quality within the entire basin to benefit people and all aquatic species.”

Louisiana pine snakes once were found in 14 Texas counties and nine Louisiana parishes, but now live in four parishes and five counties.

They live only in longleaf pine forests, an ecosystem that requires fires every three to five years to burn off shrubbery and keep the ground open for the green plants that are the main food for Baird’s pocket gophers, the snakes’ main food.

Slow-growing longleaf pine once covered 90 million acres from Virginia to East Texas. But its long, tall trunks, branching out only at the very top, made it popular timber. It’s now found on about 3.4 million acres.