The Center for Biological Diversity on Thursday filed a formal notice of intent to sue the National Marine Fisheries Service for its failure to develop a recovery plan for elkhorn and staghorn coral.

The two corals live in the Caribbean, including the Virgin Islands, and off the Florida coast. Although these corals have been protected under the Endangered Species Act since 2006, the Fisheries Service still has not yet developed a crucial and legally required recovery plan to avoid extinction and secure their future survival, the Center said in a press release issued Thursday.

“These elegant corals are heading toward an ugly end if we don’t act soon,” said Miyoko Sakashita, the center’s oceans director. “We need to start with halting their decline — only then will corals have a chance.”

National Marine Fisheries Service is an arm of the National Oceanic and Atmospheric Administration. NOAA spokesman Allison Garrett said that the agency is currently working on a recovery plan.

Sakashita said via email that recovery plans set goals for the conservation and recovery of a threatened or endangered species.

“They’re basically a road map to management measures and goals for helping bring a species back from the brink of extinction,” she said.

Recovery plans include measurable goals for removing the species from the Endangered Species List, the factors that limit the species’ viability, actions to address limiting factors and recovery cost estimates, she said.

Elkhorn and staghorn corals in 2006 became the first species to be protected under the Endangered Species Act due to the threat of global warming and ocean acidification.

Reefs in the Caribbean and Florida were once dominated by staghorn and elkhorn corals. In a few short decades, these corals have declined by more than 95 percent. Unusually warm waters have caused bleaching and mass mortality of elkhorn and staghorn.

Pressures from disease, fishing and pollution also have led to coral decline. And Caribbean waters are rapidly turning more corrosive because of ocean acidification, the center said.

“If we want to bring our oceans’ rich coral reefs back to life, we’ll need to take really decisive action to reduce greenhouse gas emissions. Otherwise that pollution will wipe out the reefs by mid-century,” Sakashita said.

The press release indicated that recovery plans are the main tool for identifying actions necessary to save endangered species from extinction and eventually be able to remove their protection under the Endangered Species Act.

Species that have had dedicated recovery plans for two or more years are far more likely to be improving than those without recovery plans.

The timely development and implementation of a plan is critical to saving elkhorn and staghorn corals because it will specifically identify what’s necessary to save them, such as habitat restoration and protection.

Thursday’s 60-day notice of intent to sue is a prerequisite to filing a lawsuit under the Endangered Species Act, the press release indicated.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 350,000 members and online activists dedicated to the protection of endangered species and wild places.