Twenty coral species—ten times the number listed previously—are the newest animals slated for protection under the Endangered Species Act. The ruling, announced Tuesday evening by the U.S. National Oceanic and Atmospheric Administration (NOAA), did not come with restrictions on "taking" corals—harming them directly by collecting them or indirectly by altering their habitat—but officials haven't ruled out such restrictions for the future.

The listing of 20 species at once makes this the largest Endangered Species Act (ESA) ruling ever. But it could have been even larger, said Eileen Sobeck, assistant administrator with NOAA Fisheries: 83 species of coral had been proposed for listing.

Reef-building corals around the world are suffering the effects of ocean acidification, rising ocean temperatures, and pollution. A frequent symptom of damage is bleaching: An entire reef may turn white as the corals expel the symbiotic algae that live inside them. (See "Giant Coral Die—Off Found-Gulf Spill 'Smoking Gun?'")

The newly listed species are not going extinct now, said David Bernhart, a biologist with NOAA Fisheries Service in St. Petersburg, Florida, but there's a good possibility that they might in the foreseeable future. That's why these 20 species—which include pillow corals, three species of star corals, and rough cactus coral—have been classified as "threatened," rather than "endangered." (Learn more about how climate change affects coral reefs.)

"Most of these species, particularly in the Caribbean, have started to experience some impacts from bleaching and elevated temperatures and disease," Bernhart said.

They're not the first coral species to garner ESA protection. The Caribbean's elkhorn and staghorn corals were listed as threatened in 2006. But the current group is flung across a much wider geographic area.

Fifteen species inhabit U.S. territorial waters in the Indo-Pacific region, around American Samoa, Guam, the Commonwealth of Northern Mariana Islands, and the U.S. Pacific Remote Islands—a national monument that includes atolls in the Line and Marshall Islands. The five remaining species inhabit the Caribbean around Florida, the U.S. Virgin Islands, and Puerto Rico.

Limited Protection for Now

Other federal agencies will be the ones most affected by this newest ruling, said Sobeck. As she explains, if an agency like the Environmental Protection Agency or the Army Corps of Engineers wishes to work in an area that might affect a protected coral species, it must first consult with NOAA to arrange the proper permits. (See "Digging Up the Seafloor Makes Coral Reefs Sick.")

Activities like fishing and tourism remain unaffected for now, as does fertilizer use on land, the runoff from which can pollute coastal waters where corals live. If officials want to institute regulations to protect any of the newly listed corals—by, say, designating the kind of no-take zones that already apply to elkhorn and staghorn corals—they have to go through a separate process. That process, said Sobeck, would include economic impact reviews as well as public comment periods.

The decision to list the 20 new coral species came after an extensive review and comment period, Sobeck noted. Both the public and researchers provided a mountain of information on the various species under consideration. "I feel quite confident that we have a very robust, science-based decision regarding these 20 species," Sobeck said.

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