by B. N. Sullivan
When we think of endangered or threatened species in the ocean, we usually think of sea turtles, or whales, or certain kinds of fishes. Unfortunately, populations of some coral species also have been seriously depleted, and some are at risk for extinction.
According to the language of the Endangered Species Act of 1973 (ESA), a species is considered to be 'endangered' if it is in danger of extinction throughout all or a significant portion of its range. A species is considered 'threatened' if it is likely to become an endangered species within the foreseeable future.
The pretty Staghorn coral (Acropora cervicornis) in the center of the photo above is officially classified as a 'threatened' species. Acroporid corals like this one are important reef-building corals, and they provide a habitat for fishes and invertebrates..
In the United States, this species is found in the Florida Keys, and along the Atlantic coast of Florida as far north as Boca Raton, but it is absent from U.S. waters in the Gulf of Mexico, according to the National Oceanic and Atmospheric Administration (NOAA). A. cervicornis does occur in the western Gulf of Mexico, and also in the Bahamas, the Caribbean islands, and Venezuela.
In a few places (very few) it is still possible to see large stands of this antler-shaped coral, but more often these days, the species exists only as small colonies, like the one in the photo above. In fact, reef surveys have shown that, since 1980, populations of A. cervicornis have collapsed, declining by up to 98% throughout the range.
So, what is responsible for such a marked decline? The number one threat to Acroporid corals is White-band Disease, a devastating, rapidly spreading disease that destroys the tissues of the coral. The cause of White-band Disease is poorly understood, but the results are devastating.
A. cervicornis is "particularly susceptible to damage from sedimentation and is sensitive to temperature and salinity variation," according to NOAA. In addition, NOAA lists hurricanes, increased predation, bleaching, algae overgrowth, and human impacts among the factors that threaten Acroporid corals.
Fortunately, conservation efforts have been initiated to manage and protect what remains of the A. cervicornis population. In some areas -- such the U.S. Virgin Islands, Puerto Rico, and the Florida Keys National Marine Sanctuary (FKNMS) -- restoration activities also have been undertaken following hurricanes, ship groundings, and the like. Nevertheless, restoration efforts, such as re-attachment of broken coral fragments and attempts to culture and settle coral larvae, are painstaking and have had limited success.
What you can do:
- When you snorkel, dive, or go to the beach, NEVER stand on or touch coral.
- Do not collect coral, dead or alive. (Federal and State regulations prohibit collection of all soft and hard corals.)
- Divers should maintain proper buoyancy, be careful not to kick corals when swimming over them, and keep gear items such as hoses, gauges, etc. secured so that they do not drag across the coral.
- Boaters should use mooring buoys wherever they are available. If you must anchor, avoid doing so near coral; instead of throwing your anchor, swim it down and place it on sand.
More information: NOAA Fact Sheet: Atlantic Acropora corals - 2-page 'pdf' file