Staghorn coral: Acropora cervicornis
Genus/Species: Orthalicus reses
Common Name: Stock Island tree snail
Federal Status: Threatened
FL Status: Federally-designated Threatened
FNAI Ranks: Not ranked
IUCN Status: CR (Critically Endangered)
Staghorn coral received its common name due to its resemblance to male deer antlers (National Oceanic & Atmospheric Administration, n.d.). Its tan-colored branches can reach a length of 6.5 feet (two meters). The staghorn coral’s upper growth is determined by wave forces, while the lower growth is determined by the availability of light and the quantity of suspended sediments (National Park Service, n.d.). Staghorn coral also contain stinging cells (nematocysts) on their tentacles that are used for capturing food. It is the fastest growing species of coral in western Atlantic waters, growing at a rate of four to eight inches (10.2-20.3 centimeters) every year (National Park Service, n.d.).
Staghorn coral harbors symbiotic (depends on the host as the host depends on it to survive) zooxanthellae [autotrophic (creates own food through photosynthesis) dinoflagellates] which photosynthesize and provide energy in the form of carbon compounds (amino acids, glucose, etc.) to the colony. They also feed on zooplankton (National Oceanic & Atmospheric Administration, n.d.).
Staghorn coral primarily reproduces asexually; however, they are capable of producing sexually. During asexual reproduction, or asexual fragmentation, branches of coral break off and attach to the ocean floor. Sexual reproduction occurs only once per year in August or September. Staghorn coral is a broadcast spawner - releases eggs and sperm into the water for fertilization. Larvae will live in plankton for several days until a proper habitat is located to settle in and metamorphose. Observations from recent years have supported that larvae rarely survive to metamorphose and develop colonies (National Oceanic & Atmospheric Administration, n.d.).
Habitat and Distribution
Staghorn coral can grow anywhere from the water surface to 100 feet (30.5 meters) below the surface in marine waters (National Park Service, n.d.). This species can be found from Boca Raton, Florida, south to Venezuela (National Park Service, n.d.).
As global climate change continues, all coral face the threat of bleaching, sea level rise, ocean acidification, and increased frequency and intensity of hurricanes. Bleaching occurs when the coral’s habitat is degraded enough to the point where their symbiotic zooxanthellae (dinoflagellate) are expelled by the host, thereby causing loss of pigmentation to the colony. Global climate change causes an increase in the temperature of marine waters which is detrimental to the coral. Ocean acidification, also a byproduct of global climate change, can impair coral skeleton calcification rates and erode existing reefs. Hurricanes also pose a threat as their intense storm conditions can cause damage to the coral. Staghorn coral also face the threat of disease like the white plague disease, a bacterial (Aurantimonas coralicida) disease that destroys tissue. Sedimentation of its aquatic habitat threatens the staghorn coral, as the increased sediment prevents light from reaching the lower portion of the coral preventing lower growth. Other threats include extreme variations of water temperature and salinity, and physical colony damage caused by anchors and boats.
Conservation and Management
The staghorn coral is protected as an Endangered species by the Federal Endangered Species Act and as a Federally-designated Endangered species by Florida’s Endangered and Threatened Species Rule.
Other Informative Links
Animal Diversity Web
International Union for Conservation of Nature
National Park Service
U.S. Geological Survey
Printable version of this page
National Oceanic and Atmospheric Administration. (n.d.). Staghorn Coral (Acropora cervicornis). Retrieved July 20, 2011, from NOAA Fisheries Office of Protected Resources: http://www.nmfs.noaa.gov/pr/species/invertebrates/staghorncoral.htm
National Park Service. (n.d.). Staghorn Coral. Retrieved July 20, 2011, from Dry Tortugas: http://www.nps.gov/drto/naturescience/staghorncoral.htm
Image Credit FWC