At the Aquarium
Staghorn corals are found in our Live Coral exhibit in the Tropical Pacific Gallery.
These corals are found in the Indo-Pacific and Atlantic Oceans, mostly between 25 N to 25 S in suitable habitats. The Indo-Pacific corals are distributed from the west coast of Central America to the Red Sea and East Africa, with the most concentration in the “Coral Triangle” area of the Solomon Islands, Papua New Guinea, Indonesia, East Timor, Philippines, and Malaysia. The Atlantic group consists of two distinct species and one hybrid, found in the Bahamas, south-western Gulf of Mexico, and Caribbean coasts of Central and South America.
Staghorn corals require clear, oxygenated, warm tropical waters and they can live to a depth of approximately 98 feet (30 meters) with gentle wave action.
Staghorn corals form various shapes, from staghorn or upright branches to flat, plate-like structures and round, mounded clumps. Coral structures are built by many small animals known as polyps. These soft-bodied polyps have tentacles used for capturing prey. Each polyp will attach to a hard substrate and build its calcareous outer skeleton known as a corallite. The polyps live inside their corallite, extending their tentacles to capture prey. They have a symbiotic relationship with zooxanthellae, or photosynthetic algae, living within their tissues. Photosynthesis by the zooxanthellae provides the majority of the corals’ food, with food caught in its tentacles providing the remainder. These brightly colored corals may be green, blue, pink, or purple. They may also be red, brown, yellow, or cream colored. Tentacles tend to be white. Their zooxanthellae are a golden brown color.
A single corallite may be less than 0.12 inches (3 millimeters). Staghorn coral branches can grow to over 6.5 feet (2 meters).
They receive the majority of their nutrition from photosynthetic zooxanthellae living within their tissues, with the remainder from plankton captured with their tentacles.
Staghorn corals reproduce both sexually and asexually. Sexual reproduction occurs when conditions are optimal. Eggs and sperm are released into the water where fertilization takes place. The high volume of gametes released often turn the water a milky white. Most Great Barrier Reef staghorns sexually reproduce soon after the full moon, from October to December. After fertilization takes place, the resulting larvae may settle quickly onto the reef or drift hundreds of miles away before settling on a substrate. Once settled, they secrete a calcareous material that will build their skeleton. Asexual reproduction occurs when a branch breaks off, reattaches to a substrate, and continues growing.
Acroporas grow fast in order to out compete other corals and take over more reef space.
Coral polyps can live from two years to hundreds of years.
Coral reefs are in trouble worldwide from silting, bleaching, ocean acidification, climate change, disease and human activity. Deforestation and building activities on land cause soil to be washed from the land into the water, covering the reef. When a reef becomes silt covered, the zooxanthellae are no longer able to photosynthesize. Staghorn corals are very sensitive to water temperature. When water temperature rises, corals may expel their zooxanthellae on which they depend for much of their nutrition, a phenomenon known as bleaching. Ocean acidification, caused by the ocean absorbing massive quantities of carbon dioxide, is changing the ocean’s pH to become more acidic. A more acidic ocean has a direct impact on animals that make calcareous skeletons or shells. Climate change is causing more impacts on corals such as sea level rise, damage from increased storm frequency or intensity, and possible change in ocean circulation patterns. Any or all of the above serve to weaken the coral which opens the way for various disease causing pathogens or invasive species. Destructive fishing practices, anchoring on a reef, and trawls dragging across reefs serve to further destroy reefs.