Elkhorn coral (Acropora palmata)
Critically endangered on the IUCN Red List.
Acropora palmata is found in the western Atlantic and around the Caribbean It is one of the fastest growing corals, and can grow up to two metres tall. Although it can easily out-compete other corals due to its size, it is very fragile and is often damaged by storms. It is described as a hermatypic, or reef-forming coral, as it forms large limestone structures by gradually depositing calcium carbonate. This species usually reproduces sexually, and many corals release their gametes at the same time, always just following a full moon.
Global warming, which is causing a rise in sea temperature, is the main threat to A. palmata. The algae that live within the coral cannot survive, which leads to coral bleaching and an increase in the rate of disease. This species is especially at risk, at it relies entirely on the algae for food.
The trade of A. palmata is restricted, and it is found in some marine protected areas. Attempts have been made to restore the coral reefs in the Florida Keys National Marine Sanctuary, but with limited success.
Photo: Marcin Smok.