Elkhorn coral (Acropora palmata) is consiered to be one of the most important reef-building corals in the Caribbean. This species of coral is structurally complex with many large branches. Despite its name, the coral structure more closely resembles that of moose antlers, as opposed to elk horns. These branches create habitats for many other reef species such as lobsters, parrot-fish, snappers, and other reef fish. Elkhorn coral colonies are incredibly fast growing with an average growth rate of 5-10 cm per year and can eventually grow up to 12 feet in diameter. The color of this coral species ranges from brown to a yellowish-brown. This color is a result of the symbiotic zooxanthellae that live inside the tissue of this coral species. Zooxanthellae is a type of algae which photosynthesizes to provide the coral with nutrients. The zooxanthellae are also capable of removing waste products from the coral. Historically, the majority of elkhorn coral reproduction has occurred asexually; this occurs when a colony of the coral breaks off and attaches to the substrate forming a new colony. It was believed that this resulted in low genetic variance amongst the remaining populations of elkhorn coral, however, recent research shows that the amount of sexual reproduction has been increasing and has resulted in more genetic diversity. Sexual reproduction occurs once a year in August or September when coral colonies release millions of gametes by broadcast spawning.