Staghorn corals face the many threats that are impacting coral reefs globally. At present, around one third of the world's reef-building corals are threatened with extinction. The principal threat to corals is the rise in sea temperature associated with global climate change. This leads to coral bleaching, where the symbiotic algae are expelled, leaving the corals weak and vulnerable to an increasing variety of harmful diseases. Climate change is also expected cause more extreme weather incidents and to increase ocean acidification, which impairs the coral's ability to form a skeleton. These global threats are compounded by localised threats from pollution, destructive fishing practices, invasive species and human development (5).
Staghorn corals are considered to be environmentally sensitive corals that require clear, well-circulated water. Unlike other corals, which can obtain nourishment from zooplankton, staghorn corals are almost entirely dependent on the zooxanthellae for food. This means that sunlight is essential, and they are particularly sensitive to any human activities that increase water turbidity, reducing light availability (3).
Two of the three Acropora species in the Atlantic were once very abundant, but in recent decades have remained at low levels of abundance, with no signs of recovery and in some areas, continued decline. These species are believed to be most greatly threatened by disease, temperature-induced bleaching, and physical damage from hurricanes. Threats from anthropogenic physical damage (e.g. vessel groundings, anchors, divers, snorkelers), coastal development, competition and predation are deemed to be moderate. The threat from collection or harvest was deemed abated by effective national and international regulations (3).
Acropora species constituted 13 percent of the global coral trade between 1985 and 1997. Coral is harvested for building materials, curios, jewellery, and for aquariums. Staghorn corals are more common in the dead coral trade, rather than the live aquarium trade (6).