Elkhorn Coral

A reef-building coral of the Caribbean and western Atlantic, named for the broad, branching antler-like shape its colonies grow into, once the single most important structural coral on Caribbean reefs, forming dense stands in shallow water that dissipated wave energy and sheltered enormous numbers of fish and invertebrates. Like other reef-building corals it depends on an obligate mutualism with photosynthetic algae living in its tissue, and it reproduces both by fragmentation, broken branches regrowing into new colonies, and by a synchronized mass spawning a few nights each year timed to the lunar cycle. A wave of white band disease beginning in the late 1970s, compounded by warming-driven bleaching and hurricane damage, has eliminated an estimated 80 to 98 percent of the species' Caribbean population since, one of the fastest documented collapses of any reef-building coral.