Wildlife

Sea Urchins in Distress

A mysterious epidemic that began in the Mediterranean at the start of the year looks set to wipe out all of the Mediterranean and Red Sea’s urchins, and possibly their coral reefs too. A sudden and deadly epidemic sweeping across the Red Sea has killed an entire species of sea urchin, stripping their flesh and turning them into skeletons.

A sudden and deadly epidemic sweeping across the Red Sea has killed an entire species of sea urchin, stripping their flesh and turning them into skeletons. Just two months ago, thousands of black sea urchins (Diadema setosum) lived in the Gulf of Aqaba, in the northern tip of the Red Sea, keeping the corals there healthy by snacking on excess algae. Now, only their skeletons remain, after their tissue was consumed by a mysterious pathogen.

Scientists are unsure of the exact disease causing the mass die-off, but they suspect it is a pathogenic ciliate parasite — a single-celled microorganism — which in 1983 eliminated the Caribbean’s entire sea urchin population. Before the parasite plague, the Caribbean was home to thriving tropical reefs, but since losing the sea urchins the reefs have been smothered by algal blooms that multiplied unchecked, blocking out sunlight and destroying around 90% of the region’s coral.