Mysterious Disease Threatens World-Famous Diving Sites

A deadly and fast-moving disease affecting sea urchins poses an urgent threat to the coral reefs that attract divers from all over the world to the Red Sea. 

According to a new study from Tel Aviv University in Israel, a deadly epidemic of an unidentified plague has decimated black sea urchin populations in the region, entirely eliminating their populations in some areas. Sea urchins are a key species for the health of coral reefs, and their disappearance could threaten the very existence of some Red Sea reefs. 

"The sea urchins are the reef's 'gardeners'–they feed on the algae and prevent them from taking over and suffocating the corals that compete with them for sunlight," explains Dr. Omri Bronstein.

Scientists first noticed the disease in the waters around Greece and Turkey at the beginning of the year. In just a few months, it has spread through the Suez Canal to the upper part of the Red Sea, including the Gulf of Aqaba. It's been observed to kill healthy sea urchins within 48 hours.

The Gulf of Aqaba is one of the world's most-popular scuba diving destinations, drawing hundreds of thousands of divers annually to the coasts of Israel, Jordan, and Egypt. 

Although it hasn't been identified, they believe the plague is likely being caused by a pathogenic ciliate parasite that previously destroyed the population of sea urchins in the Caribbean Sea in the 1980s. That region's coral reefs have since declined by 90 percent  after being choked in algae due to the loss of these grazer species. The situation is so dire that the Israel Nature and Parks Authority is considering emergency steps to protect the reefs.

"It must be understood that the threat to coral reefs is already at an all-time peak, and now a previously unknown variable has been added," Bronstein said. "This situation is unprecedented in the entire documented history of the Gulf of [Aqaba]." 

The study predicts that the entire population of black sea urchins in the Mediterranean Sea and Red Sea could die, and the species will need to be bred and reintroduced by humans to triage the threat to the region's coral reefs.