Sea Urchin Die-Off Threatens Red Sea Coral Reefs, Israeli Scientists Say

The population of black sea urchins (Diadema setosum) in the Red Sea’s Gulf of Aqaba has been devastated by an unknown pathogen, Israeli researchers reported on Wednesday. The die-off is a threat to the gulf’s coral reef ecosystem since the urchins’ appetite for algae protects the coral from harmful algal blooms.

Disproportionate black sea urchin mortality was first observed in July in the Eastern Mediterranean Sea, where it is an invasive species. In January, scientists noticed it had spread to the Gulf of Aqaba. Since then, it’s begun spreading to the rest of the Red Sea.

In a paper published Wednesday in the Royal Society Open Science journal, Tel Aviv University scientists identified the cause of the unprecedented mass mortality event as a pathogen, rather than poisoning or pollution. They called on Israel’s Nature and Parks Authority to take action to protect the coral reef ecosystem, with the specific recommendation of establishing a captive population of black sea urchins.

The Gulf of Aqaba, also known as the Gulf of Eilat, is shared by Israel, Jordan, Egypt, and Saudi Arabia. Research has suggested that the gulf’s coral reefs might be more resilient to climate change than other reefs.

Earlier this year, Jordan submitted a request to UNESCO to declare its portion of the gulf a World Heritage Site because of its “high number of species, diverse number of habitats, high endemism, and remoteness.”