The black sea urchin in both the Mediterranean Sea and the Gulf of Eilat in Southern Israel faces a deadly epidemic, according to a series of new studies.
“We predict that in a short period, the entire population of these sea urchins, in both the Mediterranean and the Red Sea, will get sick and die,” said the lead researcher, Omri Bronstein, in a press statement.
Bronstein is a senior lecturer from the School of Zoology, Wise Faculty of Life Sciences, and The Steinhardt Museum of Natural History at Tel Aviv University.
The severity of the epidemic was such that the site is now devoid of living black sea urchins, with only skeletons remaining. Similar devastation has been observed at other locations in the Gulf of Eilat.
The studies note that this extensive mortality is also occurring in other countries of the region, including Jordan, Egypt, Saudi Arabia, Greece, and Turkey.
The researchers say that the mass mortality of sea urchins in the Mediterranean Sea has spread to the Gulf of Eilat, posing a grave threat to the coral reef.
Black sea urchins play a crucial role as a key species in maintaining the health of coral 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,” said Bronstein.
The current situation presents an unprecedented threat to coral reefs, according to the researchers, adding that it surpasses anything documented in the history of the Gulf of Eilat.
The researchers hypothesize that a pathogenic ciliate parasite, which previously caused the extinction of sea urchins in the Caribbean during the 1980s, is the source of this deadly epidemic. This parasite irreversibly damaged the coral reef as the sea urchins vanished, leading to uncontrolled algae growth that blocked sunlight from reaching the corals.
Initially, the researchers suspected pollution, poisoning, or a local chemical spill as the cause. However, after examining additional sites in Eilat, Jordan, and Sinai, they realized that this was not a localized incident.
“All findings pointed to a rapidly spreading epidemic,” said Bronstein, who also mentioned receiving similar reports from colleagues in Saudi Arabia.
Even sea urchins raised for research purposes in aquariums at the Inter-University Institute, as well as those at the Underwater Observatory Marine Park in Eilat, contracted the disease and perished. It is likely that the pathogen infiltrated through the pumping systems, Bronstein explained.
“It’s a fast and violent death: within just two days, a healthy sea urchin becomes a skeleton with massive tissue loss,” he said.
These sea urchins are now absent in the Gulf of Eilat and rapidly disappearing from other regions of the Red Sea to the south, said Bronstein.
While the current epidemic was first identified in the Mediterranean, it has swiftly reached the Red Sea.
The first reports of mass mortality reached Bronstein several months ago from colleagues in Greece and Turkey.
“If we want to establish a broodstock population, we must do it today by preserving healthy individuals from the Israeli Mediterranean before the disease, spreading from the north, reaches this area,” said Bronstein. “It is absolutely necessary if we wish to ensure the survival of this unique species that is so critical to the future of coral reefs.”
Following the studies, an urgent report describing the current situation has been submitted to the Israel Nature and Parks Authority, prompting considerations for emergency measures to protect Israel’s coral reefs.
