A deadly epidemic is causing mass mortality of black sea urchins in the Mediterranean Sea and the Gulf of Eilat. The entire population of Black Sea urchins in Eilat was wiped out over a couple of months. Thousands of sea urchins living in a site near the northern shore of the Gulf of Eilat died out over the course of a few weeks. The epidemic was so severe, that today no living black sea urchins have remained at the site, only skeletons. The same has happened at other sites in the Gulf of Eilat.
The studies note that such extensive mortality is also occurring in other countries in the region, including Jordan, Egypt, Saudi Arabia, Greece, and Turkey. The researchers from Tel Aviv University sent us the distressing report that coral reefs, already alarmingly stressed, are at risk:
“Mass mortality of sea urchins in the Mediterranean Sea has spread to the Gulf of Eilat and threatens to destroy the coral reef. Within just two days a healthy sea urchin becomes a skeleton with no tissues,” they report.
The source of the pandemic points to a pathogenic ciliate parasite which in the 1980s eradicated the entire sea urchin population in the Caribbean, damaging the coral reef irreversibly. The current epidemic was first discovered in the Mediterranean but quickly reached the Red Sea, where it is spreading at an unprecedented rate.
Sea urchins in general, and black sea urchins specifically, are considered key species essential for the healthy functioning of coral reefs. Following the studies, an urgent report describing the current situation was submitted to the Israel Nature and Parks Authority, and emergency steps for saving the coral reef are now being considered.
The mass mortality reminded the TAU researchers of one of the most famous and devastating events in the history of marine ecology: the disappearance of the sea urchins in the Caribbean. Until 1983 the Caribbean coral reef was a thriving tropical reef, quite similar to the coral reef in the Gulf of Eilat. Once the sea urchins disappeared, the algae multiplied without control, blocked the sunlight from reaching the corals, and the entire reef changed irreversibly – from a coral reef to an algae field.
The studies were led by Dr. Omri Bronstein and PhD students Rotem Zirler, Lisa-Maria Schmidt, Gal Eviatar, and Lachan Roth from the School of Zoology, Wise Faculty of Life Sciences, and The Steinhardt Museum of Natural History at Tel Aviv University. The papers were published in Frontiers in Marine science and Royal Society Open Science.
