Black sea urchins in the Mediterranean Sea and the Gulf of Eilat are dying due to a deadly epidemic. The study by Tel Aviv University shows that the entire population of black sea urchins in the Gulf of Eilat was wiped out over a couple of months.
The numbers are thousands and researchers found no living evidence of black sea urchins at the site of the Mediterranean Sea. Such extensive mortality is also occurring in other countries like Saudi Arabia, Egypt, Jordan, Greece, and Turkey.
Due to this rate that dying sea urchins cause a threat to the coral reefs in that area. The researchers emphasized that sea urchins in general and long-spined Diadema Setosum, in particular, are considered key species essential for the healthy functioning of coral reefs.
The researchers caution “ 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. This situation is unprecedented in the entire documented history of the Gulf of Eilat”
Their research was published in the paper Frontiers in Marine Science and Royal Society Open Science.
Black Sea Urchins are the Protector of the Coral Reefs
Sea Urchins feed on the sea algae and prevent them from suffocating the corals that compete with them for sunlight. As Sea Urchins died coral life would be in danger.
The Main Reason for the Black Sea Urchins Death is Deadly Parasite
The studies were led by Dr.Omri Bronstein and Ph.D. students Rotem Zirler, Lisa-Maria Schmidt, Gal Eviatar, and Lachan Roth from the School of Zoology, Wise Faculty of Life Science, and The Steinhardt Museum of Natural History at Tel Aviv University.
The deadly pathogenic ciliate parasite is the source of the epidemic, it has spread from the Red Sea and the Mediterranean Sea.
Israel Nature and Parks Authority and emergency steps for protecting the Israel coral reefs are now under consideration.
The parasite ciliates cause the death of Black Sea Urchin in the Mediterranean Sea as they are spread to the red sea because of the proximity.
The first time the mass extinction of the Sea Urchins was recorded was in 1983 in the Caribbean Sea. That pathogen was also common when the black sea urchins died in the Caribbean Sea last year.
Dr. Bronstein said “ At first we thought it was some kind of pollution or poisoning, or a local chemical spill, from the industry and hotels in the north of the Gulf of Eilat, but when we examined additional sites in Eilat, Jordan, and Sinai, we quickly realized that this was not a local incident. All findings pointed to a rapidly spreading epidemic. Similar reports are coming in from colleagues in Saudi Arabia. Even sea urchins that we grow for research purposes in our aquariums at the Interuniversity Institute, and sea urchins at the Underwater Observatory Marine Park in Eilat, contracted the disease and died, probably because the pathogen got in through the pumping systems. It’s a fast and violent death: Within just two days a healthy sea urchin becomes a skeleton with massive tissue loss. While some corpses are washed ashore, most sea urchins are devoured while they are dying and unable to defend themselves, which could speed up contagion by the fish who prey on them.”
“This phenomenon, known as biological invasion, has extensive ecological implications, and is widespread in the eastern Mediterranean, especially along Israel’s coastline. We have been tracking the dynamics of this species’ invasion in the Mediterranean since its first appearance. In 2016 we discovered the first Diadema setosum sea urchin along Israel’s Mediterranean coastline—a single urchin at the Gordon Beach in Tel Aviv. For over a decade since the first discovery in Turkey, populations in the Mediterranean remained small and usually hidden. But since 2018 the sea urchin population in the Mediterranean has been growing exponentially, reaching a state of population explosion—with giant populations of thousands and even tens of thousands found in Greece and Turkey.
However, as we worked on studies summarizing the invasion of sea urchins in the Mediterranean, we began to receive reports on sudden extensive mortality. Supposedly the extinction of an invasive species is not a bad thing, but we must be aware of two major risks: First, we don’t yet know how this mortality and its causes might impact local species in the Mediterranean; and second, much more critical, the geographic proximity between the eastern Mediterranean and the Red Sea might enable the pathogen to quickly cross over to the natural population in the Red Sea. As we feared and predicted, this is what appears to have happened.”
The researchers are trying to preserve the black sea but in the Eilat coral reefs the window for preserving them is close to the Mediterranean Sea they are trying to preserve them.