Mass Death of Sea Urchins in the East Med Threatens Ecosystems

Sea urchins in the Eastern Mediterranean have been dying off at an alarming rate due to a pathogen, a development that threatens the Turkish and Greek prized coral reef ecosystems, researchers announced Friday.

According to a report in Daily Sabah, researchers spotted the first signs of the urchin plague in the Mediterranean Sea at the beginning of the year when an invasive species of urchin began falling sick in the waters around Greece and Turkey.

From there, the disease appears to have spread southward through the Suez Canal to the Red Sea.

The deadly epidemic has swept across the Red Sea and has killed an entire species of sea urchin, stripping their flesh and turning them into skeletons.

Just two months ago, thousands of black sea urchins (Diadema setosum) lived in the Gulf of Aqaba, in the northern tip of the Red Sea, keeping the corals there healthy by snacking on excess algae. Now, only their skeletons remain, after their tissue was consumed by a mysterious pathogen.

“It’s a fast and violent death: within just two days a healthy sea urchin becomes a skeleton with massive tissue loss,” Omri Bronstein, a senior lecturer in Zoology at Tel Aviv University, said in a statement.

“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.”

It was stated that these deaths, which were determined to spread over an area of ​​​​over 1,000 kilometers (621.3 miles) along the Mediterranean coasts of Greece and Turkey, could be temporarily beneficial but could have devastating consequences for other sea creatures.

A parasite killed Caribbean’s entire sea urchin population

A single-celled ciliate parasite microorganism in 1983 eliminated the Caribbean’s entire sea urchin population. Before the parasite plague, the Caribbean was home to thriving tropical reefs, but since losing the sea urchins, the reefs have been smothered by algal blooms that multiplied unchecked, blocking out sunlight and destroying around 90% of the region’s coral.

Ciliates seem to thrive in nutrient-rich shoreline habitats, while the disease seems to originate in calm water ports and harbors. Then it appears to spread through the water across a wide space, perhaps in currents, with floating vegetation or carried by migratory fish or sea birds.

The research on the mass mortality rates of invasive sea urchins in the Mediterranean was published as an article in the international journal of The Royal Society and was noted that in Turkey, the urchins were first seen in 2006 in Antalya’s Kaş offshore.

They then spread to the entire Eastern Mediterranean basin along with the coasts of Lebanon, Israel, Egypt and Libya.

The high temperatures and rapid warming in the Eastern Mediterranean are expected to speed up and intensify the pathogen epidemic in the region. Scientists stated mass deaths may be beneficial in terms of invasive species and will reduce the alien population, albeit temporarily.

The researchers also called for urgent regional cooperation in the measures against the spread of pathogens.

Related: Marine Heatwave Attracts Invasive Fish in the Mediterranean