Apparently due to global warming, a tropical ecosystem of invasive species has transformed Israel’s coastline, a study published by Britain’s Royal Society scientific academy shows.

The Israeli coastline at Jaffa
The Israeli coastline at Jaffa.Credit: Moti Milrod

Zafrir Rinat Published on 10.01.2021

The wealth of species of local shellfish and snails on Israel’s Mediterranean coastline has declined by almost 90 percent in recent decades, according to a new study.

The decline represents the largest regional loss of diversity documented in a marine environment anywhere in the world, and scientists believe that the decline is related to global warming, which has led to a sharp increase in the temperature of the Mediterranean Sea. They also expect to find similar declines in other parts of the Mediterranean Basin.

The study, which was published last week in the Proceedings B biology research journal of Britain’s Royal Society scientific academy, was based on 119 samples of various species of molluscs – a category of animals that includes snails and shellfish. They were sampled at 16 sites along Israel’s Mediterranean coastline, from shallow water up to a depth of 90 meters (295 feet).

The research team compared the numbers of living molluscs that they found with previously reported population sizes, as well as estimates of their prevalence based empty shells found on the sea floor. The drop was greater than anything ever seen before.

The study was led by Dr. Paolo Albano, a marine biologist from the University of Vienna, whose team included researchers from Croatia and the United States, as well as Dr. Gil Rilov of the Israel Oceanographic and Limnological Research Institute in Haifa.

According to the research findings, in the shallower areas, the variety of species plummeted to 12 percent of what existed in the past in the soft sea bottom and to only 5 percent in the areas of sea floor that are rocky. About 60 percent of the species found in the shallower water aren’t surviving to their reproductive age.

At major depths, the rate of decline in the biodiversity was a smaller 50 percent.

“The magnitude was totally unexpected,” said Albano in an interview with The Guardian following publication of the study. “What I found was a desert, totally devoid of even common Mediterranean species.”

The murex, for example, a gastropod the excretions from which were used in ancient times to make purple clothing dye, was no longer found off the coast, Albano said.

Along Israel’s coast, an environment reminiscent of a tropical region has developed, populated by various invasive species, the scientists wrote. What has evolved is a “novel ecosystem” whose restoration to historical baselines appears unachievable, they stated.