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School of dolphins in the Red Sea, Egypt.Credit: Kristina Vackova/Shutterstock.com

World - ‘Common’ Dolphins on Israeli Coastline Decreased by 40% in Last 5 Years

It’s still unclear what factors have led to the dramatic decline in the number of dolphins, which were formerly commonly found across the entire Mediterranean

The population of the common dolphin, one of the two species that permanently live off Israel’s Mediterranean shoreline, is on a downward trend, dwindling by 40 percent in recent years. Apparently they now number fewer than 20, according to a study published last week.

The study was based on extensive work carried out between 2016 and 2021, with its results appearing in the journal Frontiers in Marine Science.

It’s still unclear what factors have led to the dramatic decline in the number of dolphins, which were formerly commonly found across the entire Mediterranean. There is a high likelihood that they got entangled in fishing equipment which injured them or caused their suffocation. For example, two dolphins found dead on Israel’s beaches in this period showed signs of such injuries. Other risk factors are pollution close to ports and disease. According to estimates, if these trends continue, this species could vanish from Israel’s coast by the end of this decade.

Across the Mediterranean there are currently several small local populations which live permanently close to shore. One of them lives mainly offshore between Ashdod and Ashkelon, at a depth of 15-30 meters. In recent years, a study of these dolphins was done by observation from vessels. The animals were photographed and identified by unique markings on their fins. Altogether, 25 adult dolphins were documented, as well as 12 calves with unique features. An additional 17 were not individually identified. One adult was seen 37 times. The study also found that the dolphins maintained close social ties between all the adults.

The study was led by Yali Mevorach from the Nature and Parks Authority, as part of a study she is conducting at the Morris Kahn Marine Research Station at Haifa University. Supervision and analysis of results were done by Dr. Aviad Scheinin, director of the apex predator lab at the research station and director of a nonprofit organization devoted to protecting marine mammals, as well as by a researcher from Sapienza University in Rome.

The study’s assumption was that at the start of the survey there were 25 dolphins living permanently along Israel’s coastline, but this number has declined to 15. Over a decade ago, pods of 19-22 dolphins could be seen, but in recent years only smaller groups are observed. Last month, for example, the maritime division of the Nature and Parks Authority reported seeing a group of nine common dolphins near Ashkelon. The pod was observed following a fishing vessel, in an attempt to eat fish caught in the boat’s nets.

According to experts, the condition of the common dolphin can be improved through the designation of maritime areas as nature reserves, where no fishing is allowed. In such areas, local fish can recover and serve as a food source for the dolphins. One of the most important dolphin habitats is now in an area slated to become such a marine reserve, but the process of declaring the area a reserve has not been completed yet.

The researchers in this study, including Scheinin, maintain that the definition of the danger of extinction must be changed for the common dolphin living off Israel’s coast. This definition is determined by International Union for Conservation of Nature. The researchers say that a stricter definition of the risk dolphins face will help convince decision makers and the public of the need to establish the reserve quickly. A year ago, researchers from Italy and Slovenia published an article in a scientific journal in which they called for the protection of the common dolphin, which is endangered almost everywhere in the Mediterranean.

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