They’re obnoxious, but maybe jellyfish on Israel’s coast could benefit mankind?

For a creature that has no brain, looks like a glob of almost-invisible gelatin and is composed merely of a simple nervous system and a digestive system, jellyfish are very annoying to Israeli bathers and even clog up the Israel Electric Corporation’s coastal power plants that use Mediterranean Sea water to cool off their systems. 


And they have arrived now, as they always do, just when the summer holidays have begun and the beaches are full of adults and children. In fact, jellyfish are not anti-Semitic creatures keen on spoiling vacations but arrive en masse when water temperatures reach about 28 to 30 degrees Celsius and often when there is a full moon. If there is any consolation, after their visit to Israel’s coast, they usually float or swim north towards toward Syria and Turkey and westward to Greece and Cyprus. 


The most common type is called Rhopilema nomadica (nomad jellyfish), but they are native not to the Mediterranean Sea but to the Indian Ocean, which is quite far away. They reached the sea when the Suez Canal connected it and the Red Sea was opened up in 1869. It took years for the creatures to spread to Israel’s coast, however, and they were reportedly first sighted here in 1976. What took them so many years to come here? It may be, according to marine scientists, that environmental conditions evolved only in the last 45 years and made it possible for them to grow into adults. 


They lack a single large mouth so they can’t feed on fish – but they do compete with fish by consuming small creatures in the sea that fish also eat. 


Their stings are so annoying when they come in contact with swimmers that some Israeli beaches have even started displaying purple jellyfish-warning flags – though there is not much one can do to escape their protective venom if one goes into the water. 


In an effect to relieve the pain from the sting, some Israelis come to the beach with containers of urine out of the belief that this yellow liquid offers some relief, but it is not true. Neither does vinegar or salty water. Instead, people who are stung are advised to pour fresh drinking water on the area to minimize the pain. Fortunately, they are not life threatening and do not cause significant medical problems beyond skin rashes – they are just unpleasant. 


Although surprisingly little scientific research has been conducted on these floating pests, it is now believed that jellyfish have the potential to be beneficial – possibly to filter microplastics from the ocean, produce collagen for improving the skin, make biomarkers to monitor genes and using the stinging mechanism for improve the delivery of medications. It is the prestigious European Union that has invested funds in a project investing whether jellyfish mucous can “digest” microplastic wastes in the sea. 


Now, researchers from the Charney School of Marine Sciences at the University of Haifa are leading a study aiming at understanding the migratory patterns of jellyfish – whether they drift in the current or swim on their own. 


Observing them at sea, in the air, diving and in the lab, the Haifa scientists have been monitoring swarms of jellyfish some 400 meters from the shore, mainly off the coasts of of Ashkelon and Ashdod in the south and Acre in the north. So far, the swarms seem to be smaller than those observed in the past two years. 


However, the nomad jellyfish is the type best known for its burning stings, said Dr. Daniel Sher, who coordinates the University of Haifa research project with Prof. Tamar Lotan, Dr. Yoav Lahan and research student Noga Barak. 


The routes taken by the jellyfish swarms along the country’s shores are not yet known, and it is unclear whether the jellyfish are swept away by the currents or whether they control their location in space by swimming. This makes it difficult to prepare for the arrival of the jellyfish, for example at bathing beaches and other sites along the country’s shores such as power stations and desalination facilities.


Joining the University of Haifa team are researchers from the Israel Oceanographic and Limnological Research Institute in Eilat, including colleagues from Tel Aviv University and the Technion-Israel Institute of Technology in Haifa. After locating the swarms, they boarded the Mediterranean Explorer research ship owned by the voluntary organization Eco-Ocean and tracked their progress using gliders and even a tiny submarine that followed the jellyfish to the bottom of the sea. 


The team members are also studying how jellyfish affect their environment, for example by preying on plankton and releasing organic matter or toxins into the water. Finally, they are investigating the mechanism involving bacteria that live on the jellyfish to check whether the bacteria cause the jellyfish to disappear quite suddenly from the shores of the country when the weather cools down. 



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