Mediterranean Jellyfish Disappear Due to Extreme Heatwave

Jellyfish, a common nuisance for beachgoers, have largely vanished from Israel's Mediterranean coast this late summer. This unusual disappearance is attributed to an extreme heatwave, which caused water temperatures to rise significantly. Jellyfish do not thrive in very warm waters, and the early arrival of these stinging creatures in May and June, before the peak of the swimming season, contributed to their premature departure.

The most common jellyfish in Israel, the "Nomadic" jellyfish, originates from the Indian Ocean and Red Sea. Its life cycle begins as a polyp on the seabed. When water temperatures exceed 22 degrees Celsius (71.6 F), swarms of young jellyfish hatch and drift towards the shore. However, if the water warms beyond 28 degrees Celsius (82.4 F), they seek cooler, deeper waters.

The phenomenon of "stinging water," or "jellyfish soup," occurs when intense heat causes jellyfish bodies to decompose. This releases a transparent mucus containing stinging cells, known as nematocysts. Contact with these cells can cause a burning sensation, and in rare cases, may require immediate medical attention. Doctors advise against applying salt to wounds, as this can exacerbate the sting.

While Israelis complain about jellyfish during the summer, other parts of the world face more severe issues. Areas like the Chesapeake Bay in the US and parts of Florida have reported hundreds of thousands of jellyfish stings annually. Australia's Queensland coast is home to the deadly "sea wasp" and "Irukandji" jellyfish, which are nearly transparent and can be fatal within seconds, leading to restricted beach access and mandatory full-body wetsuits for entry into the water.