Jellyfish Season

Jellyfish season here in Israel is about to end, with the last part of June, the whole of July and sometimes the beginning of August being the peak months of their appearance in our Mediterranean waters and on our beaches. There are several types of jellyfish in our part of the Mediterranean, the nomad jellyfish being the most common one. They are beautiful creatures, especially when you get to watch them move in the water. Their sting is not dangerous but very unpleasant – it really hurts and often causes burn-like lesions.

In the 1970s and 80s swarms of nomad jellyfish (who are known to have developed already 500 million years ago) first arrived on the coasts of Israel and became an inseparable part of the summer, forcing Israelis to change their bathing habits accordingly.

According to a theory that is widely known in Israel, the nomad jellyfish invaded the Mediterranean Sea from the Red Sea after the opening of the Suez Canal in 1869. The jellies thrive in the Mediterranean thanks to their opportunistic behavior and the small number of natural enemies they encounter in the area.

Lately, young researchers in the field are voicing doubts regarding the invasion theory. One of these researchers is Dr. Zafrir Kuplik, coelenterate collection manager at the Steinhardt Museum of Natural History, Tel Aviv (coelenterates are a group of aquatic invertebrates including jellyfish), who says that theoretically the nomad jellyfish may have been here already for hundreds of years. He explains that the nomad has a very complex life cycle, existing in the form of microscopically small polyps in one of its first life phases. So it is possible that the nomad jellyfish polyps have always been here, and that due to the environmental changes that have taken place in the last 40 years they were able to develop into mature jellyfish. Also marine biologist Dr. Dor Edelist of the Haifa University wonders if maybe the opposite of the widespread belief is the case, that the nomad migrated from the Mediterranean to the Red Sea and not the other way round, since only in the Mediterranean Sea huge swarms of the nomad jellyfish can be found.

What we do know for sure, says Dr. Dror Angel, marine ecologist and researcher from the University of Haifa, is that the timing of their showing up and disappearing in/from our waters is greatly influenced by the water and outside temperatures. After a cold and very rainy winter for instance, chances are that the jellyfish will turn up later that year.

Could jellyfish help rid our waters of plastic waste? Together with international partners, Dr. Angel is working on a research project investigating the possibilities of using jellyfish mucus to trap and remove microplastic pollution from the oceans?
The international site of the project: GoJelly – A gelatinous solution to plastic pollution

Wouldn’t it be ironic if these simple creatures were to help save us from the mess we made on this planet.

1. They’re Brainless, They Terrorize Beachgoers and They May Be Able to Help Humanity
2. Video by Dr. Zafrir Kuplik about jellyfish in the eastern Mediterranean Sea (in Hebrew)


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