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Jellyfish in the Mediterranean

Experts are warning of an increased presence of jellyfish along the coast of the Mediterranean this summer. Some information and what you can do about it.

Josep Maria Gili

Josep Maria Gili

Professor Josep Maria Gili from Barcelona’s Marine Research Institute “Instituto de Ciencias del Mar del CSIC de Barcelona” is a high-ranking expert on jellyfish and has studied them worldwide. He has during the past 18 years continuously studied environmental factors that controls the occurrence of jellyfish and he says with certainty that there will be more and more jellyfish each year.

The main reason for this is humen’s impact on the oceans. “Overfishing, pollution and climate change have contributed to the increasing number of jellyfish in the oceans“.

The most obvious reason is overfishing, because many fish and turtles have jellyfish as their natural diet. Besides, fish are competing with jellyfish about the same food (zooplankton). The reduced number of fish will therefore lead to an increasing number of jellyfish.

Increased water temperatures and lack of rain are other factors that also increase the number of jellyfish on the beaches. Last year, the recorded temperatures in Spain were higher than ever, including three separate heat waves. This year, meteorologists are predicting a drier and warmer summer than normal, but no heat waves are expected.

jellyfishJellyfish do not bite, but use stinging cells that are attached to tentacles and their poison is supposed to kill or paralyze their prey. By touching the nettle cells a lethal injection is being shot out by small arrow like threads that attach to the prey, or in our case the skin.

The presence of jellyfish on the beaches during the summer months in Spain goes in waves. They can  last as long as up to 15 days, but usually last for only three days at a time.

Professor Gilis advice to bathers is that “if there are jellyfish on the beach, you should use the swimming pool and then wait a day or two before returning to the beach.

What’s being done

Last year there were experiments with jellyfish nets both in Spain, Italy and Malta, a project which was called “The Jelly-Risk.” This was very successful, so this year we will see more of these nets at several locations along the Mediterranean.

Along the Spanish coast, there will be staff whose mission is to clean beaches from jellyfish. In some cases fishermen are being engaged to catch jellyfish.

There is also a mobile app (Info Medusa 2016) indicating the presence of jellyfish. This mobile app has been around for four years, but has been improved this summer. Besides notifying about the presence of jellyfish on beaches it informs also about the water temperature and provides information on how to prevent and treat jellyfish stings. The latest version has been downloaded 27,000 times and 6,000 users have posted comments on the situation at 107 beaches. The program is available for both iPhone and Android Play Store and App Store. It is also available at this link:

jellyfish-spainIf you’ve been burned by a jellyfish

Professor Gilis advice if you have been burned, is to leave the water immediately and find a lifeguard. If there are no lifeguards on the beach then wash the skin with salt waer. Never use fresh water. It’s a good idea to cool the wound with ice for five to ten minutes. You can also try to wet the wound with vinegar or baking soda dissolved in water (do not rub). Try to keep the wound antiseptic to avoid infections. If the pain does not subside, or if you feel unwell – seek medical advice.

Professor Gili also warns against the widespread myth about urinating on the wound. “This is completely wrong. It may be effective for certain fish bites, but never against jellyfish stings.”