If you walk on the beach in the spring and summer, you have a good chance of seeing jellyfish washed ashore. But how do jellyfish get to the beach? Can they still bite and what can you do against a jellyfish bite?
Don’t swim but pulse
Jellyfish are cnidarians, invertebrates with (poisonous) stinging cells. They have an umbrella-shaped body with tentacles and are found in all major seas and oceans. Strangely enough, they can’t swim. They move by pulsating movements that propels them and they let themselves be carried away by the current of the sea. Jellyfish prefer to live far from the coast, in the deep sea water.
east wind
Why do jellyfish still wash up on the beach? The wind plays an important role in this. If it is east wind (offshore wind), wind from land to the sea, an undertow is created. The top layer of water is then pushed away from land by the wind, while the undertow moves towards land. The jellyfish are in that undertow, which means that they wash up on the beach. The jellyfish season is from April to November.
Growing jellyfish population
In 2021, more jellyfish than ever before seem to wash ashore. The cause of the growing jellyfish population is climate change and overfishing. Due to warming, the sea is warmer and there is more plankton to be found. That they are precisely the factors in which the jellyfish thrives. In addition, the natural enemy of the jellyfish, herring, tuna and salmon, is disappearing due to overfishing.
Tentacles with poisonous substance
The tentacles of jellyfish are full of stinging cells containing a poisonous substance. And while it’s called a jellyfish bite, the jellyfish doesn’t literally bite. As soon as we come into contact with the tentacles, the jellyfish shoots a poisonous, irritating substance like harpoons. That is the substance that gives a stabbing pain and irritates the skin. Sometimes the arrows, cells, remain on the skin, but are still active. And even though a jellyfish lying on the beach dries out and dies within hours, its tentacles remain active long after.
Jellyfish don’t bite, they shoot
Not all jellyfish bite. Nevertheless, according to Julia van Beinum of the ANEMOON Foundation, it is by no means advisable to recommend any jellyfish. “The ear jellyfish and sea mushroom, for example, do not bite. The Compass jellyfish, especially the blue haired jellyfish and yellow haired jellyfish, are quite stinging. Southern jellyfish, such as the cubic jellyfish, are much more dangerous. The Australian sea wasp is notorious. But the Portuguese warship, which is actually an entire colony, can also be dangerous,” Van Beinum told the AD.
What can you do about a jellyfish bite?
In itself, a jellyfish bite is not dangerous, only if you are allergic. If you have been bitten, rinse the skin with sea water, not with ordinary tap water, which aggravates the complaints. If available, warm water (which is compatible with the skin). The heat breaks down the proteins of the venom. Are there still cells/tentacles on the skin? not to rub. Scrape them off the skin with tweezers or use a (bank) card. You can rub the skin with agents that help against itching after an insect bite. If you get complaints such as headache, vomiting and breathing problems, contact your doctor immediately. This could indicate an allergic reaction.
The website Kwallenradar.nl keeps a daily record of where most jellyfish are located on the Dutch coast.
(Source: AD, Kwallenradar.nl, Red Cross)
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