Aaaargh! Jellyfish! Everyone dreads the presence of jellyfish in the sea. It usually means no swimming or swimming at the risk of getting stung. But how much do we actually know about this strange jelly-like creature with tentacles? Understanding jellyfish is a good start to sharing the sea with them. Here are a few facts that are good to know.
Jellyfish don’t swim
Some jellyfish species can make pulsating movements to control their vertical position in the water column, but they can only sway along prevailing water currents and not oppose them. It’s good to know this because, unless you actually swim into one, a jellyfish cannot attack you. If you’re careful, you can be in the same space as a jellyfish and not get stung.
Jellyfish move together
Since jellyfish are dragged by currents, it is safe to assume that the current will drag a bunch of them in the same direction. Jellyfish swarms or blooms consist of large numbers of jellyfish aggregating in the direction of prevailing water currents. The direction of the wind usually determines the direction of water currents, so choose a beach that is opposite the direction the wind is blowing.
Jellyfish are on the increase
While some summers feel relatively jellyfish-free, others might experience an invasion. Warmer seas, due to climate change; increased nutrient concentrations in the water from fish farms; the waste of phosphates and nitrates; over fishing; and a decrease in predators such as sea turtles all contribute to increasing the numbers of jellyfish. Learn how to reduce your human impact on the marine environment, such as avoiding the use of plastic bags which turtles confuse for their food.
Jellyfish come in many shapes and colours
There are many species of jellyfish in the Mediterranean and recently, alien jellyfish species are coming from the warmer waters of the Indian and the Pacific Ocean through the Suez Canal. Some jellyfish are more dangerous than others so it is good to become familiar with the different species.
Not all jellyfish sting
Contrary to popular belief, only a small portion of the 200 known jellyfish species cause a sting and these are known as stingers. The sting comes from the tentacles, which contain stinging cells called nematocysts that contain a mild venom. Most jellyfish, however, do not sting at all!
Two types of jellyfish are most common in Malta
The most common jellyfish in the Mediterranean Sea are the mauve stinger (pelagia noctiluca) and the fried egg jellyfish (cotylorhiza tuberculata). The common fried egg jellyfish, which blooms at the end of summer (September-October), has no tentacles and does not sting at all; you can pick it up with both hands. The other common jellyfish, the Mauve Stinger, tends to catch a few unfortunate swimmers throughout a season.
Some jellyfish are very dangerous
Know how to recognise the more dangerous species so you can stay well away. The Box Jellyfish have a very painful sting that can be fatal to small children, the elderly or sickly people, so seek medical attention immediately in case of a sting. The Portuguese Man o’ War is technically not a jellyfish but also inflicts a very dangerous sting.
Jellyfish are edible
Right, you won’t find a specialty jellyfish dish in any Maltese fish restaurants, so that’s clear. However, jellyfish are popular for human consumption in some parts of the world, including China, Japan and Indonesia. Good to know, in case you travel to those countries and like to eat jelly.
What to do if you get stung
- Get out of the sea and onto dry land as a safety measure.
- Rinse with sea water - never use fresh water.
- If available, rinse with vinegar to neutralise the venom.
- Remove any tentacles with tweezers and rinse again.
- You can use a hydrocortisone cream or an oral antihistamine to relieve itching and swelling.
- If you have an open sore, clean it regularly and apply antibiotic ointment and a bandage.
- Immediately seek medical attention if the person displays signs of a severe allergic reaction, the sting covers more than half an arm or leg, or the sting is known to be from a Box Jellyfish.
That said, thousands of swimmers enjoy the Maltese shores, beaches and seas throughout a season quite unaffected by jellyfish. It’s good to know and be prepared but it’s even better to go ahead and have fun!