Jellyfish are those dangerous summer companions that can spoil a perfect day at the beach. Although everyone is aware that they must be avoided, it is important to know that the irritability of the bite varies according to the species.
That is why every summer, institutions or organizations explain what types of jellyfish exist and how to react when you see a specimen floating near bathers. It should be taken into account that bathing on beaches is increasingly prohibited due to the excessive presence of jellyfish.
The first of all is to know why these animals bite. Their stinging cells are called cnidocytes and they are used primarily for feeding and defense. They are present throughout the animal’s body, but are mainly concentrated along the tentacles. That is why you should not touch them, not even dead.
One of the best known and which was recently in the news due to its presence on the coast of Murcia and Alicante is what is known as ‘fried egg’ (Cotylorhiza tuberculat). Popularly named for its large orange central bulge, it is an endemic species to our seas and is not very stinging, according to a document from the Department of the Interior. In any case, it is recommended to avoid it.
A second well-known species is the blue akalefo (Rhizostoma pulmo). The umbrela (the upper part) is bell-shaped, bluish-white in color and edged with purple. It can reach 40 centimeters in diameter, which makes it one of the largest jellyfish on the Spanish Mediterranean coast. Its stinging capacity is greater than that of ‘fried egg’, so it must be avoided at all costs. In addition, it releases a mucus that contains stinging cells. That is why, even if it is not touched, there could be a dermatological reaction when in contact with the same water.
A third jellyfish that must be avoided at all costs is the luminescent or carnation jellyfish (Pelagia noctiluca). Pink in color, its bite produces a sensation of itching, intense pain, inflammation and reddening of the skin. It also causes hives and edema, as well as vesicles, papules, or scabs that may appear and remain. Other symptoms, although rare, can include nausea, vomiting, muscle cramps, and shortness of breath.
Native to the Atlantic, one jellyfish that has grabbed the headlines in recent years is the Portuguese man-of-war (Physalia physalis). Climate change has encouraged this species, along with others, to reach the Mediterranean coast. It is made up of a gas-filled, purple and translucent chamber surmounted by a candle, which makes it very characteristic.
The caravel sting is one of the most feared among bathers. Contact can cause stinging and intense pain and in some cases systemic reactions. A line of white papules and a red margin usually appear in the area of ??the bite. Systemic effects that may be observed include tremors, diarrhoea, vomiting and seizures. The venom of the stinging cells of this species has neurotoxic, cytotoxic, and cardiotoxic characteristics.
Along with the luminescent or caravel jellyfish, there are also species whose stings are more serious than those of the rest. This is the case of the radiant acalefo or compass jellyfish (Chrysaora hysoscella) and the cubomedusa or sea wasp (Carybdea marsupialis). In the first, its bite usually produces a sharp, stinging, stinging pain for the first 20 minutes after contact and usually subsides within the first two hours. In the second, the bite of this species is very painful, but the effects are short-lived. Reddish papules generally appear on the skin and in some exceptional cases muscle cramps, vomiting, tiredness and anxiety can be observed.
Another also very stinging and found in localized areas of the Catalan coast is the cross jellyfish (Olindias phosphorica). It is a dome-shaped, translucent umbrella hydromedusa up to 8 cm in diameter. It is surrounded by many short purple tentacles. It has four short, cross-shaped gonads that are maroon in color and fluorescent pigmentation visible at night.
