Rome, 20 July 2022 – Invasion of jellyfish in our seas for high temperatures. Since April, an inversion in front of Trieste of the Rhizostoma pulmo, also called lung of the sea, has been observed, the annoying pelagia noctiluca, much more stinging than the previous one, reported in the Tyrrhenian Sea, while large colonies of Salpa fusiformis, a transparent tunicate with a gelatinous consistency, have been sighted in the Adriatic. Up to the extreme case of the fearsome Portuguese Caravelspotted off the coast of Sicily, Sardinia and Calabria, all places where jellyfish have never been lacking.
But not all jellyfish are stinging, some are harmless, and others (rare in Italy) can even be deadly. Let’s see qwhat kind of jellyfish meet in the Mediterranean.
Rhizostoma pulmo
Rhizostoma Pulmo, or sea lung or barrel jellyfish, is a scifomedusa of the Rhizostomatidae family. Recognizable by the opalescent hemispherical hat, tending to transparent, with blue-violet fringed edges. The body is called the manubrium and is composed of eight extensions of curled and lumpy white-transparent fabric, from which eight elongated, frayed and semitransparent tentacles depart. It is the largest in the Mediterranean as it can reach 50-60 cm in diameter and 10 kg in weight. The tentacles are not particularly stinging for humans, and the irritation does not last long and vanishes leaving a slight itch.
Pelagia noctiluca
Perhaps everyone in Italy has been stung at least once by the tentacles of the luminous jellyfish, or Pelagia noctiluca, of the Pelagiidae family and very common in our seas (with invasions reported in 1992, 2003 and 2005). And it is difficult to forget because of the painful irritation it causes if the tentacles are touched. The unmistakable translucent brown-pink-violet color and the small size, about 10 cm, do not facilitate its identification by bathers: its 8 long retractable tentacles are very stinging and semi-transparent can even reach 2 meters. Experts advise to avoid scratching, but to wash away the poison by removing the tentacles from the skin with sea water and applying an astringent aluminum chloride gel to the skin. No to ammonia-based products or natural remedies such as urine, hot stones or sand: they risk increasing irritation.
Cotylorhiza Tuberculata
Cotylorhiza Tuberculata is also the most common in the Mediterranean Sea, with the highest concentration in the Adriatic. Also known as Mediterranean cassiopea, it is a scifomedusa of the Cepheidae family. In size it touches 30 cm in diameter with a recognizable white disc-shaped umbrella with a round and yellow hump in the center, which looks like a bull’s-eye egg. The edge is jagged between yellow and greenish. It is devoid of tentacles but has many oral arms that start from the four lobes of the mouth, many are thin and end with a blue or purple button. Cotylorhiza Tuberculata is harmless and non-irritating, only the most sensitive subjects can incur small discomfort on contact.
Carybdea marsupialis
On the contrary, the Carybdea marsupialis is very stinging, also known as Cubomedusa, it is encountered in shallow and sandy bottoms: it is an Atlantic species but increasingly widespread in the Mediterranean Sea. The name owes it to its almost cubic and transparent shape, 3 cm in size. It has 4 long stinging tentacles that reach a length of 30 cm, ten times the body. Underwater it can be identified thanks to the color of the transparent tentacles in the shape of red rings. Sore point is its poison that can cause serious burns and even endanger the life of the intoxicated, even if they are added to any allergies due to certain particles present in the protein set that makes up the poison. When you come into contact with quase jellyfish, the tentacles generally wrap around the limb of the victim: experts recommend removing it immediately and starting immediately to treat burns. The action of the poison can be reduced by exposing the stung part to strong heat sources such as sand or boiling water. Also try ammonia which like vinegar has soothing effects. In addition to being very painful, burns leave their mark on the skin for several weeks.
Aurelia Aurita
The Aurelia Aurita is one of the best known and most widespread: it has a perfectly spherical umbrella of a diaphanous and transparent white color, with four circular structures above its top, the gonads, which form a four-leaf clover-shaped structure, a characteristic that gives it the common name of the species. It is stinging with short and thin tentacles that descend from the edge of the umbrella, moreover it has four thicker arms that start from the center of the umbrella, in older individuals.
Chrysaora hysoscella
Chrysaora hysoscella or brown jellyfish belongs to the Pelagiidae family. Another nickname is medusa compass for the V-shaped decorations on the umbrella, and is present both in the Atlantic Ocean and in the Mediterranean Sea. It is not an exclusively coastal species, in fact it is easier to meet in the open sea. It can be found in aquariums as an ornament and is not very stinging: contact with the tentacles causes dermatitis with itching and burning, which occur within 20 minutes of contact.
Drymonema dalmatinum
Drymonema dalmatinum is the largest jellyfish in the Mediterranean: the umbrella can reach up to 2 meters in diameter. And it is very rare: after 10 years in the Upper Adriatic three specimens have been sighted. Drymonema dalmatinum is very stinging.
Physalia physalis
We close with the most dangerous Physalia physalis or Portuguese Caravella, which has made its appearance in recent years off the coast of Sicily, Sardinia and Calabria. It is a marine coelenterate and due to its appearance it is often mistaken for a jellyfish, but it is actually a siphonophore: it is not a single multicellular organism, but the aggregation of specialized individuals of four different types, called zooids, connected and physiologically integrated with each other. Its tentacles are capable of very painful and dangerous stings for humans: there are over ten types of venom that the nematocysts in the tentacles of the Portuguese caravel are full of, and each type of venom is characterized by its own color (for some not remedies are still known). Very dangerous detail: the 10 meter tentacles (but they can reach 50 meters) remain active and poisonous even after they have detached.
