Guide not to get lost in a sea of very varied species and with very different effects
They are organisms whose presence in the environment is necessary to maintain the balance between species. But obviously the jellyfish they are not welcome by bathers who want to take a dip on the beach. Every summer they appear on the Spanish coast, due to multiple factors. In this list, from the Ministry for Ecological Transition, we explain what they are the most frequent species on the coasts of Spainand the degree of danger represented by its sting, often stinging and sometimes even dangerous for humans.
Aguacuajada (Cotylorhiza tuberculata)
It is also known as ‘fried egg jellyfish’ precisely because of its characteristic appearance. It has the shape and color of a flattened umbrella, yellowish brown, with a little green and a prominent orange central bulge. It is usually between 20 and 35 centimeters in diameter.
It lives both in open waters and on the coast, especially in the latter. It is common throughout the Mediterranean, during the summer and autumn. Very abundant in the Mar Menor.
Its danger is low, because it has a limited capacity to produce hives, due to the short length of its tentacles and the low density of stinging cells. It does not go beyond causing mild skin irritation and itchiness.
Luminescent Jellyfish (Pelagia noctiluca)
It is one of the most frequent. It can measure more than 20 centimeters in diameter. It has 16 tentacles that, when unfolded, can reach more than 20 meters in length. The entire surface of its umbrella is covered with warts and has a characteristic reddish-pink color.
It is very frequent in open waters and approaches the coast dragged by the winds from the sea to the coast, especially during the summer. It is abundant in both the Atlantic Ocean and the Mediterranean Sea.
Its danger is high. It causes irritation and itching at the skin level and can even leave an open wound that can become infected. Due to its abundance and the length of its tentacles, the affected skin surface can be high and thus the effect of the poison could cause respiratory, cardiovascular and dermatological problems that can last for weeks or even months.
Bad water (Rhyzostoma pulmo)
Known as aguamala, aguaviva or acalefo azul, it is a large jellyfish (it can reach up to a meter in diameter in its umbrella), with a bell-shaped shape and beautiful violet decorations. It is a species that lives on the Mediterranean and Atlantic coasts and can be seen especially during the summer.
Contact with it is stinging, although it does not usually cause serious injuries, but even so, care should be taken: it is not necessary to have direct contact with it to receive a sting in the event that we find ourselves in closed waters where there are loose tentacle fragments in it. .
Aurelia aurita
This jellyfish is saucer-shaped with scalloped arms, and is distinguishable by four violet-colored, horseshoe-shaped reproductive organs in its center. Transparent color, speckled with blue-white. Limited. It is more abundant in coastal areas and lagoons such as the Mar Menor, but also in fjords and closed bays with contributions from continental waters, as well as lagoons and coastal waters with significant saline variations. Its bite is not very dangerous, although it can cause skin irritation.
compass jellyfish (Chrysaora hysoscella)
The Chrysaora hysoscella, known in Spain as compass jellyfish or radiated acalefo, is characterized by its yellow and orange tones, its striped pattern and its long tentacles, which can reach five meters in length. Its color is yellowish white and it has a characteristic radial design on the umbrella that is reminiscent of the drawing of 16 bars open to the outside. In some specimens this drawing may not be clearly distinguished.
Relatively frequent in the Mediterranean and Atlantic, where it sometimes forms swarms. Common in open waters, but can approach the coast dragged by currents, especially during the summer.
Its danger is “high”, according to the Ministry for Ecological Transition, and its bites cause itching and burning at first. Erythematous lesions and edema appear immediately afterwards, producing welts that may take time to disappear.
Portuguese man-of-war (Physalia physalis)
Technically, it is not a jellyfish, but rather a colony of polyps and belongs to the order Siphonophores. For this reason, its morphology is somewhat different, since its ‘head’ floats, unlike what happens with true jellyfish. It presents vivid intense blue and pink-violet colors, and despite the relatively small size of its floating part (about 30×10 cm in the largest specimens), its fine poisonous tentacles, difficult to see, can exceed 20 meters in length.
It is typical of temperate Atlantic waters, although it can sometimes be found occasionally in the Mediterranean. It moves at the mercy of surface currents and the wind.
Its danger is ‘very high’, according to the Ministry. Contact with its tentacles can have very serious consequences for people. The high concentration of nematocysts and their powerful venom with neurotoxic, cytotoxic and cardiotoxic properties can in some situations produce a neurogenic shock caused by intense pain, with the consequent danger of drowning. In any case, it can cause burning and severe pain, and skin lacerations as a result of intimate contact with the tentacles that become entangled and adhere in the attempt to get rid of them.
sailboat (velella velella)
This species is also not a true jellyfish, but a hydrozoan with a floating structure. It is small: the diameter of its disk ranges from 1 to 8 centimeters. It forms large swarms during winter and spring. Fortunately, it does not pose any kind of danger.
Aequorea forskalea
Transparent jellyfish in the form of a plate of about 30 centimeters with recognizable black patterns. It is common in the Atlantic, although it can also be seen occasionally in the Mediterranean, and sometimes it can be massively concentrated along coastal strips. Their number is increasing in Catalonia and the Balearic Islands. It does not bite, so it is not dangerous.
Box jellyfish (Carybdea marsupialis)
It is also known, apart from as a box jellyfish, as a sea hornet in the Mediterranean. With a cubic shape and long tentacles, it has a strange appearance, accentuated by its bioluminescence, with a bluish or whitish color. One of the most striking features is that they have a complex eye that allows them to react to moving objects and respond to changes in light.
Its sting is very serious and can represent a serious danger to human health, but since it usually inhabits relatively deep waters (below 20m) it does not usually cause incidents. They are very difficult to locate.
American ctenophore (Mnemiopsis leidyi)
It is an invasive species that is native to the Atlantic coasts of America. Its introduction took place in the Black Sea where it contributed to the collapse of numerous fisheries. From there it has spread to other areas, including the Mediterranean Sea. It was detected for the first time on the Spanish coast in the summer of 2009.
It is a small and strange-looking organism, with beautiful iridescence of colors. It does not have tentacles, but is formed by a bulb of about 10 centimeters in length. It gathers in large concentrations (up to 15,000 individuals per square meter). It does not produce any type of sting and, therefore, is not dangerous.
Original Ministry list: https://www.miteco.gob.es/es/costas/campanas/campana-medusas/tipos_medusas.aspx
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Environment section contact: [email protected]