While we were descending along the “weight” to reach a submerged reef at a depth of 45 meters, we encountered “halfway” a luminous Jellyfish, the Pelagia noctiluca. Pelagia noctiluca Medusa luminosa Medusa viola intotheblue.it
The “weight” is nothing more than a weight connected to the diving ball, which is launched from the boat to signal the dive site and through which one descends to reach the bottom.
During this descent which is rather fast, unlike the ascent, marine species such as jellyfish, ctenophores, or pelagic fishes that live in the open sea are often encountered. In this case we encountered the Pelagia noctiluca, luminous jellyfish or purple jellyfish. It is one of the most common jellyfish in the Mediterranean Sea, and has the distinction of being one of the most dangerous. In addition to the main tentacles, it has retractable tentacles which can be up to two meters long and which are difficult to see even with the mask.
The jellyfish itself is practically semi-transparent, and is the one that causes the painful and annoying irritations even if only touched.
The luminous jellyfish (Pelagia noctiluca), is a jellyfish of the Pelagiidae family.
Distribution and habitat
It is common in the Mediterranean Sea and the eastern Atlantic Ocean up to the North Sea; it is known for its abundance in our seas in some periods and for the painful irritations it causes if touched. It is a pelagic species, but in the autumn and spring period it approaches the coast.
Brown-pink or pink-violet umbrella of about 10 centimeters in diameter, translucent, composed of 16 lobes from which 8 long retractable, very stinging and semi-transparent tentacles start, which start from the edges and can extend up to 2 meters. The oral arms, the same color as the umbrella, are up to about 30 centimeters long. The specific noctiluca epithet derives from the green iridescence of which it is endowed.
Supply. It feeds on plankton and small fish that it captures through the tentacles equipped with stinging nematocysts.
P. noctiluca is one of the jellyfishes that do not go through the polypoid stage during maturation. The adults are of separate sexes: the female lays her eggs in the sea, which are fertilized by the spermatozoa of the males. The planula is born from the zygote, a larva endowed with cilia for movement and which disperses at the planktonic level. However, it does not go through the scifistoma stage, anchoring itself to the ground, but divides directly into ephira, a young jellyfish that will then grow to form the adult jellyfish.