Photo by Scott Sonnenberg (wikipedia)

The Portuguese Man O’ War (Physalia physalis), one of the world’s most poisonous “jellyfish”, has been spotted off the Andalusian coastline near Almeria and along the Costa del Sol between Cadiz and Malaga. This is the first time they have reached Spain’s coasts for ten years. Scientists have warned the creatures could soon arrive in waters around the Balearic Islands and the Catalan coast. The species is not a true jellyfish but but rather a siphonophore – a colony of four kinds of minute, highly modified individuals, which are specialized polyps and medusoids.

Their sting is 10 times stronger than an ordinary jellyfish. Wikipedia notes:

The stinging venom-filled nematocysts in the tentacles of the Portuguese Man O’ War can paralyze small fish and other prey. Detached tentacles and dead specimens (including those which wash up on shore) can sting just as painfully as the live creature in the water, and may remain potent for hours or even days after the death of the creature or the detachment of the tentacle.Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin which normally last about 2–3 days after the initial sting, the pain should subside after about 1 hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, more intense pain. A sting may lead to an allergic reaction. There can also be serious effects, including fever, shock, and interference with heart and lung action. There have even been deaths, although this is rare. Medical attention may be necessary, especially where pain persists or is intense, or there is an extreme reaction, or the rash worsens, or a feeling of overall illness develops, or a red streak develops between swollen lymph nodes and the sting, or if either area becomes red, warm and tender.

Treatment for Man O’ War stings elsewhere on the body involve washing the affected area with salt water and then applying ice to dull the pain. More here

“Climate change is changing the migration patterns of many creatures. If they establish themselves it would be very worrying because they really are very dangerous,” Xavier Pastor, the European director of the Oceana ecological campaigning group, told the Independent.Even dead or washed up on shore the creatures still pose a threat because their tentacles retain their poison.”The Portuguese Man O’ War hasn’t been seen in the Mediterranean for a decade, and its appearance off the Spanish coast could herald a process of colonisation, which has happened with other invading species,” Mr Pastor said. Read in The Daily Telegraph

The Portuguese Man O’ War (named caravela-portuguesa in Portuguese) is named for its air bladder, which looks similar to the triangular sails of the Portuguese ship (man-of-war) Caravela latina (two- or three-masted lateen-rigged ship caravel), of the 15th and 16th centuries. As can be seen in the photo. Photo (wikipedia)

See also last year: Portuguese man o’war threat in Cantabrian Sea

Striped dolphin in Almeria

El mar más sucio del mundo (El Pais)

I think we take that “sea” here means open sea, and so excludes bodies of water such as the inland Aral Sea.