Joan Collins A plague of jellyfish which is affecting the whole of the western Mediterranean has already arrived in the Balearics. Large groups of them were seen in Cabrera and various points off the northern coast of Majorca during the weekend, according to experts from the Mediterranean Institute of Advanced Studies (IMEDEA) and from the Spanish Oceanography Institute. The biologist from IMEDEA, Damia Jaume, explained that there had been, a global explosion in all the Mediterranean, of jellyfish of the pelagia nocticula variety, from the south of Italy to the Balearics. This species is of medium danger, according to the biologist, although its sting is very painful and produces a rash. Some people who went to Cala Deya, Pollensa or Sa Dragonera over the weekend suffered the first stings and withdrew from the water. The pelagia nocticula is pink in colour, with reddish spots and, apparently, is very small as its body only measures 10 centimetres across. However, its tentacles (more difficult to see) are up to 10 metres long and it is these which sting bathers. According to the director of the Balearic Oceanographic Centre, Federico Alvarez, nature, is complex and it is not known why these things happen, and nor could it be predicted or controlled, although he considered that specialists should warn the authorities to minimise the impact of the arrival of this amount of jellyfish of the coast. Although the removal of jellyfish from the beaches is not the Balearic Government's job, the Balearic Ministry for the Environment did it last year and will do it again this summer, after the start of the Coastline Cleaning Plan this week which has 40 boats of the Pelican type collecting rubbish during the whole of the summer. The sting, which is produced by contact between the tentacles of the jellyfish and human skin, is caused by special cells on the tentacles which put a small blister filled with venom on the skin. The venom is then injected via a filament hidden in the blister. When a bather comes into contact with the tentacles of the jellyfish, there is an automatic reaction to get away from the tentacles, during which the tentacles can put several of these blisters in place, penetrating the victim's skin to let the poison in. The poison is common to all jellyfish of this type, together with other components which vary according to the species. The Balearic Oceanographic Centre recommends that the affected beaches be closed for two days because the jellyfish break up very easily and the water will be filled with stinging tentacles (although these cannot be seen at first glance). They also consider it necessary to rake the beach as the friction with the sand disperses the remaining jellyfish.