While the tourists may not have started invading Mallorca yet, well apart from cyclists, jellyfish appear to have beaten them to it in some parts of the island. On Friday, the water near the beauty spot of Sa Forada between Valldemossa in Deya was busy with jelly fish putting hikers off having a refreshing dip in the glorious blue sea.
The Mediterranean has seen rising jellyfish sightings in recent summers, especially the stinging Pelagia noctiluca. Even with lifeguard warnings, stings often happen unexpectedly — particularly in smaller coves or offshore. The biggest problem all swimmers face is the growth of the jellyfish population in areas like Mallorca.
There have always been jellyfish in Mallorcan and Balearic waters, including the Portuguese man o’ war, but over the past few years it appears that they have become more invasive and little bays and calas have become full of them, in particular the small purple ones, and the main reason for this is over fishing. “We’ve fished all of the predators which would normally prey on jellyfish out of the sea, especially in the Western Mediterranean, and that is why jellyfish and their stings are becoming more common,” one expert told the Bulletin.
The Mediterranean Sea is home to a diverse array of jellyfish, ranging from common native species to harmful invasive ones. While most Mediterranean jellyfish are not lethal, several can deliver painful stings, particularly during the summer and autumn “blooms” when they aggregate near coasts.
Recent blooms have become more frequent and persistent due to several factors:
Climate Change: Warmer water temperatures favor jellyfish reproduction and survival.
Overfishing: The removal of natural predators like sea turtles and large fish (tuna, swordfish) allows jellyfish populations to explode.
Pollution: Nutrient runoff from agriculture can lead to plankton blooms, providing more food for jellyfish.
The most frequent encounters involve the following native and invasive species:
Mauve Stinger (Pelagia noctiluca): The most notorious stinging jellyfish in the Mediterranean. It is relatively small (about 10 cm) but has 16 long tentacles that deliver a very painful, burning sting.
Fried Egg Jellyfish (Cotylorhiza tuberculata): Known for its distinct yellow dome that resembles a fried egg. It is generally harmless or causes only mild itching, making it popular for curious swimmers.
Barrel Jellyfish (Rhizostoma pulmo): One of the largest species, reaching up to 60 cm (sometimes 1 meter) in diameter. It is whitish with a violet-blue edge and is generally mildly stinging, though it can cause skin irritation.
Moon Jellyfish (Aurelia aurita): Translucent and saucer-shaped with four horseshoe-shaped gonads visible through the top. Its sting is very weak and often unnoticed by humans unless it touches sensitive areas.
Nomad Jellyfish (Rhopilema nomadica): An invasive species from the Red Sea that has become dominant in the Eastern Mediterranean (Israel, Turkey, Greece). It is large and delivers a painful sting similar to a burn.
Portuguese Man o’ War (Physalia physalis): Occasionally found in the Mediterranean (primarily near the Strait of Gibraltar). While technically a colony of organisms, it is treated as a jellyfish and is extremely dangerous, with long tentacles that cause severe pain and systemic shock