ATHENS – Just in time for the coming summer tourism season as Greece hopes millions will pour in during the lingering COVID-19 pandemic is the phenomenon again of purple jellyfish in parts of the Aegean, who are big and bring a big sting too.

Marine experts said it’s because of warming waters and overfishing creating a proliferation of the jellyfish whose tentacles can catch unaware swimmers from 10 feet away.

“This is the second year that we have observed an outbreak of Pelagia Noctiluca in Greek waters,” Epaminondas Christou, Director of Research at the Oceanography Institute of the Hellenic Center for Marine Research (HCMR) told Kathimerini, using the Latin name for the specific type of jellyfish.

The jellyfish had been sighted in large numbers in the central and northern Aegean, but also further south and particularly in the Saronic Gulf near Athens, with residents on Aegina saying the problem was particularly acute.

Christou said the purple stinger is a pelagic species that reproduces in the open sea and drifts on the sea currents, reaching coasts and beaches. It is found across the Mediterranean, he added, though the “persistence of the phenomenon in Greek waters indicates that there may be a breeding site in the Aegean.”

“According to older cycles, outbreaks of this particular species appear every 10-12 years and last two to three years. It remains to be seen if the pattern will repeat itself or if it will last longer,” he said, also citing climate change as a reason.

“On the one hand, the rising sea temperature increases its reproduction rate. On the other, the reduction of pelagic fish, which feed on them, give the jellyfish ground to spread. The same is the case with the declining numbers of turtles, which are their main predator,” Christou told the paper.

He recommended that swimmers come prepared with a sting lotion or salve combining equal parts baking soda and water and wash off any tentacles clinging to the skin.

The purple jellyfish is orange-brown in adolescence and acquires a striking mauve or pink color in adulthood but has a bell diameter of only 3-12 centimeters (1.18-4.72 inches) but has those dangerous tentacles.