In a period of hours during a day a couple of weeks ago, 300 people on Barcelona’s bustling beaches were treated for stings, and 11 were taken to hospitals.

Immortal Invaders Infect World’s OceansThe Hydrozoan, a small predatory sea creature like a jellyfish but without all their well known exciting higher functions,...

Nowhere is the sting of these poorly understood invertebrates felt more sharply than the Mediterranean basin, where their exploding numbers have devastated native...