Iestyn Morgan was swimming near Trefin beach when he noticed something strange underwater.
First came three tentacles. Then ten. Then twenty, spreading like a translucent curtain beneath the surface. The 21-year-old diver, a native of Pembrokeshire, Wales, realized that he was facing a lion’s mane jellyfish, Cyanea capillata, with an estimated total length of between 10 and 15 meters: almost the size of a bus. Morgan recorded everything with his camera and shared it on Instagram in late August.
The unsettling thing isn’t just the size. This species normally inhabits the cold waters of Scotland and rarely ventures so far south. Morgan, who has been documenting marine life for years, told the BBC that it was the first time he had seen one like it in Wales, and that lately he has also noticed fish typical of the warm waters of the Mediterranean swimming where they had never appeared before. To scientists, the sea is showing him something he shouldn’t be seeing.