This week in particular, but throughout summer noreasterly winds prevail on the east coast of Australia. With it they bring the scourge of swimmers, the bluebottle, aka portuguese man-o-war. These stinging jellyfish dangle metre long (sometimes more) threads from beneath their float, covered in stinging nematocysts that deliver a painful blow to any unsuspecting swimmer, or fish that it preys upon.
Whilst most people loathe them they do attract attention from elsewhere. Three different species of nudibranch feed on the bluebottles, clinging to the surface of the ocean following them with the wind. Their bodies turn blue as they ingest the nematocysts, which in turn provide protection for the nudibranch. These beautiful creatures look like aliens from another planet with their elaborate bodies.
Glaucus atlanticus
Fish of Cabbage Tree Bay Aquatic Reserve, Sydney 