The first time that you see Velella velella scattered across the beach, it can feel like an alien invasion is taking place. There’s no cause for alarm, these strange-looking sea creatures arrive by the thousands each spring. Word on the street is that they’ve taken over Ocean Beach in San Francisco as of this past Sunday, May 21, 2023.
Also known as “By-The-Wind Sailors,” these flat, oval-shaped hydroid polyps are related to the Portuguese Man o’ War and live in the open ocean, moving across the water using an upright triangular sail that catches the ocean breeze.
Velellas are born and live most of their life in the middle of the ocean, only drifting towards the shore during periods of strong onshore winds in the spring and early summer months. Large groups of Velella are often found stranded on shores along the West Coast from British Colombia to California as well as the west coasts of Ireland and England.
Similar to jellyfish, these creatures have little blue tentacles that hang down and are used to catch plankton and fish eggs. Unlike jellyfish, these tentacles are fairly harmless to humans. If you’re brave/curious enough to scoop one up just avoid touching your face, otherwise, you’ll probably be fine.
So keep an eye out for these “By-The-Wind Sailors.” A large group of them has already washed ashore in Point Reyes in April, and now they’ve arrived at Ocean Beach in San Francisco.