Asian moon jelly
Aurelia coerulea
By-the-wind Sailor
Velella velella
About
The by-the-wind sailor is not one animal but a colony, a small blue raft that drifts across the ocean surface powered only by the wind.
Also known as: purple sail, sail jellyfish
- Length
- 5 cm · max 8 cm
- Depth
- up to 1 m
Habitat
This animal lives on the surface of warm and temperate seas worldwide, floating at the boundary between air and water with its stiff sail above the surface and tentacles hanging about a centimetre below. Strong winds often blow large numbers ashore, causing mass strandings on beaches.
Behaviour
Each colony carries a small rigid sail that catches the wind, so it always drifts slightly off the wind's direction with no way to steer or swim against it. It is a colony of many small polyps working together, some that catch and share food, others that defend the colony. It feeds on plankton, caught with stinging tentacles that hang in the water below the float.
Did you know?
Each colony buds off thousands of tiny jellyfish just a millimetre wide, yet these young jellyfish are almost never found in the sea, so little is known about what happens to them after they leave.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
