Known as by-the-wind sailor (Velella velella), this small vessel is at the mercy of the wind, which sometimes blows little blue boats ashore by the millions.
Cousin to jellyfish and the Portuguese man o’ war, Velella is a carnivorous predator. Toxins in its stinging tentacles are deadly to its plankton prey but don’t pack enough punch to poison humans. A by-the-wind sailor is not a single creature. Rather, it is a colonial organism: a collection of hydroid polyps that clone themselves, build a buoyant boat with a stiff sail, and take on specialized functions of protection, feeding and reproduction. The individual polyps of a Velella colony are linked together by a digestive canal that allows them to share food. Each by-the-wind sailor is a busy world of polyps borne on a tiny boat across the wind-stirred seas.
The sex life of Velella is complicated. Reproductive polyps of a colony make tiny medusas--basically miniature jellyfish. Each medusa, after it leaves the colony and develops to sexual maturity, produces either eggs or sperm, which combine to create a larva. The larva grows into a new colony of cloned polyps, which produce more medusas to continue the cycle.
Velella that wash ashore are sometimes gobbled by hungry gulls. In the open ocean, by-the-wind sailors are preyed upon by a sea slug known as the blue dragon, and by a species of purple snail, which makes a bubble raft to stay afloat as it stalks its sailing prey. Ocean sunfish, which can grow to more than 2,000 pounds, rise toward the surface to sip Velella, and these colonial organisms less than 2 inches long become the flesh of the largest bony fish on the planet.
Cannon Beach, Oregon