By-the-Wind Sailors Washing Up on US West Coast Beaches

Velella velella
By-the-Wind-Sailors or Velella velella photo from Wikipedia

By-the wind sailors, also known by their scientific name Velella velella, have been washing up by the thousands along the West Coast of the United States. They have been found from Monterey, California all the way up the coast to Oregon.

What are Velella? They are distantly related to jellies as both are cnidarians. Velella are closely related to the Portuguese Man of War. They have a blue elliptical base and a transparent triangular “sail.” An individual is actually a hydroid polyp. A polyp is like the less recognizable stage in a jelly’s life when it is anchored to the sea floor, though Velella polyps are free-floating. In this polyp form, they spend their whole lives at the surface. Velella are at the mercy of the wind to get anywhere. They are found in warm and temperate oceans.

Velella eat by using their tentacles which hang beneath the surface. Like jellies, the tentacles have nematocysts, or stinging cells, to catch their food. These stinging cells are not dangerous to humans, though each person’s tolerance to their venom varies.

There are two forms of Velella. One has a left-to-right orientation of its sail, and the other form has a right-to-left orientation of its sail.

The Velella life cycle (like many “jelly-like” creatures) can be summarized as polyp-medusa-egg-planula-polyp. The polyp stage is the one written about in this post. The medusa is the free-floating stage, like any jelly you can think of. The eggs are microscopic and part of the plankton. Planula are the “free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species,” i.e. the fertilized egg.

Next time you are at the beach, look for these By-the-Wind Sailors!

Sources used: Univ. of Michigan animal diversity page

San Francisco Chronicle article “Beached blue wonders”

Wikipedia page on planula