What Are Those Blue, Tentacled Creatures On Ocean Beach?

Velella by-the-wind sailor

By-the-wind sailors have been washing up on Ocean Beach and other local beaches in recent weeks. Known to science as Velella velella, they look something like small jellyfish but actually are colonies of many individual organisms and not closely related to jellyfish. Photo: Tom Prete / Ocean Beach Bulletin

They’re a bit hard to believe, the first time you see them: brilliantly blue, squishy, tentacled creatures cast up from the sea onto the beach.

On Ocean Beach, where so much of the natural environment wears shades of gray or brown or tan, they stand out like some sort of colorful, exotic tropical fruit or alien visitor from space. Maybe the strangest thing about them, though, is that their appearance on local beaches is perfectly normal.

Commonly known as by-the-wind sailors, scientists call the palm-sized creatures Velella velella. And although they look a little like jellyfish, California Academy of Sciences scientist Rich Mooi says, they’re not closely related and aren’t even single organisms as jellyfish are.

Velella is, in spite of its remarkable appearance as a working individual, actually a COLONY of individuals all of which work together to make up a kind of ‘superorganism,’” he wrote in an email to the Ocean Beach Bulletin.

Mooi, the Academy of Sciences’ curator of echinoderms, explained that by-the-wind sailors normally live out in the open ocean with their blue, tentacle-like appendages hanging down into the water to collect food and a sail-like crest projecting above the surface. When the wind blows it pushes the animals along by this sail, sometimes pushing them toward land where they accumulate near the edge of the water.

Most of the time, when Velella show up at Ocean Beach, it’s in the springtime when winds usually are strongest.

“It’s a little unusual to see them washing up in such numbers this late in the summer,” Mooi wrote.  “But that is the ONLY unusual thing about these strandings. They are common, happen to a certain degree pretty much every year, and have been happening for a long time, probably even long before there were humans here to notice it.”

Not only is it common for Velella to wash up on Bay Area beaches, but it’s also normal for them to land on the shores of the Pacific Northwest as well as Atlantic Ocean locations including New England and the British Isles, according to Mooi.

Mooi told the Bulletin that by-the-wind sailors are harmless and there’s no reason for beachgoers to be concerned about contact with them — within reason.

Velella is completely harmless,” he wrote. “But don’t eat them. I would never recommend that. Maybe don’t let your dog eat them, either.”

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