SAN DIEGO – Thousands of blue jellyfish-like creatures have been spotted on Southern California beaches in the last few weeks – from Los Angeles to San Diego.

These blueish, purple creatures known as Velella velella, or By-the-Wind sailors, have been captured dotting the shoreline in piles for the first time in years, amazing scientists and beachgoers alike.

“They’re kind of what I would consider an ephemeral species – a little bit rare and exciting to come across,” Anya Stajner, a PHD student at the Scripps Institution of Oceanography, told Stajner has studied the velella velellas extensively, in addition to kinds of zooplankton. 

“Sometimes you’ll find them in large amounts, and sometimes, you won’t find them at all,” she continued.

Velella velella are known as a colonial hydroid, which is a type of species similar to the Portuguese Man O’War. While they have a jelly-like appearance, they are not closely related to the jellyfish.

Their bodies look like “deflated balloons” that float along the water’s surface, with a kind of horny structure that sticks up creating an almost sail – hence the nickname “By-the-Wind sailor.”

“Because they live at this air and water interface, they pretty much sit exactly at the surface of the water,” Stajner said. “They just go where the wind blows them. And that’s actually why they end up on our shores sometimes … they get pushed by a strong breeze that they can’t escape.”

They also have a sort of tentacle, according to Stajner, that allows them to passively feed on whatever is beneath them as they float with the tide and wind – everything from algae and zooplankton to larval fish. 

Meanwhile, their gorgeous blue color is working to protect them from the sun’s UV rays – thwarting sunburns from just below the surface.

The last time that the Velella velella were spotted on the San Diego shoreline in the thousands was back in 2015, according to Stajner. Since they move with the wind, it’s hard to say when they’re going to go back into the ocean with the waves.

“It’s kind of funny, Velella velellas are sort of like San Diegans,” Stajner laughed. “They spend a lot of their time in the sun and they go wherever the breeze blows them.”

Despite their unpredictability, she said that it’s likely that this year’s particularly wet winter created the ideal conditions for the major migration beachgoers are seeing. 

“Potentially, we’ve had the perfect amount of wind and storms and food in the water for these Velella velellas to be washing up on shore,” Stajner said.

So far, the Velella velella have been spotted at Torrey Pines, Mission Beach, Coronado, Oceanside and Carlsbad. Here are some pictures of the By-the-Wind sailors on San Diego beaches:

  • Hundreds of Velella velellas, or By-the-Wind sailors, on the beach in Coronado. (Courtesy of Coronado Lifeguards)
  • Image of a Velella velella, or By-the-Wind sailor, on the shore in Mission Beach. (Courtesy of Adam Hatter)
  • Hundreds of Velella velellas, or By-the-Wind sailors, on the beach in Coronado. (Courtesy of Coronado Lifeguards)
  • A close-up image of a Velella velella, or By-the-Wind sailor, on the beach in Coronado. (Courtesy of Coronado Lifeguards)

For anyone who might come across a few By-the-Wind sailors, Stajner said it is best to stay away and admire the creatures from afar, as to not injure or disturb them. They do have stinging cells, however, are not considered dangerous to humans by scientists.