Apr 30, 2024 - News

Velella velellas are back (those blue, jelly-looking things all over San Diego beaches)

A jellyfish-looking creature washed ashore near a pier.

A Velella vellela on the beach near Scripps Pier in La Jolla. Photo: Courtesy of UCSD Scripps Institution of Oceanography

San Diego beaches are awash with small, blue, jellyfish-resembling creatures known as Velella velellas.

Why it matters: Despite their appearance, Velella velellas aren't in the same group as jellyfish and are typically harmless to humans, per the UCSD Scripps Institution of Oceanography.

Between the lines: They're also called "by-the-wind sailors" because of a sail-like appendage on one side, which sits above the water, allowing wind to push them along.

  • Their seasonal movements are unpredictable, but they tend to reach our coast in large numbers in late spring or early autumn, based on wind patterns and food availability.
  • They're mostly seen on California and Oregon beaches.
Two Velella velellas, which look similar to jelly fish.
Two Velella velellas. Photo: Linsey Sala

Fun fact: Velella velellas reside deep in the winter, then transition to develop a sail and reach the surface when conditions provide for a lot of zooplankton activity, Linsey Sala, manager of the Scripps Pelagic Invertebrate Collection, told an institution publication.

  • While Velella velellas are on the surface, their tentacles trail underneath, feeding on the zooplankton.
  • They do have stinging cells that stun the zooplankton with a neurotoxin, but it's not strong enough to harm human skin.

What's next: We're in store for beach weather all week — so check out these creatures and send us your best photos.

  • We can confirm Coronado Beach was strewn with Velella velellas on Sunday, and Scripps has posted videos around Scripps Pier, as well.
A miccroscopic image of a Velella velella.
A microscopic image of a Velella velella. Photo: Anya Stajner

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