‘Tons’ of electric-blue blobs blanket California beaches. What are they?
Thousands of bright blue, jellyfish-like sea creatures are washing up on beaches across California.
The critters — called velella velella or by-the-wind sailors — typically appear in the early spring, according to iNaturalist, an online platform for sharing biodiversity information.
What are the mysterious critters? Are they harmful to humans or pets?
Here’s what to know:
What are velella velella? What do they look like?
Although the transparent blue blobs resemble jellyfish, velella velella aren’t actually jellies, according to the National Park Service.
They’re hydrozoans — a species related to jellyfish, anemones and corals, the park service said.
The invertebrate, oval-shaped creatures typically measure 3 to 4 inches long, and have translucent, triangular sails.
These free-floating hydrozoans “live on the surface of the open ocean” and use their stinging tentacles to prey on plankton, UC Santa Barbara said. “ They are usually deep blue in color, but their most obvious feature is a small stiff sail that catches the wind and propels them over the surface of the sea.”
Velella velellas are left stranded on the beach when certain wind conditions blow them to the shoreline, UC Santa Barbara said.
Where have sea creatures been spotted in California?
Thousands of electric-blue blobs have been spotted on beaches across the Golden State, with sightings as far north as Del Notre County and as south as San Diego County, according to iNaturalist.
In late March, “unusual blue shapes started appearing along beaches in the San Francisco Bay Area,” The Pulse reported. “Within days, entire stretches of coastline were covered.”
The jellyfish-like creatures began washing up on Central Coast beaches in mid-April, The Tribune previously reported.
“Spring has sprung, which means velella velella, or by-the-wind sailors, start washing up on our shores,” the Visitor Alliance of Cayucos wrote
The same day, Reddit user Shell_Fly, posted a picture of velella vellalas strewn on the sand at a Ventura County spot.
“There are TONS washing ashore at Emma Wood State Beach,” the Reddit user wrote.
On April 20, Instagram user 805ology shared a photo of thousands of by-the-wind sailors on the shores in Goleta, captioning it “Hella Velella on 4.20.26.”
They’ve also been spotted on beaches in La Jolla, Pacific Beach and Coronado, San Diego station KUSI-TV reported.
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How long will by-the-wind sailors stay on the beach?
By-the-wind sailors most frequently turn up on California beaches during the spring or early summer months, the National Park Service said.
“As the velella dries out on the beach, it becomes brittle and transparent, looking like a cellophane candy wrapper,” before fully decomposing, the park service said.
Their dry, whitened husks “become food for shorebirds and tiny sand critters,” the Visitor Alliance of Cayucos said.
Are jellyfish-like blobs harmful to humans or pets?
Velella velella rarely pose a risk to humans, according to the National Park Service.
Dog owners should make sure that their pets don’t chomp on the dried-out jellies.
The poisonous sea creatures won’t permanently damage dogs who eat them, but they can cause nasty side effects, The Sacramento Bee reported in 2024.
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What should I do if my dog ate one?
By-the-wind sailors’ small stingers can upset a dog’s mouth and stomach if consumed, according to previous reporting from The Bee.
If you think your dog has bitten or ingested a velella, you need to act quickly, giving your dog “ice-cold water for a stinging mouth” and bland foods for an upset stomach, Dr. Brieana Sarvis, hospital director of San Diego Humane Society’s Escondido Campus, told ABC 10 in 2024.
If your dog is vomiting continuously, take your pet to the vet as soon as possible, The Bee reported.
This story was originally published April 23, 2026 at 11:13 AM with the headline "‘Tons’ of electric-blue blobs blanket California beaches. What are they?."
