Science and TechAnimals and Insects


'Blue blob' creatures once again washing up on California's shore

These blue blobs, resembling jellyfish, wash up on the West Coast from time to time. For most humans, they are harmless, scientists say.
Velella velella washes up on a beach.
Posted at 2:24 PM, Apr 09, 2024

Bizarre-looking blue blob creatures are once again washing up on California's beaches, but scientists have said they are usually harmless to humans. 

The blobs are known as velella velella, or "by-the-wind sailors." According to UC San Diego’s Scripps Institution of Oceanography, they have been in the scientific record since 1758. They also tend to wash onto the coasts of Oregon and Washington. 

They have an appearance similar to jellyfish but are a different species. They get their name because of the sail-like features on their body. 

According to UC San Diego researchers, they are moved by water currents and wind, causing them to wash onshore. 

"They have a pretty complex life history. There are additional stages where they will reside in the deep sea during the wintertime. Then, when conditions are such that they support a lot of zooplankton activity, like we see here in the spring, they transition to the stage with the sail, and they make an excursion from the deep sea up to the surface,” Scripps Institution of Oceanography pelagic invertebrate collection manager Linsey Sala said in a university feature on the creatures."That's when we start to see them in their feeding stage, with their tentacles trailing underneath them just below the surface."

What is that? Mysterious carcass washes ashore on Lake Michigan
File photo shows the shore of Lake Michigan.

What is that? Mysterious carcass washes ashore on Lake Michigan

Shelia Schmidt has lived in Grand Haven, Michigan, for a while now, but what she saw Wednesday marked a first for her.


In late March, Madison McKay, a research fellow at Moss Landing Marine Laboratories, noted on a TikTok video that the velella velella started washing onto shore. Her TikTok video showed thousands of them on the sand. 

McKay said that they do have stingers, but they are normally benign to most humans, adding that some people react differently. 

"When they wash up, they start out a bright blue color, but then leach out all their pigment," she said. "After a while, they are almost completely transparent as all their tissues disintegrate."