Blue "By-the-wind sailor" jellyfish, otherwise known by their scientific name Velella velella, have been washing up on West Coast beaches—scientists say in the billions—over the last two months, with sightings reported as far north as Oregon and far south as San Diego.
"The numbers, if you extrapolate, are awe inspiring," said Kevin Raskoff, a professor of Biology at Monterey Peninsula College. "With some of my students we counted more than a thousand per meter," Raskoff said. "The numbers get astronomical pretty fast."
The first reported sighting of Velella velella on a California beach this summer happened in Humbolt county on July 13. The number of velellas seen on beaches has grown steadily since then.
In Santa Monica this week, visitors were perplexed by the hundreds of small blue jellyfish dotting the sand.
"I saw stuff around, I didn’t know they were jellyfish. Living in Vegas, we never had many chances to see that, " said tourist and student Julian Florres.
Even locals were scratching their heads at the sight.
“They’re beautiful blue, these circles with these clear fins that come up. I’ve never seen anything like it," said Andy Sway.
The jellyfish normally live far off the coast and it's not clear what has caused them to wash ashore, Raskoff said.
"The last time we saw something like this was eight or nine years ago. They do seem to be more driven by prevailing wind currents."
But even the nature of these creatures remains a mystery in many ways.
"It’s a very curious animal. It’s considered a colony, kind of like a coral head," Raskoff said. " If you were to remove one, it wouldn’t survive. It really kind of twists the mind around about what is the individual exactly, as opposed to what is a member of a colony. So it’s a bit of biology that has actually perplexed biologists for hundreds of years."
Raskoff advises taking precautions when dealing with all jellyfish. Even though the sting of the "By-the-wind sailor" is too weak to penetrate through human skin and reach a nerve, some people are especially sensitive to jellyfish stings. He compares it to a bee sting: what merely discomforts one person could cause serious pain to another.
"It’s just amazing to think, we have this huge mass of animals that we don’t know that much about. They normally live in solitude way off the coast, and then every now and then we see them, it makes for a pretty great show."
Anyone who sees a jellyfish can report the sighting to Jellywatch, a research organization dedicated to recording and monitoring the appearance of jellyfish and genetically related sea creatures all over the world.