Beaches along the U.S. West cost have seen an onslaught of millions of jellyfish-like creatures during the past month, turning shorelines purple with the marine animal known as velella, scientists say.
A distant relative of jellyfish, the deep blue/purple Velella velella, also known as "by-the-wind sailors," clusters offshore every spring but seldom washes ashore in the numbers seen in the last month, marine experts say.
The animals possess small crests running across their upper surface that act as sails, moving them along the ocean surface.
Unusual wind patterns this year may be the reason so many have washed ashore, says Jim Watanabe of Stanford University's Hopkins Marine Station in Pacific Grove, Calif.
"They go where the wind goes," he says.
They've been reportedly washing ashore on California coastlines off Monterey, Santa Cruz, San Francisco and in Humboldt County, and also in Oregon and Washington.
Steve Rumrill of the Oregon Department of Fish and Wildlife says he agrees wind is the likely culprit driving millions of the creatures ashore.
"This is a wind-driven event, and winds are unusual this year," he says.
Although similar to jellyfish, velella are in fact floating colonies of tiny creatures known as hydrozoans, Rumrill says.
Hundreds of them come together to form a shiny bluish-purple body about 2 or three inches long, giving the appearance of a single larger animal, he says.
Unlike jellyfish, velella cannot go underwater, depending on its trailing tentacles to stretch into the water to capture prey.
And although they look enough like jellyfish for most people to assume that's what they are, or that at least they're close relatives, that's not the case, Watanabe says.
"In terms of taxonomy," he says, "they are as different from jellyfish as mammals and birds would be among vertebrates."
Still, as marine creatures they can't survive being washed up on a beach if they remain there very long, Watanabe says.
"They've got to be in the water," he says. However, "If they get washed on shore and the next wave draws them back out, they are probably fine."
But if stranded, with no mechanism for holding onto water, they will dry out and die in an hour so, he explains.
Beachgoers should avoid touching or picking up the creatures, Rumrill cautions, because although they are not poisonous to most people they do possess a venom which can cause a stinging sensation in the eyes or mouth.
