Odd-Looking Blue Creatures Are Washing Up in Large Groups on California’s Beaches Once Again
Strandings of these jellyfish-like animals, sometimes called “by-the-wind sailors,” usually mean spring is coming
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California beachgoers have been shocked to find thousands of blue, jellyfish-like creatures coating the West Coast sands.
Del Dickson, who saw the animals on Bolinas Beach in Marin County while walking his dogs, tells the San Francisco Chronicle’s Nora Mishanec that from far away, they looked “like an oil slick” covering the shoreline. “There were rafts of them,” he adds. “It was really amazing.”
While their sheer numbers might seem ominous, Velella velella, also known as “by-the-wind sailors,” aren’t dangerous. In fact, their appearance usually means spring is on the way. According to the National Park Service, Velella are thin, oval-shaped blue or purple creatures that usually grow around three to four inches long, and they use their stinging blue tentacles to prey on plankton. The creatures are related to jellyfish, sea anemones and corals.
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But unlike jellyfish, which drift and swim in ocean currents, V. velella are at the mercy of the wind. Each one has a small, translucent, sail-shaped limb that pokes into the sky as its body floats on the surface of the ocean. Interestingly, the angle of the creature’s “sail” makes each specimen either right- or left-handed. Because of the orientation of Earth’s prevailing winds, the Northern Hemisphere usually has left-handed Velellas, while the Southern Hemisphere usually features right-handed ones, per the National Park Service.
Velellas typically wash ashore in Northern California in spring or early summer, because “in the spring is when we have upwelling,” explains Raphael Kudela, a marine scientist at University of California, Santa Cruz, to KQED’s Danielle Venton and Sarah Mohamad. “Upwelling brings lots of nutrients, and lots of nutrients bring phytoplankton and zooplankton.”
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Upwelling takes place when winds cause deep layers of cold, nutrient-rich water to rise toward the surface. The process sometimes concentrates Velellas into large groups, and changing wind patterns can sweep them ashore all together.
“They don’t wanna be on the beach particularly, but they end up there, because they can’t control where they go,” Kudela adds. When Velellas dry up, they lose their brilliant color and start to look like brittle cellophane candy wrappers, per the National Park Service.
Velellas aren’t a serious threat to humans, but last year Carolyn Belak, an aquatic ecologist at the environmental consulting firm H. T. Harvey & Associates, advised people not to touch them, since their small stingers could still irritate the skin, per SFGATE’s Ashley Harrell.
While the arrival of Velellas isn’t unusual, previous research has tentatively connected rising temperatures on the ocean’s surface with an increase in their strandings. “When we see signals coming from the ocean to the coast, we should pay attention,” Julia Parrish, a marine biologist at the University of Washington, told KQED’s Ezra David Romero in 2023. “The Velella velella is an early warning bell that we may be seeing some shifts.”
Nevertheless, the small, colorful creatures “provide a window of wonder and awe to the great ocean,” Jennifer Stock, an education specialist at NOAA’s Greater Farallones and Cordell Bank National Marine Sanctuaries, says to SFGATE’s Madilynne Medina, “and how much we know and don’t know about the largest habitat on the planet.”
