Marine invertebrates called pyrsomes are appearing in record numbers in areas where they had rarely been seen before.
Photograph by Steve Morey
The blooms have left scientists scratching their heads.
Photograph by Steve Morey
Pyrosomes create their own light and are also called “fire bodies.”
Photograph by Steve Morey
The pyrosomes have been gumming up nets and fishing lines.
Photograph by Moses P. Johnson
The animals require warm water and are most often seen in the tropics.
Photograph by Carver Mostardi, Alamy
They have a bumpy appearance on close inspection.
Photograph by Hilarie Sorensen
It’s unclear what impact the bloom is having on other wildlife.
Photograph by Hilarie Sorensen
After three years of unprecedented warm water along the U.S. West Coast, sea temperatures in 2017 had finally cooled. Fat shrimplike krill had returned and again were providing rich meals for salmon. Sea lions and other marine mammals were no longer washing ashore shriveled and starving. Things appeared to be getting back to normal.
Then they showed up.
Beginning this spring, millions of bizarre primitive-seeming jellyfish-like bioluminescent sea creatures—some more than two feet long—started gumming up research nets, glomming onto fishing hooks, and cascading onto beaches along the West Coast. These stubbly gelatinous animals called pyrosomes (each is technically a colony of other multi-celled animals called zooids) are cone-shaped tunicates normally found in the tropics, but they are spotted once in a while as far north as British Columbia. But this spring they started swarming the eastern Pacific in masses never before recorded, stretching from Oregon to the Gulf of Alaska.
“It’s really weird,” says Jennifer Fisher, a faculty research assistant with Oregon State University’s Hatfield Marine Science Center. “I’ve never seen anything like it.”
Neither has Rick Brodeur, a research biologist at the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center in Oregon. And he’s been studying jellies and other gelatinous creatures in the Pacific Northwest for 30 years.
“It’s just unbelievable how many of them there are,” Brodeur says.