Bioluminescent, jelly-like sea creatures known as pyrosomes have left their natural habitat to swarm to the West Coast of the U.S.
Sea Pickles Ruler

University of Oregon

Reuters reports that huge numbers of jelly-like sea creatures have swarmed the waters of the West Coast.

Scientists and fishermen alike have witnessed enormous schools of these creatures, known as pyrosomes, off the coasts of California, Oregon, Washington, and even Alaska.

Pyrosomes are usually found in the tropical waters of the central Pacific Ocean, but have somehow now found their way to the cold waters of the West Coast.

Although most pyrosomes are only a couple of centimeters or inches in length, they are known to occasionally grow up to one or two feet. Their name, which comes from the Greek word meaning “fire body,” refers to their bioluminescence, which allows them to glow in the dark. They are also known colloquially as “sea pickles” due to their shape.

Rather than being a single entity, a pyrosome is actually a colony of tiny multicellular organisms called zooids, similar to the colony of polyps that form corals. Unlike corals, though, pyrosomes do not have a rigid structure binding them together, and instead form into a small, jelly-like substance with the consistency of a gummy bear.

These pickle-shaped creatures feed on plankton, and it is theorized that they either came to the U.S. Pacific Coast due to rising sea temperature or a shift in their food supply.

Either way, this is a new phenomenon, with the first pyrosome being seen off the West Coast of the U.S. only as recently as 2012. And the enormous current bloom of pyrosomes there now is entirely unprecedented for the area.

Even though pyrosomes are harmless, the sheer number of them is worrying to scientists and fishermen. The creature once known as “the unicorn of the sea” for its elusive nature, is now so numerous off U.S. coasts that a recent research expedition pulled in 60,000 of them in just five minutes.

Fishermen worry about the animals clogging up their engines and fishing nets, and scientists worry that a mass die-off of the creatures could poison the surrounding water.


Next, check out this glow-in-the-dark Shark discovered by scientists. Then, see another time that sea creatures flooded the California coast.

Gabe Paoletti
Gabe is a New York City-based writer and an Editorial Intern at All That Is Interesting.
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