PORTLAND, Ore. (KOIN) — They’re bumpy, transparent and bioluminescent — and they’re washing ashore on Oregon’s beaches. 

Pyrosomes, or “sea pickles” as some people refer to them, are once again appearing along the Oregon coast. These cylindrical or cone-shaped colonies of creatures are certainly an odd thing to spot on a walk along the beach. 

“They don’t really look like your typical fish or sea star or dog or cat. They’re just these round tubes,” said Tiffany Boothe from the Seaside Aquarium. “It looks like plastic, for the most part.” 

A pyrosome is what’s known as a colonial tunicate, meaning it’s composed of several small organisms known as zooids. Each zooid is about the size of a grain of rice and has cilia to swim around. Most of the time, though, a pyrosome’s movement is determined by the current. 

Boothe said the current is the likely explanation for how these creatures that are usually found in tropical waters ended up on the Oregon coast. 

“We’ve been getting some really big storms, especially from the south. So the pyrosomes, while they are found off the Oregon coast in the summer months, usually in the winter we won’t see them unless we get these big, big winter storms,” she said. 

In Seaside, Boothe said they’ve only seen an occasional pyrosome wash ashore on the beach. But on the beaches in Florence, and the coastline south of there, there have been reports of hundreds of sea pickles on the beach. Bothe said through the winter, it’s possible they’ll appear more on the Northern Oregon coast. 

The Seaside Aquarium said Pyrosoma atlanticum is the most observed species found along Oregon beaches. Pyrosomes can reach a length of 60 feet, but Boothe said the colonies that wash ashore in Oregon are usually no more than 2 feet long. 

Boothe said she’s never seen a live pyrosome before and that the ones that wash ashore on the beach are usually dead before a human discovers them. So, throwing them back into the ocean won’t save them. 

However, she said it is safe for people to pick them up and feel them. They’re harmless, but marine experts don’t recommend allowing pets to eat them. Pyrosomes could make them sick. 

Boothe said not a lot is known about the life history of pyrosomes and scientists don’t know if they’re a major food source for any animal. In 2017, when there was an abundance of pyrosomes washing ashore on the Oregon and Washington coast, scientists feared fish and large sea mammals would consume them and fill up on something that doesn’t have much nutritional value. 

Pyrosomes themselves feed on microscopic plankton. 

Boothe encourages more people to head to the Southern Oregon coast to see the pyrosomes for themselves. She said they’re interesting animals and it’s an opportunity to take a closer look at them.