Let’s talk about pyrosomes! Often called sea pickles or sea squirts, pyrosomes are most commonly found in tropical waters, but stormy ocean conditions are known to bring the mysterious creatures as far north as Alaska.
As the ocean currents change with the seasons, beachcombers have been finding an abundance of pyrosomes along the high-tide line.
Pyrosoma atlanticum is the most observed species found along Oregon beaches are a rigid, bumpy, pinkish-gray tube about the size of a finger.
Throughout the world pyrosomes can range in size from a few centimeters to over 30 feet long, but the common Pyrosoma atlanticum reaches a maximum length of two feet. These totally tubular critters are actually known as a colonial tunicate, a mass of thousands of smaller organisms with a rigid notochord — a simplistic backbone.
Pyrosomes are actually colonies of multicelled animals called zooids. Thousands of cloned zooids create the cylinder-shaped, tube-like body and are connected by tissue that enable communication and coordinated behavior. To swim and feed, pyrosomes move their cilia (hair-like structures) together to draw in water and filter-feed on plankton.
After the plankton is caught on mucus the zooids expel the water in coordination to propel their tube-body through the sea.
Similar to other pelagic creatures (animals that live in the open ocean) pyrosomes migrate vertically and are capable of swimming a vertical distance of 2500 feet in one day.
Their scientific name pyrosoma roughly translates into a Greek word for “firebody” which references their ability to exhibit bioluminescence while alive. In general, the lifecycle and role of the pyrosome in the ocean food web remains a mystery, but some scientists have theorized that the bioluminescence is to attract plankton to eat.
Other observations have been made that pyrosomes seem to be successful when ocean conditions promote plankton blooms. Known predators include bony fish, dolphins and whales. While it is generally understood that pyrosomes do not pose a threat to humans, local experts suggest not letting pets eat pyrosomes when found on the beach!