CBC Canada is reporting that millions of the sea creatures have been spotted off the coast of British Columbia this year, far more than was seen in the past two years when they first appeared. Vancouver Island-based fisherman Matt Stabler says the pyrosomes — pimply, tube-like animals — were so thick he and his crew had to move to different fishing spots more than once to avoid them.
Canadian scientists don’t know too much about pyrosomes because they are not normally seen off Canada’s coastline. But everyone is quickly learning the creatures are normally found in the warmer tropics and they can grow up to 10 meters (33 feet) in length.
“There are pictures of people swimming up to these, riding on them as a diver, sticking their head in the opening,” said Moira Galbraith, a zooplankton taxonomist at the Institute of Ocean Sciences in Sidney, B.C.
Description Channel Islands, California.
What are pyrosomes?
While coming across a 10-meter pyrosome would be scary, most of the sea creatures found off BC’s coast have been more in the range of eight to 60 centimeters (3.0 to 24 inches) in length. Pyrosomes belong to the genus Pyrosoma and are planktonic, bioluminescent cylindrical or cone-shaped colonies made up of hundreds of thousands of individuals, known as zooids.
So the creatures being seen in B.C. are actually “colonies.” Being planktonic, and this means their movements are largely controlled by currents, tides and waves, gives us a clue to how they reached the Pacific Northwest. They are normally found in the upper layers of the open ocean in warm seas.
The odd creatures remain plump and juicy-looking while in the water but become flat as a pancake after being on dry land for a few hours. But it is the sheer numbers of them that have researchers baffled. A central Oregon research team gathered 60,000 individual pyrosomes in around five minutes this year, using a trawling net while trying to find a rare fish they were researching.
Ric Brodeur of the Northwest Fisheries Science Center’s research station in Newport, Oregon has worked off the Oregon Coast since the 1980s and had never seen a pyrosome before 2014. “We’re trying to collect as much information as we can to try to understand what is happening, and why.”
Pyrosome numbers in the Northern California Current – which encompasses Northern California, Oregon, and Washington – increased in 2015 and again in 2016. However, the unprecedented numbers of them this year is puzzling. This year, for the first time, the pyrosome colonies have reached southeastern Alaska.
Scientists in B.C. and the U.S. have several questions they are pursuing – the pyrosome’s feeding behavior, the environmental variables the affect their numbers and the impact on the marine food web. The last question is particularly important because the pyrosomes eat zooplankton, which also supports populations of shrimp, crab, mollusks and other filter feeders.
One of my Digital Journal readers in Canada messaged me, wondering if the strange sea creatures were poisonous and more to the point – Were they edible? Pyrosoma are not dangerous or toxic, however, seals and some whales have been known to chow down on them. As for humans? Maybe my reader will let us know.
