Researchers say sea pickles are adapting to the Pacific Northwest

July 20, 2018, University of Oregon
Portland, Oregon,-based muralist Esteban Camacho, the artist-in-residence during this summer's research cruise off the Pacific Northwest Coast, displays a large pyrosome found offshore, where the animals, known popularly as sea pickles, appear to be adapting to cool water after moving northward from warmer waters off the California coast. Credit: Mark Farley

Tubular colonial jellies known as pyrosomes that arrived in 2014 along North America's Pacific Northwest Coast appear to be adapting to cooler water and may become permanent residents.

That, a five-member research team concludes in a study in the journal Ecology, could mean a continued nuisance for regional fishing operations and changes to energy flows that could alter long-existing near-shore food webs.

"These animals may be able to survive in colder water than we previously thought possible, but what might really be contributing to their continued presence is that the food source off of our coast is right for them," said study co-author Kelly Sutherland, a at the University of Oregon.

UO graduate student Hilarie Sorensen, the study's other lead author, helped document the invasion by these "sea pickles," as pyrosomes are commonly called, during a research cruise in 2017. That prompted a deeper exploration.

Marine biologist Aaron Galloway was a third UO scientist on the research team. All three are with the Oregon Institute of Marine Biology at Charleston.

"The last few years have been relatively warm," said Sutherland, who also is with the UO's Clark Honors College and Institute of Ecology and Evolution. "The warmth on the surface tends to keep colder, denser, nutrient-rich water from reaching the surface; it's an oil-and-water kind of situation."

"These relatively nutrient-poor conditions lead to smaller prey particles that pyrosomes can capitalize on," Sorensen said. "This could be systemic of larger changes in the ecosystem."

Pyrosomes are made up of small, multicellular organisms, linked into a tunic to form a colony shaped like a tube. They are filter feeders that use cilia—tiny, hairlike projections—to draw plankton into their mucous filters. The ones seen off Oregon in 2017 ranged in size from about an inch to more than 2 feet long.

In their new paper, the researchers noted that pyrosomes—a name refers to their fiery bioluminescence—are "one of the least-studied planktonic grazers in spite of their widespread distribution and ecological significance."

Jessie Masterman, who will become a doctoral student at the Oregon Institute of Marine Biology on the University of Oregon's Charleston, Oregon, campus this fall, shows a double handful of sea pickles gathered this July on a research cruise. Credit: Kelly Sutherland

Researchers in Sutherland's lab have been involved in recent efforts to understand filter-feeders.

Until 2014, the creatures were common in warmer waters south of California's Cape Mendocino. They possibly then began moving up the coast into the Pacific Northwest as part of a multi-year "warm blob" that was followed by a strong El Nino in 2016, the researchers noted.

During a research cruise in February, pyrosomes were found amassed in large numbers at three separate locations, six, 15 and 28 miles offshore from Newport, Oregon, where the water temperature was about 50 degrees Fahrenheit. The jellies were found at the base of the surface layer at a depth of about 130 feet.

Fish, sea turtles and sea birds are among predators that have been seen feeding on the sea pickles along the Pacific Northwest coast. In the Gulf of Mexico and off the British Columbia coast, anemones, sea urchins and crabs have been observed eating them.

Their continuing presence and their capacity to reach bloom proportions, the researchers wrote, suggests that pyrosomes may be thriving in colder waters and could become more permanent residents in the California current, which extends from near Baja, California, to off southern British Columbia.

Summer 2017 was difficult for the Pacific Northwest fishing industry as both live and dying sea pickles were captured in large numbers by trawling nets, requiring time-consuming sorting and removal. Potentially, Sutherland said, some fishing operations could face relocation.

Large-scale aggregations of sea pickles can potentially restructure energy flows by their removal of photosynthetic plankton through consumption at higher levels of the ocean food web, subsequent fecal pellet production and sinking as they die off, the researchers noted in their conclusion.

Other study co-authors were Olivia Blondheim of Drew University in Madison, New Jersey, and Richard Brodeur of the National Oceanic and Atmospheric Administration's Northwest Fisheries Science Center at Oregon State University. Blondheim was supported by NOAA's Ernest F. Hollings Scholarship Program while a 2017 summer intern with Brodeur and Sutherland.

Sutherland's research group gathered pyrosomes during two research cruises this year—in February and July—as part of a National Science Foundation-funded project with Oregon State University to study zooplankton in the northern California Current, which runs along the west coast of the United States. OSU's team is led by Bob Cowen, director of the Hatfield Marine Science Center, and Su Sponaugle, a professor in the Department of Integrative Biology.

Explore further: West Coast waters returning to normal but salmon catches lagging

More information: Kelly R. Sutherland et al, Range expansion of tropical pyrosomes in the northeast Pacific Ocean, Ecology (2018). DOI: 10.1002/ecy.2429

Related Stories

Warm waters off West Coast has lingering effects for salmon

September 18, 2017

The mass of warm water known as "the blob" that heated up the North Pacific Ocean has dissipated, but scientists are still seeing the lingering effects of those unusually warm sea surface temperatures on Pacific Northwest ...

Warm Northwest waters draw spawning fish north

September 26, 2017

Unusually warm ocean conditions off the Pacific Northwest in the last few years led anchovies, sardines and hake to begin spawning in Northwest waters much earlier in the year and, for anchovy, longer than biologists have ...

Study shows how a tiny sea animal feeds itself and the ocean

November 16, 2017

Dime-sized ocean organisms thought to graze on any particles in their path are actually picky eaters, and their food-filtering process may be vital to how organic materials are distributed from surface waters to the ocean ...

Recommended for you

Semimetals are high conductors

March 18, 2019

Researchers in China and at UC Davis have measured high conductivity in very thin layers of niobium arsenide, a type of material called a Weyl semimetal. The material has about three times the conductivity of copper at room ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.