School of Aquatic and Fishery Sciences

As their name suggests, by-the-wind sailor jellyfish know how to catch a breeze. Using a stiff, translucent sail propped an inch above the surface of the ocean, these teacup-sized organisms skim along the water dangling a fringe of delicate purple tentacles just below the surface to capture zooplankton and larval fish as they travel.

At the mercy of the wind, these jellies can wash ashore and strand — sometimes numbering in the trillions — on beaches around the world, including up and down the U.S. West Coast. And while these mass stranding events are hard to miss, very little actually is known about how or why they happen.

Now, thanks to 20 years of observations from thousands of citizen scientists, University of Washington researchers have discovered distinct patterns in the mass strandings of by-the-wind sailors, also called Velella velella. Specifically, large strandings happened simultaneously from the northwest tip of Washington south to the Mendocino coast in California, and in years when winters were warmer than usual. The results were published March 18 in the journal Marine Ecology Progress Series.

“Citizen scientists have collected the largest and longest dataset on mass strandings of this jelly in the world,” said senior author Julia Parrish, a professor in the UW School of Aquatic and Fishery Sciences and executive director of the Coastal Observation and Seabird Survey Team, known as COASST.

“This paper contributes to fundamental scientific knowledge of this organism in a way that traditional ‘mainstream’ marine science has been unable to do. Thousands of trained, dedicated observers are better than any satellite because they know their beach and can alert us if something is weird or unusual.”

COASST’s citizen scientists are trained to search for and identify carcasses of marine birds that have washed ashore at sites from northern California to the Arctic Circle. Participants are asked to record and submit photos of anything strange or different they see on their stretch of beach.

In 2019, program managers received an email from COASSTers in Oregon who had expected to see Velella on their beach based on past observations, but hadn’t. That prompted COASST scientists to comb the database — 23,265 surveys in total — to see if others had taken note of these jellies over the years. This “data-mining” returned 465 reports of Velella littering 293 beaches, often in more than one year.

“On the water, Velella are beautiful, fragile creatures. When they wash ashore, these jellies quickly dry to the consistency of potato chips. During a mass stranding it’s like walking on a crunchy carpet,” Parrish said. “So of course, COASSTers reported in. Suddenly, we realized we had the largest dataset about Velella velella anywhere in the world.”

In analyzing the citizen science observations, UW researchers discovered that most by-the-wind sailors wash ashore on West Coast beaches during the spring, when the winds shift and push the organisms to shore. However, their analysis also revealed truly massive stranding events in 2003-2005 and again in 2015-2019. During the later years, jelly carcasses covered more than 620 miles (1,000 kilometers) of continuous coastline, all within a single two-week window between mid-March to mid-April.

The second period corresponds with the timing of the long-lasting marine heat wave known as “the blob” — also to blame for the largest seabird die-off of common murres, as well as mass die-offs of Cassin’s auklets, sea lions and baleen whales.

The researchers hypothesized that warmer winters during these years allowed for populations of by-the-wind sailors to spike in the open ocean. Then, when the winds shifted in the spring, massive numbers of the jellies were swept to shore and stranded.

Put another way — and though many ultimately end up dying on beaches — the jellies appear to be “winners” during warmer periods, because they can amass more numbers in the ocean. There’s some evidence that warmer-than-average winters are also calmer and less wavy in the open ocean, allowing increasingly large Velella aggregations to persist, Parrish explained.

“This paper and our data really do suggest that in a warming world, we’re going to have more of these organisms — that is, the ecosystem itself is tipping in the direction of these jellies because they win in warmer conditions,” Parrish said. “A changing climate creates new winners and losers in every ecosystem. What’s scary is that we’re actually documenting that change.”

As warmer winters are expected to increase with climate change, these findings could have clear implications for this jelly population, as well as for the fish they eat and the beaches where they strand and die.

The paper’s lead author is Timothy Jones, a UW postdoctoral researcher in aquatic and fishery sciences. Hillary Burgess, now with the NOAA Office of Marine Debris, is a co-author.

This research was funded by Washington Sea Grant and National Science Foundation.

For more information, contact Parrish at jparrish@uw.edu.

Herring that spawn at different times of the year are genetically distinct from one another, according to a new paper published Feb 24th in the Proceedings of the Royal Society B.

The study, led by Eleni Petrou and Lorenz Hauser from the University of Washington School of Aquatic and Fishery Sciences, shows that populations of Pacific herring along the US west coast are genetically structured based on when they spawn and secondarily, where they spawn. These findings run counter to the common commercial fishing practices where herring are targeted and managed by area.

“Our findings show that Pacific herring populations may be at higher risk of unintentional overexploitation by fisheries,” said Petrou. “Most herring fisheries are spatially managed and do not account for genetically and demographically distinct populations occupying the same areas.”

Pacific herring (Clupea pallasii) are an extremely valuable commercial fishery as well as a cultural keystone species for coastal Indigenous communities. Large scale sac roe commercial fisheries for herring in British Columbia and Alaska often target the fish solely for their prized roe or eggs, which are sold to global markets. Traditional subsistence fishing practices by Coast Salish peoples and Alaska Natives take a more sustainable approach by first allowing the herring to return and spawn before harvesting the eggs from hemlock branches, kelp, and hair seaweed.

This research was done in collaboration with  Native American Tribes, Alaska Natives, and First Nations who, for generations, have been stewards of these herring fisheries that are an integral part of their cultural identity.

The research team partnered with the Suquamish and Puyallup Tribes in Washington, the Haida Nation and Heiltsuk Nation in BC, and the Sitka Tribe of Alaska, and management agencies (Washington Department of Fish and Wildlife, Department of Fisheries and Oceans Canada, NOAA) to design the sampling scheme and aid in collecting herring samples across the study’s large geographic area, from Washington state north to southwest Alaska. The added citizen science component was immensely beneficial in terms of gathering the samples needed to run the study and providing important historical context through Indigenous traditional ecological knowledge.

“Big declines in herring have been reported after heavy commercial fishing that was localized in a particular bay.” said Petrou. “Elders would tell us that there used to be fish in an area for as long as they could remember and then a large fleet came into the bay and took out 20,000 tons in one season, and they haven’t seen any spawning activity since.”

To supplement the modern herring samples and accounts, the team also analyzed ancient herring bones found at archeological sites in the traditional territories of the Suquamish Tribe and the Puyallup Tribe. These bone fragments were housed in a collection at the Burke Museum and donated for the study.

“We extracted the DNA from the ancient herring bones, and then we compared it to the modern samples to get a sense of which herring populations Coast Salish peoples depended on in the past,” said Petrou.

The results of the analysis show reproductive timing drives the population structure for Pacific herring. Further, these findings can be used to illuminate the life history of herring, both in the distant past and in more contemporary case studies.

The Cherry Point herring population of the northern Puget Sound was once the largest population in the area, supporting a small sac roe fishery before its collapse.

“In the 1970s, that population actually made up more than half of the total biomass in Puget Sound, and now it’s pretty much gone,” said Hauser, professor of aquatic and fisheries sciences and one of the paper’s co-authors. “What Petrou showed in her research is that the population is genetically very distinct from all the other populations, and now it has virtually disappeared.”

The Cherry Point population was petitioned to be listed on the Endangered Species Act twice, in 2000 and 2010, but NOAA believed that the differentiation between early and late spawners was not enough for them to be recognized as a distinct population segment. Currently, the population has yet to recover even though there is no longer any fishing pressure.

Incorporating new research toward the understanding of herring population dynamics can help influence management decisions by guiding sustainable practices and avoiding resource exploitation in a rapidly changing marine environment.

“Identifying the genetic basis of variation in reproductive timing in forage fish such as Pacific herring is important for predicting impacts of climate change, fishing, and other human activities on marine food webs,” Petrou said. Given the ecological, economic, and cultural significance of herring, our results demonstrate the importance of intraspecific genetic diversity on ecosystem processes now and in the future.”

UW co-authors include Petrou, Hauser, Carolyn Tarpey and Isadora Jiménez-Hidalgo. A full list of co-authors is available in the paper.

This research was funded by Washington Sea Grant, Natural Sciences and Engineering Research Council of Canada Strategic Partnership Grant, and a US National Science Foundation award.

For more information, contact Petrou at elpetrou@uw.edu or Hauser at lhauser@uw.edu.

Affiliate faculty Usha Varanasi recently published an article as part of the ICES Journal of Marine Science (ICES JMS) Food for Thought: Luminaries Collection, a curated collection of articles written by distinguished luminaries in the field of Marine Science.

In the article, “Casting a wide net and making the most of the catch”, she describes the “lessons learned and the people and principles that influenced six decades of professional endeavours from graduate schools to ascending, often unexpectedly, the science and management ladder in National Oceanic and Atmospheric Administration (NOAA) fisheries.” She goes on to detail her research in cetacean biosonar, the impacts of fossil fuel pollution on seafood and marine health, and her transition to management as director of the Northwest Fisheries Science Center.

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