European green crabs feast on shellfish, destroy marsh habitats by burrowing in the mud and obliterate valuable seagrass beds. The invasive species also reproduces quickly, making it a nightmare for wildlife managers seeking to control its spread in Washington’s marine waters.

Last month, Gov. Jay Inslee issued an in response to more than as well as dramatic increases in crab populations on Washington’s outer coast and other locations in Puget Sound in recent years.

As the green crab invasion in the state worsens, a new analysis method developed by 91Ě˝»¨ and Washington Sea Grant scientists could help contain future invasions and prevent new outbreaks using water testing and genetic analysis. The , published online Feb. 6 in the journal Ecological Applications, show that the DNA-based technique works as well in detecting the presence of green crabs as setting traps to catch the live animals, which is a more laborious process. Results suggest these two methods could complement each other as approaches to learn where the species’ range is expanding.

The new method relies on genetic material in the environment, known as eDNA, that is found in the water after organisms move through. Scientists can collect a bottle of water from a location, extract DNA from the water and discern which species were present recently in that area.

“We have limited resources to be able to combat this problem, and it’s important to think about how to allocate those resources efficiently and effectively,” said lead author , who completed the work as a master’s student in the 91Ě˝»¨School of Marine and Environmental Affairs. “Knowing the best situations for using eDNA to detect invasive green crabs is important, and that’s what our study tried to tackle.”

The research team relied on data collected over three months in 2020 from green crab traps in 20 locations throughout Puget Sound and the outer coast. Trapping at these locations was done by a large number of partners participating in statewide efforts to monitor and control European green crab, including multiple tribes, Washington Department of Fish and Wildlife — the state lead for green crab management — Washington Sea Grant’s , and other state and federal agencies.

For this study, the researchers visited each location and collected water samples, then ran genetic analyses to detect both the presence and quantity of European green crab in each location. In this way they could validate the eDNA data with the actual presence and numbers of crabs. They found that using eDNA to detect the presence and abundance of the species was as sensitive as trapping and counting live crabs.

This is significant, the researchers said, because eDNA as a detection method is new, and it hasn’t always been clear how to interpret eDNA detections in past scenarios. This study shows how conventional monitoring methods — in this case, trapping and counting crabs — can be combined with eDNA techniques to more effectively find and control invasive species outbreaks.

“Here’s a really well-validated example of how to use eDNA in the real world. To me that’s really exciting,” said co-author , a 91Ě˝»¨associate professor in the School of Marine and Environmental Affairs. “There are lots of invasive species, and many imperiled and endangered species that are hard to monitor, so this is one significant way forward on all of those fronts.”

The study also evaluates when eDNA would add value in monitoring for invasive crabs, and when conventional trapping and counting still make the most sense. For example, taking water samples and testing for green crab DNA in remote locations — or in areas where outbreaks haven’t yet been identified — could save time and resources instead of deploying traps. Alternatively, eDNA probably wouldn’t be helpful in locations where large numbers of green crabs are already living and where community scientists and managers are already trapping and controlling those populations, the researchers explained.

“From a management perspective, the value of this tool just really comes to life in places that are more remote or have a lot of shoreline to cover, like Alaska, where green crabs haven’t yet been detected,” said co-author , a marine ecologist who leads the Washington Sea Grant Crab Team. “I see eDNA as another tool in the toolkit, and we can imagine scenarios where it can be used alongside trapping, especially as an early detection method.”

Finding these crabs soon after they have occupied a new location is important for controlling the population and protecting native habitats. Managers could get ahead of new invasions by testing water from multiple locations, and then follow up with more water testing, on-the-ground monitoring and trapping if green crab DNA is detected.

The paper identified green crab DNA in one location where the species hasn’t yet been captured, near Vashon Island. The research team followed up a year later with intensive trapping and retested the water; no green crabs or additional green crab DNA were found. The researchers think the earlier positive sample likely was picking up green crab larvae, which weren’t present in that location a year later. Notably, the effort represented an important test case for how eDNA and traditional trapping can be implemented together for green crab management.

“The reason we pursued this project in the beginning is that early detection of green crabs is difficult — it’s like finding a needle in a haystack,” said co-author , a 91Ě˝»¨associate teaching professor in environmental studies and aquatic and fishery sciences and the 91Ě˝»¨principal investigator for Crab Team research. “So if adding eDNA to our toolkit helps us detect those needles, then that’s great to have at our disposal.”

of the Cooperative Institute for Climate, Ocean and Ecosystem Studies is an additional co-author. This research was funded by Washington Sea Grant.

Contact the co-authors for more information. Contact info and expertise listed below:

• Abigail Keller (lead author, eDNA, European green crab): g.keller1@gmail.com
• Ryan Kelly (eDNA): rpkelly@uw.edu
• Emily Grason (European green crab; Crab Team efforts): egrason@uw.edu
• Sean McDonald (European green crab; Crab Team efforts): psean@uw.edu
• Chase Gunnell, WDFW communications (policy and state funding questions related to green crabs): gunnell@dfw.wa.gov or 360-704-0258 (cell)

Grant number: NOAA Award No. NA18OAR4170095

Andrew Meltzoff honored by the Association for Psychological Science

, 91Ě˝»¨professor of psychology and co-director of the UW-based Institute for Learning & Brain Sciences, has been recognized by the Association for Psychological Science with a for 2020.

Meltzoff was one of four this year to receive the , which is given to members of the association, or APS, to honor “their lifetime of significant intellectual contributions to the basic science of psychology.”

The association praised Meltzoff, saying his “landmark studies in infant development helped reconfigure our understanding of preverbal cognition.

“Meltzoff demonstrated imitation in early infancy and proposed it as a powerful social learning mechanism by which infants begin to acquire the behaviors, skills, and norms of their culture. Through a set of classic studies, Meltzoff made key discoveries concerning the nature and functions of imitation in childhood.”

Meltzoff is the Job and Gertrud Tamaki Endowed Chair in psychology. Other recipients of the award this year are from Stanford University, University College London and the University of Michigan.

The award, the highest the association gives for contributions to the science of psychology, is named for American psychologist and philosopher (1842-1910).

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Washington Sea Grant’s Crab Team wins SeaDoc Society’s 2020 Salish Sea Award

The ‘s detection and study of the dangerously invasive European green crab has brought it the from the University of California, Davis-based .

The society, a program of the UC Davis, awards its Salish Sea Science Prize every two years to recognize scientists “whose work results in the improved health of fish and wildlife populations in the Salish Sea.” The award was announced on Earth Day, April 22.

The is an invasive species affecting ecosystems worldwide, damaging shellfish harvests and other native species and habitats. In the Pacific Northwest, it could harm Dungeness crab populations and eelgrass habitats.

Thanks to the WSG Crab Team, “major scientifically based efforts are being made to stop its spread before it starts,” the SeaDoc Society wrote. The Salish Sea Prize comes with a no-strings $2,000 cash award.

The WSG Crab Team, which is housed in the and supported through the Washington State Department of Fish & Wildlife, created a volunteer-based early detection and monitoring program for the European green crab that includes a map of “at-risk” sites, allowing prioritized monitoring of susceptible estuaries and lagoons. The team also provides technical expertise to government and tribal resource managers and information to the public.

Jeff Adams is project lead for the and Emily Grason is program manager. P. Sean MacDonald, a College of Environment faculty member, is co-principal investigator and Kate Litle is assistant director for programs at Washington Sea Grant.

Grason called the European green crab “probably the most notorious and damaging marine invasive on the planet.”

She added: “It’s unfortunately not just on our doorstep here in the Salish Sea, but it’s wandered into our foyer as well. Our goal is to keep it from overstaying its welcome.”

Read more on the SeaDoc Society . For more information, contact Grason at egrason@uw.edu

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National honors for College of Education researchers

Several faculty and students with the have received honors for 2020 from the .

, assistant professor, received Outstanding Dissertation awards in two categories and honorable mention in a third for her 2019 dissertation, “.” Listen to a with Washington.

Assistant professor , who studies teaching and learning writing in diverse classroom contexts, received an Early Career Award in the language and social processes category. Listen to a with Machado discussing her work.

Associate professor , a researcher with the , received an Outstanding Contribution to the Field Award in the category of education and sport. Hoffman wrote the recent book “.”

Other awards included an Out-of-School Time Emerging Scholar award for doctoral student ; and Miller and fellow doctoral student being accepted into the , co-sponsored by the association.

The association, called the AERA for short, canceled its April annual meeting, for the first time since World War II, due to the pandemic.

Read more about the honors and recipients on the college .

All prey animals, whether a swift-footed deer or a slow-moving snail, use cues from their environment to sense the presence of a threat. It’s what keeps them alive — or at least gives them a shot at getting away.

But the specific cues that trigger prey defenses vary depending on the species of prey and their history in the ecosystem, a new 91Ě˝»¨ study finds. The , published online Jan. 12 in the journal , analyzed the behavior of seven species of marine snails found in Washington waters — three native and four invasive — and discovered that native and invasive snails use different cues to assess risk.

The invasive snails were introduced unintentionally at least a century ago as hitchhikers on imported oysters. In experiments with these invasives, a 91Ě˝»¨researcher found that they fled quickly (as snails can do) and hid when they smelled chemicals released from crushed snails of the same species — meant to mimic a predator eating their close kin. This is surprising because these so-called “alarm cues” don’t provide the snails with much of a clue as to what or where the danger might be. Panicking with only vague information to go on could even be counter-productive, causing snails to miss their lunch unnecessarily, or actually make them more vulnerable to a predator.

By contrast, the three species of native snails didn’t react when they encountered the same situation. Instead, they went about their business until they had multiple sources of information, including from a predator and other prey, before fleeing or hiding.

In other words, the fear reactions in native snails were more finely tuned, while the invasive snails jumped ship at the first whiff of a threat.

“It’s pretty rare for a distinction between native and invasive species to be as consistent as it is here — which suggests it might hold true in other species and locations,” said author , an invasion ecologist at UW-based who recently completed her doctorate in biology at the UW.

This study is the first to compare multiple species and their reactions to threats using many different predator cues. Because the reactions of native and non-native snails split neatly, it suggests there could be a link between sensitivity to alarm cues and invasion success. On one hand, that can keep them from important tasks like eating and mating, but it also can fortify their strength as an invader, Grason explained.

“The non-native snails show up and they are just neurotic enough, and a bit wary, and that actually helps them survive in certain situations,” she said. “You end up with invasive snails that hide at the right time, even if they don’t know what the predator is. And that’s exactly what happens when snails show up in a new spot; they are surrounded by predators never encountered before. General wariness might keep them alive.”

Grason ran separate lab experiments for each species of snail. Two bins, with flowing seawater, were attached by a pipe, and she manipulated cues of a predation threat in the upstream bin while recording snails’ behavior in the downstream bin. The cues tested for all species included a crab, either hungry or fed, crushed snails of the same species and two other combinations of these factors.

The invasive snails’ catchall reaction to signals of danger can help ecologists better understand invasions and predict their impact on ecosystems, which is never easy.

“Ultimately, biological invasions are a Pandora’s box because we don’t know what will happen,” Grason said. “Nevertheless, understanding the details of an invasion — especially where there are and aren’t patterns — is important. Thinking about biological invasions in new ways is going to offer us more tools with which to understand and hopefully intervene, or mitigate the impacts on other species.”

This study was funded by the UW, the Conchologists of America, the National Shellfisheries Association, the Pacific Northwest Shell Club and the National Oceanic and Atmospheric Administration.

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For more information, contact Grason at egrason@uw.edu.

Grason dedicates this research to the memory of the late 91Ě˝»¨ecologist , who published his seminal work on “keystone species” in the same journal 50 years ago.