The PCRG convened at Kingston Village Green Community Center on Thursday, January 25, 2024 for our annual all-member meeting, funded by the NOAA Saltonstall-Kennedy Program and Puget Sound Partnership. With over 90 in-person and virtual attendees, the day-long event featured lightning-style presentations on current and pending research, followed by an engaging panel discussion with experts Dr. Alan Shanks and Dr. Leif Rasmuson, whose research on larval Dungeness crab dynamics along the Oregon coast inspired the development of PCRG’s own larval crab monitoring network in the Salish Sea!
PCRG members at the 2024 Annual Meeting. Photo by Emily Buckner.
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Group Updates
PCRG Charter
As part of a biennial review process, the PCRG Charter (available here) was recently updated and adopted in January 2024 by the group’s Coordinating Committee. After soliciting member feedback, the Coordinating Committee decided to update the group’s mission statement to reflect a broader interest in researching various crab species in the Pacific Northwest, and added an accompanying statement of the group’s current strong focus on Dungeness crab. An addendum to the Charter was also introduced that offers guidance on co-authorship when writing PCRG manuscripts.
If you are interested in joining our collaboration as a data collector, educator, or researcher, we invite you to sign the updated Charter to become an official ‘general member’ of the group. Contact the program coordinators at pnwcrab@gmail.com to learn more!
Coordinating Committee Election Results
Elected members of the 2024-25 PCRG Coordinating Committee are listed below. Farewell and thank you to Neil Harrington (Jamestown S’Klallam Tribe), who served on the Coordinating Committee for the past 3 years, and Mary Fisher (UW), who served as the Committee’s first ever student representative in 2023-24. Warm welcome to the Committee’s newest members, Courtney Hart and Amy Pumputis!
Julie Barber, Swinomish Indian Tribal Community (Tribal Rep. #1)
Courtney Hart, Port Gamble S’Klallam Tribe (Tribal Rep. #2)
Gianna Pantaleo, Suquamish Tribe (Tribal Rep. #3)
Daniel Sund, WDFW (State Rep.)
Brian Allison, Puget Sound Crabbers Association (Federal/Academic/NGO/Industry/Other Rep. #1)
Sean McDonald, University of Washington (Federal/Academic/NGO/Industry/Other Rep. #2)
Rich Childers, WDFW retired (Open Rep.)
Amy Pumputis, Oregon State University, WDFW (Student Rep.)
Current Work in the PCRG Community
Larval Crab Monitoring
To kick off the morning, technical team members Heather Earle (Hakai Institute) and Allison Brownlee (DNR) presented observations from PCRG’s light trap network in 2023 – the group’s fifth consecutive year of larval crab monitoring. Highlights included:
43 light trap sites: 18 in WA (coordinated through PSRF) and 25 in BC (coordinated through Hakai Institute)
47 data collection partners: 20 in WA and 27 in BC
38,796 total hours fished
2,548 ‘good’ catch data records
3,100 measurements
426,955 Dungeness crab larvae recorded
Largest overall catch: 30,827 at Horseshoe Bay (HOR) on June 14 after two nights of fishing
Largest catch in a single night: 18,653 at Semiahmoo (SMS) on July 4
First detection: April 17 at Westport (WTP)
Last detection: September 26 at Semiahmoo (SMS) – a new record!
Washington’s outer coast observed peak abundance in May, while most inland sites observed their peaks in July (similar to 2022).
Sites in the north-central area of the Salish Sea (HOR, HEA, SMS, and ANA) observed the highest overall abundances, with decreasing numbers seen to the north and south.
Consistent with previous years of monitoring, measurement trends revealed a decrease in size over the season, though 2023 had a comparatively smaller wave of early-arriving megalopae.
Light trap monitoring sites in 2023. Red markers show sites coordinated through Puget Sound Restoration Fund; blue markers show sites coordinated through Hakai Institute.
PCRG Member Updates
Jay Dimond (WWU) shared an update on the Dungeness crab population genetics study, which involved sampling 1,457 unique adult and larval crabs across Washington’s Salish Sea between 2021 and 2022. The genomes of each individual will be analyzed using Low Coverage Full Genome sequencing, and results are coming soon. Thank you to all the PCRG partners who collected samples for this effort!
In December, Northwest Treaty Tribes published an article highlighting this work.
Jessica Linkemyer and Francesca Marvin (UW Tacoma) introduced their DNA barcoding project, which aims to identify the species of different crab zoea and megalopae captured in light traps at Point Defiance (PDM) and MaST Aquarium (MST). Out of 41 larval crab samples, 12 unique species were identified through genetic barcoding. An identification guide catered towards volunteers is currently in development. This collaborative work was done in partnership with Point Defiance Zoo and Aquarium, Highline College, Seattle University, Bellarmine College Preparatory, and the Tacoma Science and Math Institute.
Results from a Dungeness crab movement study, presented by Katelyn Bosley (WDFW), offered insights into adult crab movement patterns across three Puget Sound management areas (Dungeness Spit, Port Townsend Bay, and Hood Canal). Between 2002 and 2007, WDFW worked alongside the Jamestown S’Klallam, Skokomish, and Suquamish Tribes to tag over 7000 adult crabs using floy tags. Over 560 tagged crabs were ultimately recovered, yielding an 8% recovery rate. Interestingly, crabs appeared to stay within their respective management regions. Assuming a direct path from release to recovery locations, 88% of recovered crabs moved less than 100 meters per day, while the maximum rate of travel was over 800 meters per day. The longest distances were traveled by crabs tagged in Hood Canal, with many of them moving north towards the canal entrance. Going forward, WDFW hopes to implement a tagging study in other crab management areas, and ultimately build a movement probability matrix for Puget Sound.
Dungeness crab with a floy tag placed along the epimeral suture line, which helps ensure the tag is retained through molts. Photo by WDFW.
Carter Johnson (University of Alaska Fairbanks) overviewed his PhD research investigating how sea otters and Dungeness crab coexist in Southeast Alaska, considering that commercial crab landings have remained relatively consistent despite a steady increase in the local otter population. His work explores the possibility of crabs utilizing a depth refuge, as well as potential spatial shifts in the Dungeness crab fishery. He is currently testing the hypothesis of ‘bottom-up’ population control by deploying light traps to track larval crab abundance in the region. At a pilot site in Juneau in 2023, Dungeness crab megalopae were detected through mid-October – much later than we observe here in the Salish Sea!
Cody Szuwalski (NOAA AFSC) provided background on the collapse of Bering Sea snow crab populations that led to a fishery closure in 2022. He described the modeling process that related estimated mortality to environmental stressors, which consistently identified temperature and size of the mature population as significant covariates. Ultimately, increased metabolic demands, changes in weight-at-size, and decreased spatial extent all suggest that starvation may have played a role in the fishery’s collapse.
Szuwalski et al. (2023) describe this research in “The collapse of eastern Bering Sea snow crab”,
accessible here.
Micah Horwith (Ecology) discussed how larval crab could potentially serve as an indicator of ocean acidification (OA) conditions. Washington waters are approaching biological risk zones, and as OA conditions worsen, crab larvae sustain visible damage to their carapaces. Due to their vertical diel migration patterns, crab larvae are also susceptible to diverging OA conditions between deep and shallow waters, and carapace dissolution increases as the gradient widens.
European Green Crab
A new study led by Carl Ostberg (USGS) seeks to explore the efficacy of light traps in capturing European green crab (EGC) larvae. The project aims to use genetic markers to detect and quantify EGC larvae captured in a subset of PCRG light traps, located in areas with high, moderate, and low levels of adult EGC abundance. USGS also plans to test whether EGC larvae are attracted to light by deploying a second un-lit trap at select sites.
Last year, Washington Sea Grant and WSU Extension teamed up to launch a volunteer-based early detection program for EGC across inland Washington shorelines, called Molt Search. The program aims to teach volunteers simple, standardized steps for searching and reporting on the presence and absence of EGC molts on their local beaches. Out of nearly 350 reports submitted last year, over 50% contained optional information on Dungeness crab molts, which suggests this datastream could potentially be of value to the PCRG network!
Learn more about the program and get involved: wsg.washington.edu/moltsearch.
All Molt Search data is available for download through MyCoast: https://mycoast.org/wa/crab
Dungeness and red rock crab molts found during a timed survey in Oak Harbor on November 23, 2023. Photo by Susan Mador (view the full Molt Search report here).
Pending and Future Work
A new proposal was submitted to the NOAA Saltonstall-Kennedy Program, entitled “Building capacity for resilience in the Dungeness crab fishery: Developing a stock assessment to improve science-based decision making in the southern Salish Sea”. Led by Emily Buckner (PSRF), Katelyn Bosley (WDFW), Austin Paul (Point No Point Treaty Council), Matt Nelson (Swinomish Indian Tribal Community), and Oliver Miler (NWIFC), the proposed project aims to implement the first fishery independent survey of Dungeness crab in Puget Sound. The objectives include developing a stock assessment framework, creating a data access and sharing plan for co-managers, and ultimately strengthening relationships between crabbers and fishery managers. If funded, this effort would begin in September 2024.
Kathryn Meyer (WDFW) shared information about a trawl survey data analysis project focused on developing single-species indices of abundance for groundfish and benthic invertebrates in Puget Sound. These trawl surveys were established in 1987 to monitor local flatfish populations, though data is collected on a wide range of species, including Dungeness crab. The project aims to address estimation bias, survey design differences, and spatial variability concerns over time, utilizing a spatiotemporal modeling approach.
Emily Bishop (UW) presented her proposed PhD research on an intertidal survey and habitat suitability model for Dungeness crab in South Puget Sound. This work aims to assess suitable habitat features for juvenile Dungeness crab, identify areas with the most and least suitable intertidal habitat, and explore pathways to enhance instar survivorship.
To contribute to this effort, PCRG members are invited to participate in an intertidal survey in August 2024, following existing protocols developed by the Swinomish Indian Tribal Community (SITC). If you’re interested, please fill out this short survey!
Surveying juvenile Dungeness crab during an intertidal survey. Photo by SITC.
Research Spotlight: Larval Dungeness Crab Dynamics & Applications
Oregon Coast Long-term Monitoring Efforts
Dr. Alan Shanks (OSU) and Dr. Leif Rasmuson (ODFW) traveled up the coast to share insights and lessons learned from their long-term larval crab monitoring efforts in Coos Bay, Oregon. After experimenting with multiple light trap locations around Coos Bay, they ultimately focused their data collection efforts on a single site, monitored over 23 years with the help of around 150 undergraduate interns. Larval crab abundance data from this light trap has been used to predict statewide commercial fishery landings in Oregon with relatively high levels of accuracy.
Annual catch of Dungeness crab megalopae in Coos Bay has varied significantly, ranging from 2,000 to 2.7 million larvae per year. By contrast, annual crab landings in Oregon have only varied by a factor of 5. The lowest larval catches were observed during strong El Nino events, while higher catch rates typically occurred (1) when the Pacific Decadal Oscillation (PDO) was in a negative phase, (2) when the date of the spring transition was earlier, or (3) when the amount of upwelling was greater. El Nino events and the PDO both alter the relative north-south transport of larvae along the West Coast, while springtime upwelling relates to the onshore transport of megalopae.
When annual light trap catch is plotted against commercial landings, it appears that years of low megalopal abundance correlate to the highest per capita recruitment, while years of high megalopal abundance correlate to lower per capita recruitment. In other words, as the abundance of megalopae increases, future commercial landings decrease. While the number of megalopae caught in Coos Bay can predict commercial landings in both Oregon and California, the same does not hold true for Washington, likely due to fundamental differences in population dynamics and circulation patterns.
Want to learn more? Explore the evolution of the work that inspired the formation of PCRG's own light trap network:
Shanks and Roegner (2007) identified a relationship between megalopae abundance and the date of the spring transition. See “Recruitment limitation in Dungeness crab populations is driven by variation in atmospheric forcing” (link).
Shanks et al. (2010) found that the number of returning megalopae also varies with the PDO. See “Using megalopae abundance to predict future commercial catches of Dungeness crabs (Cancer magister) in Oregon” (link).
Shanks (2013) introduced a regression with the amount of upwelling during the larval return period. See “Atmospheric forcing drives recruitment variation in the Dungeness crab (Cancer magister), revisited” (link).
A new report (coming soon!) will explore the effect of marine heatwaves on recruitment, assess variations in recruitment success with larval returns, and investigate why the relationship between larval returns and commercial catch appears as two distinct curves.
Oceanographic Context
Liz Tobin (Jamestown S'Klallam Tribe) provided a comprehensive oceanography ‘primer’ to contextualize the physical environments where PCRG’s light trap work takes place, first explaining the dominant circulation patterns along the coast. As a glacially-carved, fjord-type estuary, Puget Sound exhibits complex internal circulation patterns that are highly influenced by its bathymetry – three major sills in Admiralty Inlet, Hood Canal, and the Tacoma Narrows restrict water flow, contributing to basin-specific water conditions and residence times. Episodic patterns of coastal upwelling further impact plankton abundance and distribution.
After five years of larval crab monitoring, the biggest question our network hopes to answer is: can megalopal abundance be used to predict adult crab landings in the Salish Sea? However, we first need to consider:
What is the source of Dungeness crab larvae in Puget Sound?
How does estuarine circulation influence larval transport and retention?
Do we need to utilize a more sophisticated bio/physical modeling approach at the basin level?
PCRG Larval Crab Monitoring Efforts to Date
Members of the larval crab technical team – Sarah Grossman (SITC), Claire Cook (SITC), and Margaret Homerding (Nisqually Tribe) – provided a holistic overview of trends observed during PCRG’s first five years of light trap monitoring.
Sampling a light trap (left). Several species of crab megalopae commonly captured in PCRG light traps (right).
Photos by SITC.
During the first three years of monitoring (2019-2021), most sites recorded peak megalopae abundance in June, while in 2022 and 2023 peaks occurred one month later, potentially due to cooler than average spring and summer water temperatures. A new site on the outer coast, however, observed peak abundance in May 2023 with its last detection in July, highlighting unique larval delivery patterns between coastal and inland waters. In 2019, an El Nino year, the network observed its lowest numbers of Dungeness crab larvae thus far, and sites near the Strait of Juan de Fuca recorded a comparatively strong pulse of early-arriving megalopae. In general, sites in the central region of the Salish Sea observe the highest volumes of megalopae, with decreasing abundance to the north and south. Distinct temporal pulses in larval delivery, as well as size differences between early and late-arriving megalopae, suggest that larvae may be sourced from more than one population.
With results from ongoing genetics work and an improved understanding of circulation patterns within and between basins, we can better determine the extent to which these peaks represent coastal versus locally-retained larvae. While the network still has a long way to go before the development of a forecast model, we finally have our first data point linking annual larval catch in 2019 with commercial harvest in 2023. In the meantime, we can continue to fill data gaps surrounding the early life history stages of Dungeness crab, from examining the physical and biological mechanisms that drive larval delivery to the basin-specific behavioral adaptations that larvae exhibit.
Panel Discussion
Our afternoon presenters took to the stage to field questions from the audience and discuss considerations as PCRG looks towards the development of a predictive model. Following the panel, PCRG members were invited to reflect on the following questions:
What steps needed to be taken to develop a harvest forecast model in the Salish Sea or along Washington’s outer coast?
What is the current and potential value of the PCRG larval crab monitoring network? What other research questions, beyond predictions, can (and should) we be focusing on?
Panelists (left to right): Leif Rasmuson (ODFW), Alan Shanks (OSU), Liz Tobin (Jamestown S’Klallam Tribe), Sarah Grossman (SITC), Claire Cook (SITC), and Margaret Homerding (Nisqually Tribe). Moderated by Emily Buckner (PSRF). Photo by Julie Barber.
Internal waves are likely a major driver of larval transport, and megalopae have been observed "surfing" along surface currents in Oregon
In modeling efforts, we must consider the source of Dungeness crab larvae in Puget Sound, settling behaviors, and impacts of oceanographic conditions on larval dynamics
It’s crucial to monitor both high and low-catch light trap sites to explore potentially locally isolated populations (i.e., leave no site behind!)
Since we are only tracking relative larval abundance, light traps used across the network should be similar, but don’t need to be “perfectly” standardized
Monitoring instars in the intertidal and subtidal can provide insights into growth trajectories
General tips for success, courtesy of Dr. Shanks: have patience, explore related projects during waiting periods, and recruit help at your site!
In the News
Ilwaco community rallies to salvage crabbing season after fire
Seattle Times | Isabella Breda | January 29, 2024 | Link
Dungeness crab: The West Coast’s forever fishery
Capital Press | Kyle Odegard | February 1, 2024 | Link
Jamestown S’Klallam Tribe, partners using Dungeness crab DNA for population study
Northwest Treaty Tribes | Tiffany Royal | December 1, 2023 | Link
Cases of mistaken crab identity underscore request to report and release suspected European green crabs
WDFW Blog | February 13, 2024 | Link
Sea Change: How and When Washington’s Catch Ebbs and Flows
Seattle Met | Allison Williams | February 13, 2024 | Link
Washington’s coastal Dungeness crab commercial season opens Feb. 1
Matthew George & Bridget Mire, WDFW | January 24, 2024 | Link
2023-24 Washington Coastal Dungeness Crab Fishery Newsletter
WDFW | 2nd Edition | Link
Behold: the Dungeness Crab Doughnut from Seattle's Boat Bar!
K5 News | Kim Holcomb | January 17, 2024 | Link
Save the Date!
PCRG Hands-on Light Trap Repair and Construction Workshop
March 19, 2024 | Port Townsend | Contact pnwcrab@gmail.com for details
