Summer & Fall 2024 ~ Newsletter

Updated: Sep 19

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Save the Date!

PCRG Winter Meeting | January 28, 2025 | Kingston, WA

Join us at the next annual PCRG Winter Meeting for an inside look at the 2024 larval crab monitoring season, results from PCRG’s genetics study, and other crab-tastic projects going on across the network. Stay tuned for registration details!

Larval Crab Monitoring

As the 2024 larval crab monitoring season comes to a close, PCRG partners across the region are pulling their light traps and working to compile data. Highlights include:

22 light trap sites in Washington (coordinated by Puget Sound Restoration Fund) and 28 sites in British Columbia (coordinated by Hakai Institute) participated in this year’s monitoring efforts.
Two new light trap sites were added to the network this year: one in Mukilteo (managed by the Washington Department of Fish and Wildlife), and one in the Wa’atch River near Makah Bay (managed by the Makah Tribe and funded by the North Pacific Coast Marine Resources Committee).
6 sites collaborated with the U.S. Geological Survey (USGS) by providing samples of their catch to detect and quantify the presence of European green crab larvae using genetic analysis.
A record-breaking 18 sites in WA deployed temperature loggers alongside their light traps, which increased the scope of temperature data collection across the network and can help us gain further insight into correlations between larval abundance and sea surface temperatures.

(Left) Dungeness crab megalopae. (Right) WDFW staff re-deploying their light trap in Mukilteo. Photos by Ally Galiotto.

In the Media

Puget Sound Restoration Fund (PSRF) posted an Instagram reel that provides a behind-the-scenes look at a typical day of light trap sampling at their site in Clam Bay, Manchester. The post garnered significant attention, with 90+ comments, 25k likes, and 320k views (and counting!).

WDFW published a blog post titled “Dungeness crab megalopae traps shine a light on future harvest opportunities”, which highlights their monitoring efforts at light trap sites in Mukilteo, Westport, and Tokeland. These three locations help fill critical gaps in the scope of our monitoring—Mukilteo in Whidbey Basin and Westport/Tokeland on the southern half of Washington’s outer coast.

(Left) WDFW staff counting light trap catch in Tokeland. (Right) Dungeness crab megalopae. Photos by WDFW.

Technical Team

PCRG’s Larval Crab Technical Team is gearing up to process this year’s data with two new experts on board! We’re thrilled to welcome our newest members:

Blair Winnacott (Washington Department of Fish and Wildlife)
Devynn Gately (Jamestown S'Klallam Tribe)

Student Spotlight

In recent years, our partners at Hakai Institute in British Columbia have utilized a new method to collect measurement data on Dungeness crab larvae captured in their light traps by using photos and image analysis software. While this method saves considerable time and effort in the field, a key question arose: how do image-based measurements compare to manual caliper measurements in terms of accuracy, precision, and feasibility?

Claire Curran, a Marine Biology student at the University of Washington (UW), explored this question through an independent research project over the summer. While assisting with light trap sampling at the UW-managed site in Shilshole Bay, Claire collected paired measurement data to directly compare image analysis results with caliper measurements. She presented her research at the recent PCSGA Annual Shellfish Conference and Tradeshow on September 11, but for those who missed it, she summarized her results here:

During the summer sampling series, I worked with Professor Sean McDonald to develop a new method for measuring the Dungeness crab megalopae using the image processing software, ImageJ. The current method of using a handheld caliper to measure total height, carapace height, and carapace width of each megalopae is time consuming, and measurements may be subject to bias due to the large number of people taking measurements throughout the season. This new method allows us to take a group photo of multiple megalopae and use ImageJ to measure dimensions of the individuals after field work has been completed. The overall result when comparing caliper measurements with ImageJ measurements was that caliper measurements tended to overestimate megalopae size for total height, carapace height, and carapace width. This is probably due to the difficulty of bringing the caliper close enough to the body of the megalopae, resulting in a larger size. ImageJ was specifically designed to measure small objects, while the caliper was not necessarily designed for these small animals, allowing us to assume that ImageJ is a more accurate measurement tool. Because of the efficiency of ImageJ, it is possible for fewer people to measure megalopae, which decreases biases that may occur when different people take measurements. The results of this research could be considered as a way to decrease effort in the field, increase accuracy of measurements, and reduce measurement bias between researchers. – Claire Curran, UW

(Left) Example photo used for image analysis. (Right) Claire taking pictures of Dungeness crab megalopae at the light trap site in Shilshole Bay. Photos by Ally Galiotto.

Intertidal Monitoring

This season, teams from Port Townsend Marine Science Center and WDFW successfully conducted juvenile crab surveys at Fort Townsend, Fort Worden, and Mukilteo using methods developed by the Swinomish Indian Tribal Community. As we look ahead, discussions are ongoing about how to best utilize this data, including possible funding mechanisms and future survey engagement. Stay tuned for updates as we explore expanding these efforts in the coming years!

Juvenile Dungeness crab found during an intertidal survey. Photo by Emily Buckner.

Community Engagement

Read on to learn how PCRG coordinators have showcased our work to local communities this summer. If you’ve been involved in any education or outreach endeavors, let us know, and we’d love to feature them in an upcoming newsletter!

Tune into the Nature Now podcast on Spotify to catch Emily’s interview on the local Port Townsend radio show, KPTZ, where she discussed Dungeness crab, PCRG’s ongoing projects, and the broader impact of our research on marine ecosystems.
Ally brought Dungeness crab research to K-5 students during a Beyond the Bell summer program in collaboration with Metro Parks Tacoma. Over three days, she shared information about crab ecology, fisheries management, and PCRG’s larval crab monitoring efforts before students got an up-close look at some live crab larvae!
From September 6-8, Emily and Ally hosted a light trap demonstration at the Port Townsend Wooden Boat Fest. Over the three mornings over 150 attendees learned about plankton, the PCRG larval crab network, and the importance of monitoring. A big thanks to local volunteers Silke, Jeff, Brad, and Lee for helping support this outreach undertaking!