Treaty tribes and their partners in the Pacific Northwest Crab Research Group (PCRG) want more than data out of their research—they want to see how a collaborative approach to collecting data can help co-manage fisheries.
A paper published recently by the American Fisheries Society explores how PCRG’s collaboration methods, including multiple partners collecting data and strengthening those relationships, can support managing the Dungeness crab population that has been increasingly relied upon by harvesters since finfish populations have declined.
The PCRG includes tribal, state and federal governments, nongovernmental organizations, academic institutions and local communities. It works to produce standardized biological data sets on Dungeness crab throughout the region, said Emily Buckner, lead author of the study and one of the program coordinators.
While harvests have been closely monitored and population surveys conducted for decades, fisheries co-managers still don’t have a complete picture of the crab life history, such as larval movement patterns, genetic population structure, and environmental influences on a crab’s life stages, Buckner said.
Dungeness crab are important to the tribes specifically as a traditional food as well as an economic source for tribal fishers. However, the population is challenging to manage because of data gaps throughout the Salish Sea. Information collected from the samples of tiny crab larvae, known as megalopae, could help co-managers better understand stressors to the population, such as overfishing and the changing climate and ocean conditions.
“This collaborative effort demonstrated that the PCRG’s structure is effective for developing robust research projects that address data gaps for this population,” Buckner said.
The primary data collection method has been using light traps—a five-gallon bucket-sized floating collection device that uses light to attract and trap crab larvae, typically located off piers and docks, set out 1-2 days at a time April through September.
Participants started setting out light traps in 2019, from as far north as Heriot Bay on Vancouver Island, B.C., to Zittle’s Marina in Olympia. In 2023, 42 light traps were set, collecting data and contributing to the database.
“From PCRG’s inception in 2018, we have seen the value in collaboration to collect data across the Salish Sea on this important species,” said Neil Harrington, environmental biologist for the Jamestown S’Klallam Tribe and a member of the coordinating committee of PCRG. “No one entity could collect this powerful of a data set that is giving us a better understanding of the distribution and timing of early life stages of Dungeness crab.”
From the data collected, it has been observed that the abundance of larval crab caught within the light trap network has varied by location and year. The highest annual abundance was found consistently in the Central Salish Sea (North Puget Sound, San Juan Islands, Whidbey Island and Northeast Olympic Peninsula) and northern Hood Canal, with the lowest abundance in the southern Salish Sea and southern Hood Canal.
Larger larvae showed up in April and May (about 1/3 inch like a small jewelry bead), with progressively smaller megalopae arriving in subsequent months (about a 1/4-inch size).
The Jamestown S’Klallam Tribe is slated to conduct additional research through the PCRG adult crab workgroup, Harrington said, to develop a unified survey that will provide baseline population data, independent from the commercial fishery, and can be linked to the larval crab data. It is hoped that this will give Dungeness crab managers improved capacity to predict future catch and better safeguard the fishery.
Above: Emily Buckner, PCRG program coordinator and Neil Harrington, Jamestown S’Klallam Tribe environmental biologist, sort through contents of a light trap stationed in Sequim Bay. Story and photos: Tiffany Royal
