The Jamestown S’Klallam Tribe is gathering new information about Dungeness crab that will help manage the population.
“Our goal is specifically to re-evaluate the peak molting period of Dungeness crab in management region in eastern Strait of Juan de Fuca,” said Devynn Gately, the tribe’s crustacean biologist. The management region includes Sequim Bay, Discovery Bay and near Port Angeles.
Understanding the timing of the molting period is vital for protecting the resource, Gately said.
During molting, crab shed their hard shell, becoming extremely soft and vulnerable to predators and handling mortality. In addition, female Dungeness crab mate right after molting, so closing the fishery during peak molting ensures a sustainable population.
“We’re trying to avoid harvesting during this time frame to protect the resource and benefit our fishers,” Gately said.
The tribal fishery typically is closed April 1-June 21, but tribal fishers have advised scientists that soft-shelled crab are still being found after the closure period, during the harvest season.
“So what does this mean?” Gately said. “Is it a change in the season of the molting period due to shifts in environmental conditions? Is it location based, dependent on habitat? Is it time to reconsider the timing of the harvest window and closure period?”
Prior to the study, Gately held a workshop with Jamestown’s crab fishers to get an idea of where to sample and other logistics they come across when harvesting.
“Getting that input from the fishermen helped tremendously,” she said.
Since last November, the tribe has been sampling crab once a month by placing 36 pots throughout 12 sites. They note each crab’s sex, carapace width and shell condition before returning it to the water.
Sensors attached to a crab pot at each site record water temperature and dissolved oxygen data, tracking whether those environmental factors could be associated with shell condition.
This work is supported through Washington Sea Grant’s Pacific Northwest Crab Research Group, a collective of tribal and state co-managers and other researchers.
“The idea is to streamline everything,” Gately said. “If we’re all doing crab survey work and collecting similar data, then we can share the data and have it be applicable across crab management regions.”
A Dungeness crab being documented by size and sex for a study about peak molting periods in Puget Sound. Story and photos by Tiffany Royal
