In pursuit of information about the movement of adult Dungeness crab, the Swinomish Indian Tribal Community recently launched a pilot project that dispatched research tags on about 500 of the critters.
Across two days in April, staff of the tribe’s shellfish program trapped crab for the study, noting the size, sex, shell hardness and location of capture for each crab tagged. The tagging took place in Similk Bay, a body of water adjacent to the Swinomish Reservation and north of the larger Skagit Bay.
Each of the blue tags have individual tag numbers and a phone number for the Swinomish research team. The tribe is asking tribal and nontribal fishers to contribute to the pilot project by reporting—by call or text message—the capture of tagged crab, its tag number and catch location.
Many of the tagged crab are of legal size for harvest, which can be kept after the tag information is shared. Others are undersized for harvest but valuable to the study, meaning the tag information should be shared before the crab is released.
Anyone who reports capture of a tagged crab for the study will be entered into a drawing for a new crab pot.
“What we’re most interested in is simply can we recapture crab? If we can recapture them, the other question is where have they moved to?” said Julie Barber, senior shellfish biologist for the Swinomish Tribe. “This is potentially how we can start answering questions about movement, and, with a larger study in the future, perhaps estimate abundance.”
If the pilot project is successful in gathering relevant data, research partnerships could extend the study throughout the Salish Sea, and results could eventually inform management of the species.
“The tribe is very interested in ensuring the long-term sustainability of the Dungeness crab fishery,” said Tandy Wilbur, a Swinomish senator and the tribe’s fisheries manager. “We are excited about the prospects of having a larger study and network so we can apply what we learn to our management practices.”
State and tribal comanagers set catch windows and limits for seven commercial harvest management regions within the Salish Sea each year. Similk Bay is part of the management area that includes Skagit Bay, Saratoga Passage, Penn Cove, Port Susan Bay and Possession Sound—all waters near Fidalgo, Whidbey and Camano islands.
The issue is that crab don’t live statically within mapped boundaries, and how far, how quickly and how often they may travel within or between management areas is unknown.
“We currently manage the crab by these very distinct boundary areas, or management regions,” said Maddison Hicks, shellfish management biologist for the Swinomish Tribe. “Each management region has its own set quota, and if the crab are moving around between these management areas, that’s very important to think about.”
The first recapture in the pilot project was one legal-size male crab caught during a tribal test fishery in May. While still within the local management area, the crab moved from Similk Bay into Skagit Bay—a first clue that Dungeness in these waters are indeed mobile.
“It’s exciting to see this starting,” said Barber, who brings extensive experience tagging crab during studies in Alaska. “There are definitely a lot of unknowns for Salish Sea crab, and this could potentially be a method to answer some of those questions.”
The tags dispatched this spring could yield data across several years. Attached to the hind muscle of each crab through its shell, the tags should withstand at least one molt.
“They can grow, molt and retain that tag,” Barber said.
Caught a crab with a blue tag? Call or text 360-391-3652 with the tag number and location of capture. Individuals who report crab recaptures are entered into a drawing for a new commercial or recreational crab pot.
Above: Blue tags are affixed to hundreds of Dungeness crab in the greater Skagit Bay area for a study of crab movement in the region. Researchers are asking crabbers to report recapture of tagged crabs, including the specific tag number found and location caught. Photos from the Swinomish shellfish team. Story by Kimberly Cauvel.
