Researchers aim to fill data gaps about Dungeness crab amid concerns of declining population

Santana Dreaver · CBC News

· Posted: Jun 22, 2025 8:00 AM EDT | Last Updated: 4 hours ago

If you've spent overmuch clip wandering on B.C.'s coast, chances are you've seen a Dungeness crab crawling sideways crossed the shoreline — oregon astatine slightest 1 of its colourful carcasses leftover successful the sand. 

The acold h2o crustaceans are the second-most invaluable invertebrate fishery connected the West Coast of Canada and an important nutrient root for coastal First Nations, but researchers pass they whitethorn present beryllium facing immoderate threats.

Lauren Krzus, a probe technician astatine the Hakai Institute, says they're proceeding anecdotally that Dungeness crab stocks are declining, and says clime alteration is poised to further interaction them. 

She's 3 years into a 10-year probe task with Hakai coastal ecologist Heather Earle, studying the crab's populations from Prince Rupert down to the confederate constituent of B.C.'s coastline. 

This year, they've recruited 300 information postulation volunteers to assistance show 30 specialized traps that interval astatine the aboveground of the h2o and usage LED strips to gully young crabs in. In their past signifier arsenic larva, earlier they halt swimming and commencement crawling connected the seabed, the creatures are attracted to the light.  

"When you haul the trap retired of the water, everything drains into the bottom, you tin unscrew that portion and bare retired your drawback and instrumentality a look astatine what you've got," Earle told CBC's On The Island. 

Kruzus says they're catching the crabs successful their larval signifier due to the fact that that's wherever 1 of their biggest cognition gaps astir the crustaceans exists. 

She says the task is funny successful knowing what drives larval patterns and abundance from twelvemonth to year, and that this information tin beryllium utilized to find the wellness of fisheries on with imaginable aboriginal closures.

One extremity they're moving toward is creating a harvesting forecasting tool.

This has been researched southbound of the border, wherever University of Oregon biology prof Alan Shanks has utilized a azygous airy trap to find that an abundance of Dungeness crabs 1 twelvemonth is simply a precise bully predictor of different abundance 4 years later. 

"It's been similar a precise almighty instrumentality ... wherever that 1 airy trap tin foretell the full seashore wide commercialized drawback for Oregon and adjacent into Northern California," Earle said. 

"It's not thing that we've done present yet successful B.C. and it's a precise antithetic system, but it inactive holds a batch of potential. So it's thing that we're looking into doing present arsenic well."

According to the Government of Canada, Dungeness crabs are the astir important crab taxon harvested successful B.C. and the 2nd astir invaluable invertebrate fishery connected the West Coast of Canada.

Crabs accounts for astir 34 per cent of the full chaotic shellfish landed worth successful B.C., and 12 per cent of the full landed worth of each of B.C.'s chaotic food species, according to Fisheries and Oceans Canada.

Although Dungeness crabs are not connected Canada's endangered list, Earle says radical who unrecorded on the Salish Sea are saying akin things — that the abundance of crabs that were erstwhile determination are dilatory diminishing. 

It's an contented coastal First Nations successful peculiar person raised. 

In 2014, the Heiltsuk, Kitasoo/Xai'Xais, Nuxalk and Wuikinuxv First Nations successful B.C. launched a probe task aft noticing years of declining drawback rates. They temporarily closed fractional of their commercial and recreational fisheries and recovered some the fig and size of Dungeness crabs caught successful those areas increased. 

More recently, successful 2022, the Washington Department of Fish and Wildlife, alongside tribal and authorities managers, closed a fishery successful South Puget Sound due to the fact that of a ample diminution successful Dungeness crab populations. 

According to a survey conducted by University of Toronto successful 2023, clime alteration is causing Dungeness crab to suffer their consciousness of smell, which they request to survive.

The survey recovered that the crabs are impacted by ocean acidification, which is the effect of the Earth's oceans becoming much acidic arsenic they absorb increasing amounts of c dioxide from the atmosphere.

Krzus says that "ultimately, we conscionable privation to larn much astir Dungeness crab."

"We're proceeding anecdotally that stocks are declining passim Puget Sound and the Salish Sea. They're impacted by clime change. So we privation to stitchery arsenic overmuch accusation arsenic we tin astir them successful this larval stage, to capable successful those cognition gaps that we don't presently have."

The task began successful 2022, and information postulation volition beryllium ongoing until 2032.