March 24, 2025 — Researchers are waging a quiet battle in the Pacific Northwest to protect one of the region’s most iconic species — the Dungeness crab.
Using light traps, scientists at the MaST Center Aquarium in Des Moines are gathering data that could help safeguard the future of Washington’s most valuable wild-caught fishery.
The study aims to fill in gaps in the biological data on Dungeness crabs. Researchers hope by monitoring the early stages of their development, they can better predict crab populations and avert crises like the one that closed the fishery in South Puget Sound a few years ago.
According to the Washington Department of Fish and Wildlife, tribal and recreational crabbing plummeted in South Puget Sound in the last 15 years, dropping from 214,404 pounds harvested in 2012 to only 8,679 pounds in 2017.
“That was a big wake-up call for fisheries, co-managers, and part of the reason the Pacific Northwest Crab Research Group (PCRG) formed,” said Ally Galiotto, Puget Sound Restoration Fund. “We still don’t know exactly what happened. It’s a sobering reality that sudden drops in population could happen elsewhere, and we won’t necessarily know why or when they will happen.”
To capture crab larvae, a light trap is deployed from docks in Washington and British Columbia. Each trap consists of a transparent bucket with an LED light strip that activates at night. The light mimics moonlight, drawing in the larvae, while a funnel prevents larger creatures from entering the trap. Once the larvae are captured, the samples are sifted, counted, and analyzed before being returned to the water.