Threatened Sea Stars Are Finding Refuge in BC Fjords

Scientists at the Hakai Institute are finding hope in the fjords of British Columbia’s Central Coast. New research shows that endangered sunflower sea stars (Pycnopodia helianthoides) are surviving disease outbreaks in these cold-water ecosystems—but not due to temperature alone.

The sunflower sea star—which can grow 20 arms and measure a meter across—was once a common fixture of the Pacific Northwest intertidal zone. Despite its large size, Pycnopodia is a fast and voracious predator of bottom-dwelling species, such as sea urchins, making it important for the health of kelp forests. But in 2013, a marine malady known as sea star wasting disease (SSWD) took hold, wiping out more than 90 percent of all sunflower sea stars between Alaska and Mexico in a handful of years.

Disease outbreaks have been linked to marine heatwaves—which are becoming more frequent with climate change—suggesting that waters with consistently cold temperatures could act as marine refuges for Pycnopodia. The new study, conducted in partnership with the Central Coast Indigenous Resource Alliance (CCIRA) and Fisheries and Oceans Canada (DFO), finds that Central Coast fjords may hold keys to sea star survival.

It was collaborators from CCIRA and member First Nations who first reported sightings of large Pycnopodia in the Central Coast fjords—a sign of remnant populations that had dodged SSWD.

“We got to see what the subtidal zone used to look like before the wasting disease outbreak,” says Alyssa Gehman, the lead researcher on the study, who visited Burke Channel for a dive after getting the tip from CCIRA. “It was like looking into the past. It was magical.”