Having found a mysterious killer of sea stars, B.C. scientists see a way to stop it

IN DEPTH Project Sail Mary Having found a mysterious killer of sea stars, scientists see an ingenious way to stop it REPORTING AND PHOTOGRAPHY BY JESSE WINTER MAINE ISLAND, B.C. THE GLOBE AND MAIL PUBLISHED 49 MINUTES AGO COMMENTS SHARE SAVE FOR LATER A mysterious disease is destroying stars and threatening critical ecosystems. Scientists are stumped, but they toil away in laboratories and distant, inhospitable environments, searching for an answer. It’s not the plot of an interstellar sci-fi movie: It’s the groundbreaking science being done by a co-operative of marine biologists trying to save western North America’s sea stars. In 2025, Canadian researchers identified the culprit: star-killing bacteria called vibrio pectenicida. But the discovery only prompted more questions: Where did they come from? Why had the outbreak exploded so suddenly? Can anything be done to stop it? The outbreak of what came to be known as sea star wasting disease began spreading up and down the Pacific coast, from Mexico to Alaska, in 2013. It devastated sea star populations, including wiping out almost 90 per cent of sunflower stars, the largest sea stars in the world. “We lost over six billion of them,” said Alyssa Gehman, an adjunct professor at the University of British Columbia and a marine disease ecologist at the B.C.-based Hakai Institute. Open this photo in gallery: This sunflower sea star was liquefied to death in 2015 off B.C.'s Calvert Island. Identifying the disease that caused this would take another decade; in the meantime, billions of animals died. COURTESY OF GRANT CALLEGARI/HAKAI INSTITUTE Open this photo in gallery: Healthy sunflower sea stars come in a mix of colours, with up to 24 arms for each adult. JOE GAYDOS, SEADOC SOCIETY VIA THE CANADIAN PRESS It was Dr. Gehman’s team that made the breakthrough in August, 2025, identifying vibrio pectenicida as the cause of the outbreak. The bacteria essentially attack sea stars from the inside out, slowly liquefying their guts until they collapse into piles of goo. While they are capable of sickening and killing all types of stars, the giant sunflower sea stars, which have dozens of limbs and can grow to the size of a bicycle wheel, were hardest hit. It’s a slow, hideous death that has critical effects on both sea star populations and the ecosystems where they live. Sea stars are important predators in their communities that help to keep their prey populations in check – so important, in fact, that…