Hagfish have been commercially fished in Asia since the 1940s. This new study shows that after local stock depletion hagfish fisheries expanded around the world with some serial depletion patterns as in sea urchin and sea cucumber fisheries. In Atlantic Canada, hagfish landings and fishing effort increased 24-fold over the past 20 years with strong spatial expansion. The sustainability of current hagfish fisheries is questioned given the limited knowledge, assessments and regulations.