For more than a decade, scientists have been puzzling over what was causing billions of starfish to dissolve into piles of white goo. Sea star wasting disease has ravaged starfish populations, wiping out 90% of the once common sunflower sea star. Now, researchers have finally identified the culprit. Madeleine Finlay speaks to Dr Melanie Prentice, one of the team to crack the case. She explains the impact the disease has had on the marine environment, how they found the pathogen responsible, and what it means for sea stars’ recovery