Abstract
Lifespans of animals inform us about generation length, underpinning assessments of extinction risk and models for fishery harvest strategies. Uncertainty and contention endure about the lifespans of coral reef echinoderms, especially soft-bodied sea cucumbers. We used a photographic mark–recapture study at Lizard Island, Australia, to validate longevity, growth and displacement in the large sea cucumber Bohadschia argus . This species is harvested in fisheries throughout the western central Pacific and Southeast Asia. Using the photographic mark–recapture method, four individuals, estimated to be up to 22 years old in 2012, were recaptured 11 years later. Most eye-spots on the matched individuals persisted over the study period. The recaptures confirmed a lifespan of at least 33 years and an estimated generation length of at least 21 years. Long-term growth of the individuals was modest, with body size increasing by just 0.2–1.3% per year. Some individuals had displaced little over the period. Our data prove multi-decadal longevity in coral reef sea cucumbers, underscoring their vulnerability to extinction and a need to apply conservative estimates of generation length to conservation planning and fishery models.