Rapid Assessment of Sea Turtle and Marine Mammal Bycatch in the Union of the Comoros

Abstract

The Union of the Comoros is host to internationally-significant populations of sea turtles, dugongs and cetaceans, all of which are potentially threatened by incidental catch in artisanal fishing gears. This work presented here was part of a larger initiative, known as Project GloBAL (Global Bycatch Assessment of Long-lived species), to evaluate artisanal fishing effort and bycatch of sea turtles and marine mammals in data-deficient areas. Questionnaire surveys were conducted with 409 out of the estimated 8,500 artisanal fishers in the Comoros, on the islands of Grande Comore (25/44 landing sites) and Moheli (5/13 landing sites). Sea turtles (mainly Chelonia mydas) were reportedly captured in large numbers, although it was not always clear if captures were accidental or deliberate. Lower rates of turtle capture were reported from Moheli, possibly as a result of awareness-raising activities associated with Moheli Marine Park. Gillnets presented the most serious bycatch-related threat to dugongs (Dugong dugons) and current mitigation efforts such as closed areas to limit gillnet use are essential for the continued presence of this species in the Comoros. Cetaceans were rarely captured and mortality was reportedly low; with spinner dolphin (Stenella longirostris) the most common of several species recorded as bycatch.