A purse seine vessel with a whale shark caught as bycatch in the Pacific. Whale sharks, being slow swimming filter feeding fish, act as natural aggregation devices for tuna in tropical oceans and are killed in unsustainable numbers in purse seine fisheries. The vessels either set their nets on these creatures to catch the surrounding tuna or the whale sharks are caught in nets around fish aggregation devices (FADs) that attract these magnificent creatures as well as other sharks, turtles and juvenile tuna as well as the targeted adult tuna species.