Tuna Fishing Welfare and Bycatch

Industrial tuna fishing causes welfare harms through bycatch of non-target species, capture stress in tuna themselves, and the onboard handling practices that determine the welfare of caught fish.

Key Facts

Purse seine nets used in tuna fishing can encircle schools containing thousands of fish
Fish aggregating devices draw in enormous quantities of juvenile tuna and bycatch species including turtles and sharks
Longline tuna fishing causes bycatch of seabirds, sea turtles, and billfish at significant rates
Pole-and-line fishing has significantly lower bycatch rates but requires more labour and vessel time
Tuna experience capture stress measurable in cortisol and physiological changes during and after netting

Welfare Considerations

Tuna fishing welfare operates at two levels: the welfare of target tuna, and the welfare of the enormous bycatch associated with industrial methods. For bycatch species including sea turtles, sharks, and seabirds, the welfare harms are acute and frequently fatal. For tuna themselves, capture and handling cause measurable physiological stress; onboard killing methods vary from immediate spiking (welfare-positive) to ice immersion of live fish (prolonged). Consumer certification schemes like pole-and-line and skipjack-only certifications substantially reduce bycatch welfare harms. These choices are among the most impactful individual seafood decisions for welfare.

What You Can Do

Choose tuna certified as pole-and-line caught from suppliers with low bycatch rates
Avoid tuna from fish aggregating device fleets where bycatch rates are highest
Support import regulations that require bycatch monitoring for all tuna products
Reduce tuna consumption if certified low-bycatch options are unavailable