Patagonian Toothfish Welfare in Southern Ocean Fisheries

Patagonian toothfish, sold as Chilean sea bass, is caught in the deep Southern Ocean with welfare considerations for these slow-living deep-water fish during capture and handling.

Key Facts

Patagonian toothfish live at depths of 300-2,500 metres in the Southern Ocean
The species is long-lived, growing slowly and reaching over 200 kg and 50 years of age
MSC-certified longline fisheries target the species with reduced bycatch compared to trawl methods
Barotrauma from rapid ascent to surface during capture causes physical damage to swim bladder and internal organs
The Marine Stewardship Council certifies some fisheries for sustainability but welfare standards are separate from sustainability criteria

Welfare Considerations

Patagonian toothfish caught on longlines experience barotrauma as they are hauled from depth, with rapid pressure reduction causing expansion of the swim bladder and potential internal organ damage. Fish with severe barotrauma cannot survive return to depth and must be killed at the surface. The welfare of fish during the haul process — which may take several hours from depth — and subsequent handling and killing on deck is largely unmonitored. As a deep-dwelling, slow-moving species, toothfish may experience significant physiological stress during capture and ascent. Welfare monitoring and humane killing requirements for deep-water fisheries lag significantly behind those developing for aquaculture species.

What You Can Do

Choose MSC-certified Patagonian toothfish as a sustainability baseline when purchasing
Advocate for welfare criteria to be incorporated alongside sustainability in MSC and equivalent certification standards
Support development of welfare guidelines for deep-water fisheries where barotrauma is a significant welfare issue
Reduce consumption of slow-lived, deep-water species as a broader sustainability and welfare strategy