Welfare of Wild Turbot and Flatfish in Aquaculture

Flatfish including turbot and halibut are farmed in intensive aquaculture systems with specific welfare challenges related to their unique biology.

Key Facts

Flatfish undergo metamorphosis from upright to laterally flattened body forms
Both eyes migrate to one side of the head during development
They are ambush predators spending much time motionless on the seabed
Turbot aquaculture requires very clean water and high protein diets
Some flatfish show abnormal eye migration in captivity affecting feeding ability

Welfare Considerations

Farmed flatfish experience welfare problems from conditions unsuited to their biology. Developmental abnormalities including incomplete eye migration affect feeding ability and cause chronic disadvantage. High stocking densities force fish onto each other in an unnaturally dense layer on tank bottoms. Poor water quality causes gill disease. Transport and handling stress is significant for fish unaccustomed to being removed from substrate. Their sedentary nature makes enrichment options limited but appropriate substrate and low density are important.

What You Can Do

Choose flatfish from ASC-certified farms with verified welfare standards
Ask seafood suppliers about flatfish farming welfare conditions
Support research into improved welfare standards for farmed flatfish
Reduce consumption of farmed flatfish given ongoing welfare challenges in production