Flounder: Welfare in European Flatfish Aquaculture

Key Welfare Facts

Flounders are demersal flatfish increasingly trialled in European aquaculture systems as lower-value alternatives.
Flatfish require soft substrate for resting and show stress when denied appropriate bottom conditions.
Territorial behaviour causes competitive exclusion and injury in high-density culture without substrate provision.
Handling for grading and health checks causes extreme flight responses and collision injuries in tank systems.
Water quality management including ammonia and dissolved oxygen is critical as flatfish are highly sensitive.
Slaughter welfare research for flatfish species is less developed than for round fish, representing a knowledge gap.

Welfare Assessment

Flounder welfare in aquaculture requires flatfish-specific housing design including substrate provision and density management. Supporting welfare research specific to flatfish species and advocating for species-appropriate standards prevents unnecessary suffering as this sector develops.

What You Can Do

Support development of flatfish-specific welfare standards and husbandry guidelines
Advocate for substrate provision requirements in flatfish aquaculture licensing
Choose flatfish products from farms with documented welfare assessment and monitoring programmes
Support research into humane slaughter methods appropriate for flatfish species