Sole and turbot are flatfish species increasingly farmed in European marine aquaculture, with distinct welfare challenges arising from their benthic lifestyle and stocking requirements.
Flatfish welfare presents unique challenges because these species spend their lives on the seabed and have specific space and substrate requirements. High stocking densities in rectangular tanks cause social stress, competition and fin biting. Turbot in particular are cannibalistic at high densities and under nutritional stress. Sole are sensitive to water quality and show immune suppression under poor conditions. Optimal welfare requires appropriate tank design with flat substrate, suitable stocking densities and excellent water quality management.