Advanced recirculating aquaculture systems for halibut require specific tank design, water quality parameters, and handling protocols to meet the distinctive welfare needs of this large flatfish species.
Halibut welfare in recirculating aquaculture systems demands species-specific tank design that departs from the vertical swim-through tanks used for round fish like salmon and trout. As flatfish, halibut rest horizontally on the tank bottom, and insufficient bottom area relative to fish biomass creates crowding welfare problems that are not apparent from stocking density calculations based on water volume alone. Water flow must be calibrated to maintain oxygen delivery without dislodging resting fish from their preferred positions. The high value of farmed halibut creates commercial incentives for welfare investment that align with the evidence-based case for lower stocking densities and better environmental management. Progressive halibut RAS operations are developing protocols specifically designed for flatfish welfare rather than adapting round-fish management approaches.