Atlantic and Pacific halibut are among the largest farmed flatfish species. Their unique biology and welfare needs differ substantially from round-bodied fish and require specialized aquaculture management.
Halibut welfare in aquaculture presents challenges specific to their benthic flatfish biology. Unlike round-bodied salmon or trout, halibut spend much of their time resting on the substrate — tank designs that fail to provide adequate bottom area relative to fish numbers prevent this fundamental behavioral need. The juvenile metamorphosis period, during which halibut transition from symmetrical larvae to asymmetrical benthic adults with both eyes on one side, is welfare-sensitive and requires appropriate environmental conditions and nutrition for successful development. Cannibalism in juvenile stages necessitates careful size-grading — a handling stress in itself — to prevent welfare harm from intraspecific predation. At slaughter, halibut require the same consideration as other farmed fish for humane killing methods. Their large body size makes percussive or electrical stunning technically more complex than for smaller species.