Welfare issues for farmed fish
In fish farms, large numbers of fish are confined in a small area which can cause serious welfare problems. Salmon as big as three-quarters of a metre long can be given the equivalent of as little as a bathtub of water each.
Limited room as they grow
Overcrowded fish are more susceptible to disease and suffer more stress, aggression, and physical injuries such as fin damage. Along with lack of space, overcrowding can also lead to poor water quality, so the fish have less oxygen to breathe.
Rearing fish in cages prevents their natural swimming behaviour. Fish like salmon would naturally swim great distances at sea. Instead, the fish swim in circles around the cage, rubbing against the mesh and each other.
Atlantic salmon and rainbow trout are often starved for several days before slaughter to empty the gut. Only one or two days are needed, but fish can be starved for two weeks or more.
Suffocated in air or on ice
Farmed fish are slaughtered by a range of different methods. Some methods are more humane such as electrical stunning or a strike to the head. Other methods cause greater suffering, such as leaving the fish to suffocate in air or on ice, gassing with carbon dioxide or cutting the gills without stunning.
There are alternatives to intensive farming of fish with much higher welfare potential.