Welfare Issues in Farmed Atlantic Salmon
By Mark Borthwick
Salmon is the most valuable fish in the world, with a harvest of 2.2 million tonnes of salmon (approximately 1 billion head of fish producing USD $15.4bn annually). Despite a steady improvement in standards and practices in salmon aquaculture over the past two decades, innovative husbandry techniques have been accompanied by new welfare issues.
This paper outlines the main welfare issues in contemporary aquaculture of Atlantic salmon, and identifies areas where further research is required. The main findings are as follows:
Salmon fare particularly poorly in captivity, and do not have a life which the Farm Animal Welfare Council (FAWC) would consider ‘worth living’. Salmon are essentially kept in battery conditions, despite evidence that their quality of life is significantly impacted by current farming practices.
Disease. Pesticide-resistant sea lice present an existential threat to the salmon farming industry, and represent an extinction-level threat to wild salmon populations.
Salmon are obligate carnivores, to which other animals are fed. One third of all caught fish are fed to farmed fish, and salmon are increasingly fed a mixture of soy, caught fish, and poultry meal. This essay estimates that each farmed salmon is fed the equivalent of 9 herring, further compounding welfare issues for animals in the supply chain.
Slaughter methods have been uncritically appropriated from terrestrial animals, and not based upon the best available evidence for humane slaughter of teleost fish.
Species-specific research is required to determine whether the control mechanisms for salmon’s preferred behaviors can be emulated in captivity.