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Many types of fish and shellfish are farmed in Canada, with Atlantic salmon and trout being two of the largest of the commercial industries. Aquaculture is carried on in almost every province and the Yukon.
In 2020, Canada’s aquaculture finfish production volume was 140,775 tonnes. Of the total 2020 aquaculture (finfish and shellfish) of 170,805 tonnes, salmon represented 74.5%, trout 6.1%, and other finfish (e.g. sturgeon, tilapia, sabelfish, cod, halibut) 0.8%.
Some fish species, such as Arctic charr, are farmed in tanks (land-based); others are contained in marine net pens. Young fish are transferred from Canadian hatcheries to these farms. To give one example of feeding requirements, salmon are fed dry pellets comprised of fish meal, fish oil and plant proteins and require 1 Kg. of feed for each Kg. of weight gain and “0.4 Kg. of wild fish meal and oil are needed to grow 1 Kg. of farmed salmon”- see the Species Index . Diseases and parasites are two health matters that must be managed.
Different species of finfish have different welfare needs. As part of the process of developing the national guidelines set out in the 2021 Code of Practice for the Care and Handling of Farmed Salmonids, priority welfare needs were identified by a Scientific Committee from its review of scientific literature. Its report starts by discussing the question of fish sentience and recommends that producers take a “prudent approach” to reduce physiological and behavioural responses “that could result in conscious pain or other negative affective states whenever possible” (see CODE OF PRACTICE FOR THE CARE AND HANDLING OF FARMED SALMONIDS: REVIEW OF SCIENTIFIC RESEARCH ON PRIORITY ISSUES at page 1), and then highlights specific welfare matters related to: rearing, at different life stages (e.g. effect of light duration and intensity; density of fish in a confined space; enrichments for positive welfare); feeding – the welfare impact of feed withdrawal (e.g. used prior to slaughter to purge fish flesh of an “off taste” caused by bacteria); sea lice (e.g. the health and welfare impacts of infestation, and of mechanical, chemical and non-chemical methods to control sea lice); ice-slurry slaughter method (which likely causes death by asphyxiation and which the Code requires to be phased out by producers as soon as possible and no later than Jan.1, 2025); and various other topics related to welfare such as pain control for tagging and fin-clipping, emergency euthanasia during transport, and indicators of stress. Acute stress can be caused by procedures such as transport, grading, and handling, whereas chronic stressors can include crowding, poor water quality, toxins in feed, and hierarchical aggression by other fish. A second committee, the Code Development Committee, summarized its response to the five “top-of-mind concerns” identified through a public survey.
For comparison, one can review Global Animal Partnership’s farmed salmon welfare certification standards. Standards for Salmon
For a discussion of the extent to which the life of a farmed fish falls short of the globally recognized Five Freedoms of Animal Welfare for preserving both physical and mental welfare, see Part III of this article by Bradley Varner (2022, Animal Legal & Historical Center, Michigan State University).
Of further interest is the comprehensive guide titled Key Aquatic Animal Welfare Recommendations for Aquaculture produced by the Aquatic Life Institute (founded in 2019 to focus on coordinating aquatic animal welfare advocacy internationally) along with its global Aquatic Animal Coalition.
And in addition to the welfare concerns for every farmed fish, the nature of marine net pen aquaculture raises concerns about the escape of farmed fish into wild populations, transfer of pathogens between farmed and wild populations, and the impact on the surrounding environment.