Ascribing sentience to fish: potential policy implications

1. Background

SAWC published a definition of sentience^[1] on 10 February 2021, followed by a paper on principles of ascribing sentience to animals in August 2021^[2]. In this work, SAWC recognised that the threshold for evidence of sentience has been exceeded for vertebrate fish, and thus a consideration of their welfare is important and ethically incumbent upon policymakers.

SAWC also published a case study^[2] considering cephalopods, which has received attention, in conjunction with a London School of Economics report on cephalopod molluscs and decapod crustaceans^[3]. The formal recognition of sentience in these taxa by their inclusion within the scope of the Animal Welfare (Sentience) Act 2022 prompted welcome consideration of the policy implications in relation to these classes of animals. These comparisons have also highlighted the lack of consideration given to the welfare of fish, notwithstanding that they have long been recognised as sentient.

The welfare of fish, as sentient animals, should be a highly relevant consideration for policy makers in Scotland. Trillions of fish are affected by human actions every year worldwide. Scottish vessels landed 429,000 tonnes of sea fish and shellfish in Scotland in 2022 (of which approximately 19,415 tonnes were shellfish) and a further 162 thousand tonnes of sea fish and shellfish abroad^[4]. An estimated 55.3 million salmon smolts were moved for rearing at sea by the aquaculture industry in 2022^[5] Significant numbers of teleosts (a large and diverse group of ray-finned fishes) are sold through the pet trade in the UK each year and are kept by the public. In evidence given to SAWC’s Exotic Pet Working Group in October 2020, the Ornamental Aquatic Trade Association estimated that over one hundred million fish were kept in ponds and aquaria in the UK^[6].

Around half of Scotland’s freshwater and migratory fish species are exploited in recreational angling, with both game and coarse angling seen as important contributors to the Scottish economy. The most valuable sectors include fishing for salmon (Salmo salar), sea trout (S. trutta), brown trout (S. trutta) and rainbow trout (Oncorhynchus mykiss). Coarse fishing for species, such as pike (Esox lucius), perch (Perca fluviatilis), common carp (Cyprinus carpio) and grayling (Thymallus thymallus), has traditionally been a far smaller sector but is becoming increasingly important.

Statutory conservation measures for Atlantic salmon since 2015 now limit the killing of salmon in inland waters. Scottish salmon and sea trout fishery statistics for 2023^[7] reported 32,477 wild salmon caught in the rod fishery, while the total reported rod catch of sea trout was 14,823. Almost all these fish (99% of salmon and 92% of sea trout) were released after capture.

Sea angling is also popular, with around one hundred species caught around the British Isles. Again, the majority (around 80%) of these fish are released^[8].

In both freshwater and sea angling, fish are vulnerable to exposure to painful situations or other impacts on welfare status including injury, stress and mortality^[9]. Negative welfare arises from multiple aspects including tissue trauma from hooks, abrasions and stress from nets, injury from the use of gaffs to control larger fish, stress from capture, handling and exposure to air and a failure to provide a swift and humane method of killing^[10]. Released fish may suffer long-lasting effects or a prolonged death: rates of post-release mortality vary widely according to species and angling techniques employed.