Looking beyond the Shoal: Fish Welfare as an Individual Attribute

Abstract

Welfare is an individual attribute. In general, providing captive nonhuman animals with conditions conducive to good welfare is an idea more easily applied when dealing with few individuals. However, this becomes much harder—if not impossible—under farming conditions that may imply high numbers of animals living in large group sizes. Although this is a problem inherent to intensive animal farming, it is possibly best exemplified in fish farming, for these practices often rely on extremely high numbers. In this paper we review evidence supporting the notion that fishes are individuals and fish welfare should thus also be considered at the individual level, examine the current state of welfare assessment in the aquaculture industry, evaluate these practices in light of individualized terrestrial animal welfare assessment methods, and make recommendations regarding research that could lead to a better understanding of how to provide each individual fish with good welfare in captivity.

Trait sensitivity to stress and cognitive bias processes in fish: A brief overview

“…Research also suggests that fish exhibit “behavioural syndromes,” essentially personality traits that are correlated with each other (e.g., Conrad et al, 2011 ; Torgerson-White & Sánchez-Suárez, 2022 ). For instance, in zebrafish (e.g., Ariyomo & Watt, 2012 ; Martins & Bhat, 2014 ), stickleback (e.g., Bell & Sih, 2007 ), and guppies (e.g., Smith & Blumstein, 2010 ), a recurring “bold-aggression syndrome” has been observed.…”

“…Furthermore, in fish, the shy-bold dimension is associated with individual variations in both behavioral and physiological responses to stressful stimuli, often referred to as “stress coping styles” (e.g., Castanheira et al, 2017 ; Thörnqvist et al, 2019 ; Torgerson-White & Sánchez-Suárez, 2022 ). These trait variations frequently cluster into two contrasting styles, representing the extremes of a continuous axis.…”

Individuality really matters for fish welfare

“…The authors of the paper Looking beyond the Shoal: Fish Welfare as an Individual Attribute , which was published at Animals Journal last year (Torgerson-White and Sánchez-Suárez 2022 ), reminded us that fishes express considerable individual variation in cognitive abilities, emotions, and preferences, which are linked to personality (Budaev and Brown 2011 ). Despite similar topics were already highlighted before, like in a whole special issue dedicated to the relevance of fish individuality when assessing their physiology, welfare and performance (Gesto et al.…”

“…To make matters worse, this is clearly the case for farm and some lab conditions, like holding tanks. As pointed out in by Torgerson-White and Sánchez-Suárez ( 2022 ), it is much easier to deal with this issue in conditions where fishes are kept under low densities, because this could be comparable to improving the welfare of animals in zoos or under some lab conditions, with just a few fishes per tank, for example.…”

Fish and chips: Using machine learning to estimate the effects of basal cortisol on fish foraging behavior

“…Based on an extensive literature review, Toscano et al ( 2016 ) suggested that these behavioral traits and their interindividual variations can lead to specialization in foraging behavior. Cortisol levels are indeed highly influential on many traits, including immune response (Zhang et al, 2022 ), reproductive investment (Jiang et al, 2022 ), metabolism (Fernandes Silva et al, 2022 ; Winberg and Sneddon, 2022 ), energy reallocation to cope with stressors (Gorissen and Flik, 2016 ), and the behavioral and cognitive responses (Alfonso et al, 2019 , 2020 ; Torgerson-White and Sánchez-Suárez, 2022 ). Furthermore, it is also important to emphasize that in many animal species, basal and post-stress cortisol levels, as well as behavioral responses, are correlated in such a way that these characteristics are used to identify coping styles (Alfonso et al, 2020 ).…”