Cognitive appraisal of environmental stimuli induces emotion-like states in fish

Abstract

The occurrence of emotions in non-human animals has been the focus of debate over the years. Recently, an interest in expanding this debate to non-tetrapod vertebrates and to invertebrates has emerged. Within vertebrates, the study of emotion in teleosts is particularly interesting since they represent a divergent evolutionary radiation from that of tetrapods, and thus they provide an insight into the evolution of the biological mechanisms of emotion. We report that Sea Bream exposed to stimuli that vary according to valence (positive, negative) and salience (predictable, unpredictable) exhibit different behavioural, physiological and neuromolecular states. Since according to the dimensional theory of emotion valence and salience define a two-dimensional affective space, our data can be interpreted as evidence for the occurrence of distinctive affective states in fish corresponding to each the four quadrants of the core affective space. Moreover, the fact that the same stimuli presented in a predictable vs. unpredictable way elicited different behavioural, physiological and neuromolecular states, suggests that stimulus appraisal by the individual, rather than an intrinsic characteristic of the stimulus, has triggered the observed responses. Therefore, our data supports the occurrence of emotion-like states in fish that are regulated by the individual’s perception of environmental stimuli.

A Proteomics and other Omics approach in the context of farmed fish welfare and biomarker discovery

“…The recent insights about how fish are far more complex organisms than previously thought (Cerqueira et al . ) and that there are enough molecular‐based commonalities between fish and mammals (Schartl ) endures the statement from (Mejdell et al . ) to include these taxa within national welfare legislation worldwide.…”

“…) and can express emotions‐like states (Cerqueira et al . ). Recently, in zebrafish ( Danio rerio ), the capacity of expressing emotional fever (e.g.…”

“…; Cerqueira et al . ). Consequently, not homeostasis but allostasis is at the basis of the new animal welfare concept.…”

“…; Cerqueira et al . ) and the capacity to scientifically assess animal affective perception should induce the expansion of ground‐breaking farming practices based on animals’ sentience and their cognitive skills, in order to truly improve their psychological welfare. Psychological stressors like predictability, controllability, pleasantness or novelty, are being used to understand the way fish perceive environmental stimuli, the affective value they attributed to them and how they impaired fish welfare (Xu et al .…”

“…The recent insights about how fish are far more complex organisms than previously thought (Cerqueira et al 2017) and that there are enough molecular-based commonalities between fish and mammals (Schartl 2014) endures the statement from (Mejdell et al 2007) to include these taxa within national welfare legislation worldwide. Before that, the EU, Council Directive 98/58/EC have set minimum standards for the protection of animals reared or kept under farming purposes, including fish.…”