Species: Trout

Quantifying the welfare impact of air asphyxia in rainbow trout slaughter for policy and practice

C. Schuck-Paim, W.J. Alonso, P.A. Pereira, J.L. Saraiva, M. Cerqueira, C. Chiang & L.U. Sneddon

Published in 2025

Study using the Welfare Footprint Framework to quantify the effectiveness of slaughter practices used on trout, by measuring the time spent by the fish in negative affective states. The study shows that electrical or percussive stunning can significantly reduce pain, providing evidence-grounded metrics to guide regulatory decisions.

Document Types: Scientific paper

Animal categories: Fish

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A Guide on Fish Welfare in Spanish Aquaculture - Volume 4: Welfare of rainbow trout

APROMAR

Published in 2025

Guide published by the Spanish aquaculture industry, describing the good practices to ensure rainbow trout welfare. It proposes specific indicators appropriate to each farming phase, while emphasizing the importance of training, sustainability and a stronger legal framework.

Document Types: Good practice guide

Animal categories: Fish

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Effects of electrical and percussive stunning on neural, ventilatory and cardiac responses of rainbow trout

Jeroen Brijs, Per Hjelmstedt, Erika Sundell, Charlotte Berg, Erik Sandblom, Albin Gräns

Published in 2025

Study evaluating the effectiveness of dry and percussive electrical stunning for the ethical slaughter of rainbow trout. The results indicate that percussivestunning is more effective, while dry electrical stunning requires further research before it can be validated as a humane slaughter method.

Document Types: Scientific paper

Animal categories: Fish

Keywords:Animal-based measurements, Consciousness, Pain, Euthanasia, Brain integration

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Air bubble curtain improves the welfare of captive rainbow trout fry and fingerlings

Océane Amichaud, Thomas Lafond, Georgina Lea Fazekas, Aude Kleiber, Thierry Kerneis, Axel Batard, Lionel Goardon, Laurent Labbé, Sophie Lambert, Sylvain Milla, Violaine Colson

Published in 2024

Scientific article showing that the repeated diffusion of bubbles in a tank improved the welfare of rainbow trout. The short-term (~7 weeks) and long-term (~21 weeks) enrichment effects were similar to those observed with more conventional environmental enrichment (provision of plants and shelter). The fish were less aggressive, less fearful and showed enhanced learning abilities.

Document Types: Scientific paper

Animal categories: Fish

Keywords: Animal-based measurements, Adaptation of the environment to the animal, Learning, training, Enrichment, Wefare indicators, Housing, Living environment, Behavioural disorders, Stress

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Feeding predictability as a cognitive enrichment protects brain function and physiological status in rainbow trout: a multidisciplinary approach to assess fish welfare

A. Kleiber, J. Roy, V. Brunet, E. Baranek, J.M. Le-Calvez, T. Kerneis, A. Batard, S. Calvez, L. Pineau, S. Milla, V. Guesdon, L. Calandreau, V. Colson

Published in 2024

Scientific article showing that the feeding predictability contributes to cognitive enrichment, offering a way to improve the welfare and immune status of rainbow trout.

Document Types: Scientific paper

Animal categories: Fish

Keywords:Adaptation of the environment to the animal, Aggression, Aggressiveness, Enrichment, Welfare indicators, Stress

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Environmental enrichment improves cognitive flexibility in rainbow trout in a visual discrimination task: first insights

Valentin Brunet, Thomas Lafond, Aude Kleiber, Léa Lansade, Ludovic Calandreau, Violaine Colson

Published in 2023

Scientific article studying the impact of environmental enrichment on the cognitive abilities of rainbow trout as a model aquaculture species. Using an operant conditioning device, after an acquisition phase in which the fish learned to discriminate between two colors, they all successfully completed four inversion learning tasks, demonstrating the cognitive flexibility of rainbow trout. They all passed the generalization task. Fish raised in an enriched environment performed better in the acquisition phase and in inversion learning.

Document Types: Scientific paper

Animal categories: Fish

Keywords: Learning, training, Enrichment, Memory, Cognitive processes

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