Fish Welfare and Quality in Aquaculture Practices

Increasing demand for farmed fish has spurred innovations in aquaculture that prioritise both the welfare of the animals and the quality of the final product. Welfare considerations span water quality, stocking density, handling procedures and humane slaughter. Stressors such as overcrowding, poor water conditions and rough handling can trigger physiological responses—elevated cortisol, impaired immune function and oxidative stress—that compromise muscle integrity, pH, texture and shelf life. Modern welfare assessment integrates behavioural indicators, physiological metrics and molecular markers to guide management. Novel monitoring tools, coupled with improved stunning and euthanasia techniques, aim to reduce suffering and enhance fillet quality, yielding direct economic and ethical benefits across global production systems.

Research from Nature Portfolio

A new euthanasia method for adult zebrafish employs controlled electrical fields delivered via plate electrodes in standard housing aquaria. When applied at optimised current densities and field strengths, the technique induces irreversible unconsciousness within seconds, achieving consistent kill rates without reliance on chemical anaesthetics. This standardised approach offers a scalable, practical solution for large research colonies and may set a precedent for humane, cost-effective practices in laboratory-based aquaculture species worldwide.

Fish Welfare and Quality in Aquaculture Practices publication trend

The graph below shows the total number of articles in fish welfare and quality in aquaculture practices across all publications each year (not limited to Nature Index journals).

Technical terms

Recirculating aquaculture system (RAS): A closed-loop system that filters and reuses water to maintain optimal rearing conditions.

Stunning: A procedure to render fish unconscious prior to slaughter, minimising pain and distress.

Rigor mortis: Post-mortem stiffening of muscle fibres due to biochemical changes, affecting texture and shelf life.

Cortisol: A stress hormone whose elevation indicates physiological stress and can impact meat quality.

Passive acoustic monitoring: Non-invasive detection of fish stress responses by analysing sound patterns in the rearing environment.

Proteomic profiling: Analysis of protein expression patterns used to identify biomarkers linked to welfare and quality.

References

1. Effects of Stocking Density and Pre-Slaughter Handling on the Fillet Quality of Largemouth Bass (Micropterus salmoides): Implications for Fish Welfare. Foods (2024).
2. Detection of a stress related acoustic signature by passive acoustic monitoring in Atlantic salmon farming. Aquacultural Engineering (2024).
3. Novel euthanasia technique for zebrafish using electric shock in standard group housing aquaria. Scientific Reports (2025).
4. Welfare of rainbow trout at slaughter: Integrating behavioural, physiological, proteomic and quality indicators and testing a novel fast-chill stunning method. Aquaculture (2024).