Work

Tank- and cage-farmed Atlantic salmon display similar swimming performance and appetite recovery despite differences in gill and heart morphology

Year: 2025

Type: article

Abstract: Understanding Atlantic salmon physiology is essential for ensuring welfare in aquaculture. Many physiological studies used to establish welfare thresholds have relied on fish reared in controlled tank settings, yet commercial production occurs in more variable sea cage environments. This raises the question of whether tank-reared salmon serve as reliable models for performance and health assessments of sea cage-reared populations. We compared swimming performance, stress recovery, and morphology between two groups of farmed Atlantic salmon: one reared entirely in tanks and another transferred to sea cages at ~100 g, where they remained for 8 months. Both groups displayed comparable swimming performances and similarly regained appetite within 1 week following an exhaustive stressor, with no post-exercise mortality. However, sea cage-reared salmon had a slower appetite recovery trajectory and minor welfare impairments, suggesting more challenging recovery conditions at sea. Morphological analysis revealed potential trade-offs in gill and heart health: tank-reared salmon had signs of healthier gills but a higher incidence of deviating heart morphology. Unexpectedly, salmon with rounder heart ventricles and more obtuse ventricular bulbus angles swam faster relative to their body size, challenging previous findings and underscoring the need for further investigation into the functional significance of heart morphology. Our results highlight the resilience of sea cage-reared salmon and affirm the role of laboratory studies in aquaculture research, especially when complemented by site-specific assessments to bridge experimental and commercial contexts.

Source: Aquaculture

DOI: 10.1016/j.aquaculture.2025.742826

Authors: André Morin, Tim Dempster, Fletcher Warren-Myers, Ida B. Johansen, Frode Oppedal, Malthe Hvas

Institutions: Deakin University, Norwegian University of Life Sciences, Norwegian Institute of Marine Research

Language: English

Topic: Aquaculture disease management and microbiota

Subfield: Immunology

Field: Immunology and Microbiology

Domain: Life Sciences

SDG: Life below water

Open Access status: hybrid

Estimated APC paid: $3,910