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Hvas M, Folkedal O, Oppedal F
What is the limit of sustained swimming in Atlantic salmon post smolts?
Atlantic salmon aquaculture is expanding into offshore sites susceptible to extreme weather. Strong and persistent water currents in these farm environments may compromise fish welfare if swimming capacities are exhausted. We assessed sustained swimming limits with regards to both speed and time in Atlantic salmon of ~700 g and ~39 cm. Based on a percentage of the critical swimming speed, sustained swimming trials were performed at constant speeds until fish fatigued or 72 hours had passed. Impressively, most fish were able to sustain 80–85% of the critical swimming speed for 72 consecutive hours. However, at higher speeds fatigue was reached within the first 2 hours. These results add novel insights in environmental limits and fish welfare implications in exposed aquaculture.