Work

Preferred and Optimal Swimming Speeds in Rainbow Trout (Oncorhynchus mykiss) at Three Temperatures

Year: 2025

Type: article

Abstract: Sustained exercise in aquaculture is known to improve the health and growth of finfish. Implementing exercise regimes has become an increasing focus in aquaculture practice. This study examined the relationship between the preferred swimming speed (Upref) and the optimal swimming speed (Uopt) in rainbow trout (Oncorhynchus mykiss) under non-migratory conditions typical of aquaculture environments. Using a circular raceway, rainbow trout were allowed to swim voluntarily to determine Upref. Uopt was measured using a forced-swimming test in a swim tunnel respirometer. Experiments were conducted at three temperatures (10 °C, 15 °C, and 20 °C). The results revealed a significant difference between Upref (1.18 ± 0.14, 1.17 ± 0.19, and 1.24 ± 0.15 BL s−1, respectively) and Uopt (1.4 ± 0.19, 1.5 ± 0.15, and 1.6 ± 0.24 BL s−1, respectively) across all temperatures. Aerobic scope was greatest at 15 °C (3.8), consistent with the species’ thermal range. Notably, swimming at Upref required 18–22% less energy than Uopt, suggesting that Upref is more suitable for aquaculture systems. This study introduces a minimally invasive and stress-free method for determining Upref and provides insights that can optimize flow regimes in aquaculture tanks, improving both energy efficiency and fish welfare.

Source: Fishes

DOI: 10.3390/fishes10020064

Authors: Ólavur av Fløtum Mittún, Morten Bo Søndergaard Svendsen, Lars Emil Juel Andersen, Heiðrikur Bergsson, John Fleng Steffensen

Institutions: University of Copenhagen, Technical University of Denmark

Language: English

Topic: Physiological and biochemical adaptations

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,137

Funders: Københavns Universitet, Grønt Udviklings- og Demonstrations Program