Figures (2)  Tables (1)

    • Figure 1. 

      Schematic representation of two classical swimming flume designs: (a) Blazka-type, and (b) Brett-type.

    • Figure 2. 

      Conceptual framework illustrating the potential application of critical swimming speed (Ucrit) in offshore aquaculture. Ucrit-based applications include site selection and adaptation to offshore farming environments, where swimming performance should be considered together with hydrodynamic conditions to optimize farming environments and ensure fish welfare.

    • Species Length (cm) Water
      temperature (°C)      		 Acclimation Protocol Time increment Velocity increment Reported Ucrit Apparatus Ref.
      Sockeye salmon Total length: 18.8 cm 15 12–14 h at 0.1 ft·s−1 Step-Ucrit 60 min 0.3 ft·s−1 2.5 ft·s−1 Brett tunnel Brett, 1964[15]
      Sockeye salmon Total length: 18.5 cm 24 12–14 h at 0.1 ft·s−1 Step-Ucrit 60 min 0.3 ft·s−1 2.3 ft·s−1 Brett tunnel Brett, 1964[15]
      Rainbow trout 12.5 cm (not specified) 22.6 2–20 h at 2-4 cm·s−1 Step-Ucrit 20 min 9 cm·s−1 79.3 cm·s−1 Brett type Jones, 1971[22]
      Largemouth bass Fork length: 10.4 cm 25 12 h at 20 cm·s−1 Step-Ucrit 60 min 20 cm·s−1 30.0 cm·s−1 Brett type Farlinger & Beamish, 1977[23]
      Largemouth bass Fork length:10.4 cm 25 12 h at 20 cm·s−1 Step-Ucrit 5 min 10 cm·s−1 50.0 cm·s−1 Brett type Farlinger & Beamish, 1977[23]
      Rainbow trout Fork length: 38.9 cm 5.5−8 21 h at 10 cm·s−1 Ramp-Ucrit 5–6 min to 75% Ucrit, then 30 min
      at 7.8 cm·s−1 (0.2 BL·s−1)      		 63.8 cm·s−1 Brett type Jain et al., 1997[24]
      Rainbow trout Not given
      (body mass 446.0 g)      		 11−13 1 d before test Ramp-Ucrit Every 1 min increments of 5 cm·s−1 to ramp
      fish to 50% Ucrit, then 20 min at 10 cm·s−1      		 63.5 cm·s−1 Brett type Farrell, 2008[25]
      Atlantic salmon Fork length: 35.8 cm 3 Overnight at 15 cm·s−1 (~0.45 body lengths·s−1) Step-Ucrit 30 min 15 cm·s−1 74.8 cm·s−1 Brett type Hvas et al., 2017[30]
      Atlantic salmon Fork length: 35.1 cm 13 Overnight at 15 cm·s−1 (~0.45 body lengths·s−1) Step-Ucrit 30 min 15 cm·s−1 91.3 cm·s−1 Brett type Hvas et al., 2017[30]
      Atlantic salmon Fork length: 36.0 cm 23 Overnight at 15 cm·s−1 (~0.45 body lengths·s−1) Step-Ucrit 30 min 15 cm·s−1 84.9 cm·s−1 Brett type Hvas et al., 2017[30]
      Rainbow trout Total length: 20.4 cm 12.2 Overnight at 3.60 cm·s−1 Ramp-Ucrit Every 5 min increments of 5 cm·s−1 to
      50% Ucrit, then 5 cm·s−1 every 15 min      		 67.8 cm·s−1 Brett type McCaffrey, 2020[26]
      Nile tilapia Body length: 7.2 cm 28.3 1 h at 0 cm·s−1 Step-Ucrit 30 min Not given 69.1 cm·s−1 Brett type Mengistu, 2021[31]
      Large yellow croaker Body length: 4.3 cm 26 30 min at 3 cm·s−1 Ramp-Ucrit Every 5 min increments of 3 cm·s−1 to
      50% Ucrit, then 5 cm·s−1 every 15 min      		 10.8 cm·s−1 Circular swimming arena Zeng et al., 2022[7]
      Spotted sea bass Body length: 7.3 cm 18 30 min at 10 cm·s−1 Ramp-Ucrit Every 5 min increments of 5 cm·s−1 to
      50% Ucrit, then 10 cm·s−1 every 15 min      		 41.8 cm·s−1 Flow-controlled recirculating flume Li et al., 2025[11]

      Table 1. 

      Summary of reported critical swimming speed (Ucrit) and measurement protocols across fish species.