Table 1.

Kinematic and hydrodynamic properties of fins during steady swimming and manoeuvres of brook trout

Kinematic excursion (mm)Maximum trailing edge velocity (cm s-1)Maximum lateral jet velocity (cm s-1)Maximum angle of attack (deg.)Body heave frequency (Hz)Heave to chord ratio (h0/c)Pitch (deg.)Phase angle ψ (deg.)Strouhal number (St)
Steady swimming at 0.5 L s-1
   Dorsal fin11.6±0.653.4±2.818±221.00±1.002.2±0.10.3±0.0215.0±1.138.9±2.80.3±0.02
   Anal fin9.3±0.251.2±1.918±228.50±0.782.1±0.21.2±0.0511.1±0.638.6±1.10.2±0.01
   Dorsal body1.9±0.2
   Anal body4.6±0.3
Steady swimming at 1.0 L s-1
   Dorsal fin10.1±0.577.8±4.013±218.38±0.912.9±0.30.4±0.0212.1±0.834.7±1.30.2±0.01
   Anal fin9.9±0.367.7±3.318±232.00±1.002.9±0.31.7±0.0615.0±0.628.0±0.70.2±0.01
   Dorsal body2.3±0.3
   Anal body6.4±0.7
Manoeuvres at 0.5 L s-1
   Dorsal fin10.4±1.147.0±2.516±326.83±1.963.5±0.80.5±0.0819.7±1.80.2±0.03
   Anal fin9.6±0.751.1±2.618±233.94±2.182.5±0.41.2±0.116.3±1.40.2±0.02
   Dorsal body4.8±0.2
   Anal body9.4±0.5
  • Values are means ± s.e.m.

    For kinematic variables, N>40 (a minimum of 10 half tailbeats for each of four fish at each speed)

    For hydrodynamic variables, N>5 (a minimum of 5 half tailbeats for each of four fish at each speed)

    Kinematic excursion is measured from peak lateral excursion on one side to peak lateral excursion on the other side of the fish

    ψ is the phase lag between fin heave and pitch. Fin heave is defined by the oscillation of the body at the point of fin attachment

    St = fA/U, where f is heave frequency, A is kinematic excursion and U is swimming speed