Table 1.

Cardiorespiratory parameters for sockeye salmon at rest, swimming at 1.35 BL s–1 and during recovery

Resting at 15°CSwimming at 15°CFatigue at 21–24°CRecovery at 15°C
O2 (μmol min–1 kg–1)56.3±3.1a (15)365.6±18.8b (15)453.1±12.5c (13)93.8±9.4d (14)
(ml min–1 kg–1)25.3±1.8a (13)58.0±2.2b (12)67.8±2.8c (11)33.8±2.1d (13)
fH (beats min–1)65.2±2.5a (12)81.4±1.7b (13)104.5±2.6c (11)82.0±1.3b (13)
Vs (ml beat–1 kg–1)0.38±0.03a (12)0.69±0.03b (11)0.63±0.04b (11)0.41±0.03a (13)
PaO2 (Torr)97.3±6.1a (11)74.4±6.3b (11)102.0±4.4a (10)101.3±5.1a (12)
PvO2 (Torr)36.9±3.6q* (7)21.9±2.8r* (5)27.5±2.9r* (5)41.9±3.0q* (7)
CaO2 (μmol ml–1)6.59±0.38a (7)5.22±0.34b (7)5.54±0.22b (7)6.08±0.25ab (7)
CvO2 (μmol ml–1)4.80±0.40a* (5)2.21±0.17b* (5)1.11±0.09c* (5)3.71±0.44a* (5)
TaO2 (μmol min–1 kg–1)163.4±15.8a (7)314.1±21.4b (7)358.5±12.5b (7)200.9±20.7a (7)
AV̇O2 (μmol ml–1)1.29±0.24a (3)2.99±0.44b (5)4.76±0.48c (5)2.57±0.26b (5)
pHa7.74±0.05ac (9)7.67±0.03ab (9)7.62±0.02b (9)7.78±0.02c (9)
pHv7.74±0.05q (5)7.65±0.04qrs (5)7.54±0.02r* (5)7.73±0.04qs (5)
Hct a (%)30.0±1.5a (13)31.4±1.4a (14)32.0±1.8a (12)30.4±1.6a (14)
Hct v (%)28.9±0.7q (9)31.1±0.8q (8)30.9±0.9q (6)29.3±2.0q (8)
Hb a (mg ml–1)107.1±8.1a (11)104.8±12.9a (12)118.5±7.9a (8)102.3±4.6a (10)
Lactate (mmol l–1)1.9±0.3a (9)3.0±0.4ac (9)5.5±0.5b (9)4.0±0.6c (9)
Potassium (mmol l–1)3.9±0.5a (7)5.1±0.5a (7)7.4±0.5b (7)5.6±0.7ab (7)
Cortisol (ng ml–1)45.2±5.6a (11)206.3±25.3b (12)559.6±25.5c (11)271.3±41.6b (10)
  • Fish fatigued at different temperatures ranging from 21–24°C (see Fig. 1) and the measurements presented were taken at the temperature when fatigue occurred. Values are means ± s.e.m., and N-values are presented in brackets. Different letters indicate significant differences within groups and * indicates a significant difference between arterial and venous blood samples. O2, metabolic rate (rate of O2 consumption); , cardiac output; fH, heart rate; Vs, cardiac stroke volume; PaO2, partial pressure of O2, arterial; PvO2, partial pressure of O2, venous; CaO2, O2 concentration of arterial blood; CvO2, O2 concentration of venous blood; TaO2, arterial O2 delivery; AV̇O2, arteriovenous O2 delivery (O2 extraction); pHa, pH of arterial blood; pHv, pH of venous blood; Hct a, haematocrit, arterial; Hct v, haematocrit, venous; Hb a, haemoglobin, arterial