Fatigue and Recovery of Blue and Channel Catfish Fingerlings under Flow and No-flow Conditions

Abstract

We compared the ability of fingerling farm-raised channel catfish Ictalurus punctatus and blue catfish I. furcatus to recover from fatigue in flowing and still water by measuring the time course response of plasma lactate, glucose, and cortisol, and muscle lactate concentrations after exhaustive swimming. A prolonged swimming protocol measuring time to fatigue (TTF) was used to compare the recovery ability of fingerling blue catfish (mean ± SE = 27.7 ± 0.3 cm total length [TL]) and channel catfish (27.6 ± 0.2 cm TL). Tested fingerlings were forced to swim at 60 cm/s in a swim tunnel until exhausted and then were allowed to recover either in still water or flowing water. No significant difference was found between flowing and still water recovery for either species. Plasma lactate, glucose, and cortisol, and muscle lactate levels did not differ between fingerling blue and channel catfish at 0 min (immediately after fatigue) or at 30–240 min after fatigue. Although blue catfish fingerlings fatigued more quickly than channel catfish fingerlings (mean TTF = 7.2 ± 0.8 versus 27.6 ± 2.8 min), both species recovered from fatigue in 2–4 h; thus, the time course recovery of plasma cortisol, glucose, and lactate, and muscle lactate metabolites after exhaustive swimming was not significantly different between the two species.