The effect of temperature and ammonia exposure on swimming performance of brook charr (Salvelinus fontinalis)

The effects of water temperature and ammonia concentration on swimming capacity of brook charr (Salvelinus fontinalis, Mitchill, 1814) were determined by measuring gait transition speed (Ugt, cm s− 1), maximum burst speed (Umax, cm s− 1), tail-beat amplitude (a, cm), tail-beat frequency (f, Hz), maximum acceleration of bursts (Amax, cm s− 2), number of bursts, distance of bursts (cm) and total swimming distance (cm) in a 4.5 m long experimental raceway with increasing upstream water velocity. Temperatures other than the acclimation temperature of 15 °C significantly reduced swimming characteristics of gait transition, i.e. Ugt and Amax, while increased ammonia concentration reduced the measures of swimming after Ugt: Umax, the relationship between f and swimming speed above Ugt, a, Amax and the distance travelled with each swimming burst above Ugt. This study, using a novel raceway set-up shows various effects of temperature and ammonia exposure on the swimming performance of brook charr and can be used to establish threshold values for environmental management.