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 (U(gt), cms(-1)), maximum burst speed (U(max), cms(-1)), tail-beat amplitude (a, cm), tail-beat frequency (f, Hz), maximum acceleration of bursts (A(max), cms(-2)), number of bursts, distance of bursts (cm) and total swimming distance (cm) in a 4.5m long experimental raceway with increasing upstream water velocity. Temperatures other than the acclimation temperature of 15 degrees C significantly reduced swimming characteristics of gait transition, i.e. U(gt) and A(max), while increased ammonia concentration reduced the measures of swimming after U(gt): U(max), the relationship between f and swimming speed above U(gt), a, A(max) and the distance travelled with each swimming burst above U(gt). 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.