The effect of temperature on the energetic growth efficiency of Arctic charr (Salvelinus alpinus L.) from four Swedish populations

The effect of temperature on energy intake, growth and energetic growth efficiency of Arctic charr from four Swedish populations was studied in laboratory experiments. The energy intake and growth curves were functionally similar and consequently, a strongly significant linear relationship between energy intake and growth was found (R2=0.936-0.975). Compared to other salmonids, overall growth efficiency was high, varying between 44.6% and 55.2%. For three populations, growth efficiency decreased linearly with increasing temperature. The effect of temperature was moderate and no optimum temperature for growth efficiency could be estimated. The high growth efficiency of charr and the negative relationship between growth efficiency and temperature suggest adaptation to the harsh environment inhabited by the species.