Growth and food consumption of 0+ Arctic charr fed pelleted or natural food at six different temperatures

The effects of temperature and diet on the specific growth rate and food consumption of 1‐summer‐old Arctic charr Salvelinus alpinus were studied. Fish were reared singly in aquaria at six different constant temperatures (5, 9, 13, 16, 18 and 20°C). They were fed Neomysis integer or commercial pelleted food for 2 weeks and growth and food consumption were measured. In both experiments, growth rate increased to an optimum at 15°C. Growth rates were high in the range 13–18°C, with no significant (P >0·05) differences between temperatures. No significant (P> 0·05) differences in growth were found between fish at 9 and 20°C. There were no effects of diet on size‐adjusted growth rates. The growth efficiency decreased with increasing temperature in both treatments, but the decrease was faster in the Neomysis treatment. Charr seemed to compensate for the high water content (79·5%) of Neomysis by having a higher food intake.