Effect of social interactions on growth rates and conversion efficiency of Arctic charr, Salvelinus alpinus L.

Mixing of fish from size‐graded groups did not have detrimental effects on subsequent growth performance as compared with control groups. Coefficients of variance for size, within each population, increased with time demonstrating that social interactions were influencing the growth rates of some individuals. Rates of growth of large fish were higher than those of small indicating the growth of the small fish was suppressed below its potential maximum. The results are discussed in relation to those of previous studies and it is concluded that inferences drawn from changes in coefficients of variance have frequently been incorrect.