Selection against parr maturation in Atlantic salmon

The feasibility of using scale characteristics to detect maturation as parr of anadromous male Atlantic salmon was examined. Smolt age and growth rate were found to be reliable indicators of prior maturation, whereas scale morphology did not differ between maturation phenotypes. Although determination of prior maturation was not 100% efficient, the resulting selection intensities would allow for effective artificial selection against anadromous males which had matured as parr.