Continental and ecological variance components of European and North American Atlantic salmon (Salmo salar) phenotypes

Juvenile Atlantic salmon (Salmo salar) meristic and morphometric characteristics were examined from 47 European and North American river populations. The relative importance of continental origin, stream gradient, overall temperature regime, and seasonal temperatures in explaining the phenotypic variation of these populations was evaluated using multi-way ANOVA. Ecological factors explained a greater percentage of the variance than continental origin for both meristic and morphometric characters. Stream gradient was the most important factor explaining morphometric variation and April-May mean temperature was the most important factor explaining meristic variation.