Effects of the Habitat and Genotype on Osteological Traits in Landlocked and Anadromous Ecological Forms of Atlantic Salmon Salmo salar Linnaeus, 1758

Abstract

Studies of speciation and intraspecific differentiation in salmonid fishes are traditionally based on analysis of osteological traits. In the current study the variation of osteological traits was compared between two Atlantic salmon forms: anadromous and landlocked. Each form was represented by three samples: one from a wild population, and two from hatcheries; i.e., we studied six samples in total. In total, 45 osteological characters were analyzed. Differences between the forms were found to be genetically determined to a substantial extent. The factor “origin” explained 48% of the total morphological difference between the fish samples; the factor “habitat”, 32%; and their interaction, 14%. Phenotypic plasticity of the anadromous form was observed to be lower than that of the landlocked form. We consider that the higher phenotypic plasticity may compensate for a decrease in genetic diversity which is observed in landlocked forms of the species.