Genetic and environmental influences on shape variation in the European sea bass (Dicentrarchus labrax)

This paper demonstrates the contribution of both genetic and environmental effects on cultured European sea bass shape. We used the progeny of five populations of sea bass, in a partly diallel design, to investigate the genetics of shape (estimated with geometric morphometrics) in European sea bass. This was done using a common garden experiment with microsatellite markers assignment to parents and populations to avoid confusion between genetic and environmental effects. Additionally, one of the populations was studied over four different aquaculture facilities to investigate the effects of environment on shape. For the first time in this species, shape-related traits were linked with genetic variation. The first relative warp analysis axis clearly differentiated rearing sites, demonstrating that the main shape/weight effects are related to culturing conditions, thereby accounting for ecomorphologically related differences. The second axis strongly differentiated groups by parental origins; there was a good correlation between shape differences and geographic distances between broodstock sampling locations. High heritabilities of axes scores (0.40–0.55) showed high genetic variation for shape within populations. This study shows that variation in shape has a high genetic component in sea bass, both at the population level and within populations.