Shape Changes during the Growth of the Sea Bass, Dicentrarchus labrax (Teleostea: Perciformes), in Relation to Different Rearing Conditions

Abstract

Thin-plate spline regression analysis is applied to sample of sea bass Dicentrarchus labrax, reared at two different salinities, i.e., marine and freshwater, in order to show shape changes and to test statistically morphological differences. All specimens were derived from the same breeding stock and were sampled at five different ages. Centroid size is used as the independent variable in the thin-plate spline regression analysis, and splines at extreme values of centroid size are computed and plotted. Differences in centroid size, for Bookstein’s uniform components (UI and U2) as well as for the pure nonuniform components of shape change are tested for significance. These analyses allow a visualization of allometry and description and testing of significance of the morphological plasticity of the sea bass. In this sense they can be valuable tools in the study of shape change during ontogeny.