Whitefishes (genusCoregonus)in Italy: Species distinction and geographic variation

Abstract

Abstract Whitefishes of the genus Coregonus were introduced into northern and central Italian lakes in the second half of the nineteenth century. The lavarello is the most common and is hypothesized to have originated through the hybridization of C. wartmanni and C. schinzi helveticus, and has, for the moment, no precise taxonomic status. A second species, C. macrophtalmus, the bondella, occurs in Lake Como where it is sympatric with the lavarello. Species distinction is reflected by univariate and multivariate consideration of linear measurements and of meristic characters. Moreover, for both these parametres in the lavarello, we found morphometric patterns that distinguish northern from central Italian lake populations. The congruence between the meristic and measurement character systems (analysed independently in the sexes) and their incongruen‐ce with a set of ecological descriptors (water temperature and oxygen content) supports a historical rather than an ecological hypothesis for the causative factor of the geographic variation.