Original paper

Genetic and morphometric variations in the pikeperch (Sander lucioperca L.) of a fragmented delta

Poulet, Nicolas; Berrebi, Patrick; Crivelli, Alain J.; Lek, Sovan; Argillier, Christine

Abstract

Agricultural development modified the connectivity of the Rhône River delta waterbodies (also called the Camargue) which is now isolated from the Rhône River by dikes. Furthermore, the hydrographic network of the Camargue is constituted of irrigation and drainage canals, which are not directly connected. Pikeperch (Sander lucioperca L.), an allochthonous freshwater species, colonised the Rhône and the Camargue more than 50 years ago. We used morphometric and meristic features, otolith shape descriptors and protein electrophoresis in order to assess whether the Camargue houses one or several pikeperch populations. All characters except the meristic counts highlighted the existence of two subpopulations: one in the drainage network and one in the irrigation network. Electrophoresis showed that the irrigation network population is closer to the Rhône population and that the drainage network population displayed a high inbreeding rate. The causes of such isolation and the implications for the pikeperch population dynamics are discussed.

Keywords

allozymedeltafragmentationmorphometricsotolithpopulation geneticssander lucioperca.