Caracterisation et variation phenotypique et biologique des deux sexes du sandre Sander lucioperca (L., 1758) (teleosteen, Percidae) dans la retenue de barrage de Nebhana (Tunisie centrale)

Abstract

Characterization and phenotypic and biological variation in the two sexes of pikeperch Sander lucioperca (L., 1758) (Teleostei, Percidae) in the Nebhana reservoir (Central Tunisia) ; In order to characterize the difference between the sexes in the pikeperch population (Sander lucioperca (L, 1758)), the phenotypic and biologic variability was estimated in 133 males and 166 females collected from the Nebhana dam. The choice of the meristic and morphometric variables was detected from bibliographical work showing an important rate of variability in marine and fresh water fish. Thus 9 meristic and 23 morphometric characters are retained. The results showed homogeneity of the meristic characters between the males and the females. Therefore, the males differ from the females by 8 morphometric characters in a very significant way to highly significant: total length (LT/LS), fork length (LF/LS), ventral fin length (V/LS), pectoral fin length (P/LS), distance connecting the ventral fin to the anal fin (VA/LS), distance connecting the muzzle to the second dorsal fin (MD2/LS); distance connecting the muzzle to the anal fin (MA/LS), distance connecting the insertion point of the last spine of the first dorsal fin at the end of the caudal fin (PoD/LS) and distance connecting the pectoral fin to the anal fin (PA/LS). The comparative analysis of growth have revealed significant differences between sexes. In fact, the females have higher mean values of total length especially with the most aged individuals. Journal