Use of otolith shape to differentiate two lagoon populations of Pagellus erythrinus (Actinopterygii: Perciformes: Sparidae) in Tunisian waters

Abstract

Background. The common pandora, Pagellus erythrinus (Linnaeus, 1758), is widely distributed in the Black and the Mediterranean seas. Therefore, P. erythrinus is a valuable component of the commercial fishery in Tunisia and plays an important role in microeconomics of local areas. The goal of this study was to investigate the stock structure and otolith asymmetry for specimens of the common pandora sampled from two lagoons—Ghar El Melh and Bizerte. Materials and methods. We collected a total of 119 specimens of P. erythrinus from the two lagoons, from May through July 2016. The Elliptical Fourier Analysis (EFA) was determined to evaluate the degree of similarity in the otoliths and detect the reciprocal variability. Results. The Discriminant Factor Analysis for the sagitta shape clearly demonstrated an asymmetry when comparing otoliths (left–right) (P < 0.05) within each population and a difference in shape when comparing the same side between the two populations: between the two sides (right–right and left–left). Conclusion. The comparison of the otolith morphology of the two populations showed a clear difference in shape and a left–right asymmetry of otoliths between and within populations. This result is probably related to genetic and local environmental factors. In fact, this investigation improves the knowledge on the stock discrimination for P. erythrinus and provides useful information for analysing fisheries management of this species in Tunisia.

Keywords

• Pagellus erythrinus
• sagitta
• shape
• asymmetry
• Tu