Discriminant stock structure of Diplodus annularis (Perciformes, Sparidae) in Tunisian waters inferred from saccular otolith morphometry and microchemistry

Authors

1 Laboratory of Ecology, Biology and Physiology of Aquatic Organisms (LR/18/ES/41), Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia

2 Unité de Génétique des Populations et Ressources Biologiques, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunis, Tunisie

3 Laboratory of Ichthyology, University of Montpellier II, P1. E. Battalion, Case 102, 34095 Montpellier, France

4 Department of Zoology, Faculty of Science, Minia University, 61519 El Minia, Egypt

10.22092/ijfs.2024.131964

Abstract

We studied the size dimensions and microchemical structure of the saccular otoliths (sagittae) of two populations of the annular seabream (Diplodus annularis) collected from the Djerba and Kerkennah Islands in Tunisian waters. The goals of our study included (1) measuring the otolith’s length (Lo), width (Wo), surface area (Ao), and perimeter (Po), and evaluating differences in these characteristics and microchemical elements between individuals of D. annularis within each Island, (2) exploring how potential fluctuating asymmetry (FA) in the otolith size affects the stock structure of D. annularis in two Islands, and (3) using these findings to recognize if there were distinct stock structures and connectivity between fish within the two Islands, to develop better-guiding policies for managing and governing the fishery within these Islands. The results revealed significant asymmetry in all size dimensions between the left and right otoliths among males and females within the Djerba and Kerkennah Islands and males and females between the two Islands due to FA. In addition, significant differences in otolith contents of K, Cs, and Pb were found between individuals of the two Islands. The significant asymmetry in otolith size dimensions among males and females of the two Islands due to FA and the noticeable difference in otolith microchemical elements between individuals of the two groups were attributed to some factors, such as fish age, environmental conditions, and fish biological traits. Therefore, the results confirmed the discriminant stock structure and limited connectivity between fish within the two Islands, which should be managed separately.

Keywords

Iranian Journal of Fisheries Sciences
Volume 23, Issue 6
November 2024
Pages 949-969

Files

Share

How to cite

Statistics