Length-Weight Relationship and Sagittal Otolith Morphometrics of Diplodus sargus (Linnaeus, 1758) from the Southwestern Mediterranean Sea: Using Multiple Analytical Approaches

MANSOURI, Toufik; Guendouzi, Yassine; Djezzar, Miliani; Stransky, Christoph; Brückner, Hendrik; Rohlf, Norbert

doi:10.21608/ejabf.2025.427182.6648

Length-Weight Relationship and Sagittal Otolith Morphometrics of Diplodus sargus (Linnaeus, 1758) from the Southwestern Mediterranean Sea: Using Multiple Analytical Approaches

Document Type : Original Article

Authors

¹ ERP (Eau, Roches & Plantes) Laboratory, Djilali Bounaama University of Khemis Miliana, Algeria.

² Laboratory for the Management and Valorization of Agricultural and Aquatic Ecosystems, University Center of Tipaza Morsli Abdallah, Ouade Merzouk 4200, Tipaza, Algeria.

³ ERP (Eau, Roches & Plantes) Laboratory, Djilali Bounaama University of Khemis Miliana, Theniet El Had Road, Soufay 44225 Khemis Miliana, Algeria.

⁴ Thünen Institute of Sea Fisheries, Bremerhaven, Germany.

10.21608/ejabf.2025.427182.6648

Abstract

This study investigated the length-weight relationship and morphometric characteristics of sagittal otoliths of Diplodus sargus (Linnaeus, 1758), including contour shape analysis, using multiple analytical approaches. These approaches aim to characterize the otoliths' outlines and to explore their potential as a tool for biological and ecological discrimination. A sample of 102 D. sargus individuals was collected from fisheries in three locations representing different coastal regions of Algeria: Mostaganem (western coast), Tipaza (central coast), and Jijel (eastern coast). A significant positive correlation (R² = 0.67; P < 0.05) between total length (TL) vs. total weight (TW) was revealed. Isometric growth between length and weight was recorded in D. sargus individuals (P> 0.05). Significant inter-station differences in TL and TW indicated spatial heterogeneity in population structure. A morphometric analysis based on weight and shape indices was applied to assess the structural variability of the otoliths. No significant differences were detected between the two sagittal otoliths in terms of weight and morphometric parameters (P> 0.05: Wilcoxon test and paired t-test). Furthermore, contour analysis of the right sagittal otolith using the wavelet method revealed significant shape variation, particularly in D. sargus sampled from Mostaganem. This variation may reflect the influence of environmental and/or genetic factors on otolith contour morphology in this region.

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