Morphological differentiation of Indian mackerel Rastrelliger kanagurta (Cuvier, 1817) among sampling locations along the Hormozgan coast, Persian Gulf and Gulf of Oman

Articles in Press

Document Type : Original Article

Authors

leila abdoli

Arash Akbarzadeh

Department of Fisheries, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran

10.22067/ijab.2026.99669.1128

Abstract

Morphological variation among fish populations is widely used as an effective tool for stock discrimination and fisheries management. This study investigated morphological differentiation among Rastrelliger kanagurta (Cuvier, 1817) sampling groups collected from four locations along the Hormozgan coast of the Persian Gulf and Gulf of Oman: Jask, Bandar Lengeh, Bandar Abbas, and Qeshm Island. A total of 118 specimens were examined using a truss network system based on 12 homologous landmarks and 26 morphometric characters, together with five meristic traits. Morphometric measurements were adjusted for body size using the allometric transformation of Elliott et al. (1995) prior to statistical analyses. One-way ANOVA revealed significant differences among sampling groups for 12 morphometric and three meristic characters. Discriminant function analysis extracted three canonical functions explaining 100% of the discriminant variation and achieved an overall original classification success of 82.2%, with the highest classification accuracy recorded for the Bandar Lengeh sampling group (96.7%). Wilks’ lambda indicated significant morphological differentiation among sampling groups (P < 0.001). Principal component analysis extracted eight principal components with eigenvalues greater than one, collectively explaining 79.42% of the total morphometric variation. Among the morphometric variables, F22, F16, F15, and F4 showed relatively large effects in the univariate analyses and high loadings in the PCA, while F22, F16, and F15 also contributed strongly to the discriminant functions. UPGMA clustering based on Euclidean distances revealed two major groups, comprising Bandar Abbas–Qeshm Island and Jask–Bandar Lengeh, with the greatest similarity observed between Bandar Abbas and Qeshm Island. Overall, the findings demonstrate measurable morphological differentiation among R. kanagurta sampling groups along the Hormozgan coast, indicating phenotypic structuring among the sampled groups. This morphological differentiation should not be interpreted as definitive evidence of genetically isolated stocks, but may reflect the combined influence of environmental heterogeneity, phenotypic plasticity, and population history. The results provide a useful baseline for future stock assessment and sustainable fisheries management of this commercially important species.

Keywords

Rastrelliger kanagurta

morphological differentiation

truss network morphometrics

morphometric variation

discriminant function analysis

Persian Gulf

Subjects

• Morphology

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