Evaluation of otolith shape as an approach to stock discrimination of Mugil cephalus (Linnaeus, 1758) in the lagoon environments of Benin

Abstract This study explores the ecological diversity of otoliths in Mugil cephalus by analysing data from 190 individuals collected at different sites, including the Porto Novo lagoon, the Cotonou lagoon and Lake Nokoué. The results revealed significant differences in otolith morphology, showing significant associations with the biological characteristics of the fish at each site. Analysis of the asymmetry between the right and left sides reveals distinctions between these two aspects. There is a significant structuring of stock units according to otolith shape, with marked differences between the different geographical sampling areas. The asymmetry percentages illustrate marked differences between the study sites, suggesting variations in the impact of environmental factors on otolith morphology. The higher asymmetry percentages observed in the Porto-Novo lagoon and the Cotonou lagoon indicate a different morphological response compared to Lake Nokoué, which could be attributable to distinct environmental conditions and specific selective pressures.