Molecular investigation of key commercial fish species from the Eastern Atlantic Ocean, Ghana: genetic diversity and phylogenetic relationships

Abstract

Prior to this research, ichthyologists and conservationists in Ghana had limited genetic data on indigenous marine fish species, which is essential for their effective management and utilization in the development of scientifically informed aquaculture practices at the national level. Hence, the current research investigates the genetic diversity and population structure of ten commercially important 10 fish species from the eastern Atlantic, using the mitochondrial COI gene as a genetic marker. DNA sequences generated (n=10) in this study were compared to GenBank entries (n=138), showing a high similarity (98%-100%) across all species. The estimated mean inter-species genetic distances varied, with the highest (35.29%) between Pagellus bellottii and Cynoglossus senegalensis. Haplotype network analysis revealed unique haplotypic diversity among Ghanaian specimens, with occasional regional haplotype sharing. However, some distinct haplotypes spread across distant populations suggesting possible phylogeographic differentiation due to geographic isolation. Phylogenetic analysis using Bayesian inference revealed distinct clades for each species, supporting their monophyletic grouping within respective family lineages. Notably, high intra-species genetic distances and haplotype diversity in Chloroscombrus chrysurus, C. senegalensis, Dentex angolensis, Priacanthus arenatus, and Pseudotolithus senegallus suggest the presence of potential cryptic diversity in these marine species, warranting further confirmation through combined morphological and genetic studies. These findings highlight DNA barcoding as a critical tool in systematics, conservation genetics, and sustainable fisheries management, underscoring the need for a comprehensive barcode library for Ghana’s key commercial fish species.