Genetic structure and demographic history of Anguilla bicolor from Tanzania based on mitochondrial cytochrome oxidase I sequence: Implications for effective management and conservation strategies

Abstract

Abstract A genetic analysis was conducted on Anguilla bicolor from Tanzania using the mitochondrial COI region. The study aimed to understand the population genetic structure and demographic history of A. bicolor. In this study, 42 samples of A. bicolor were collected from the Lower Rufiji River Basin and Pangani River in Tanzania between January and June 2023. The mtDNA COI sequences of 65 A. bicolor from various Indo‐Pacific countries were retrieved from GenBank. 2. The findings revealed an overall high haplotype diversity (0.83 ± 0.033) and moderate nucleotide diversity (0.63% ± 0.000). A limited genetic differentiation between populations was observed (FST = −0.00322, p = 0.0494), indicating gene flow, leading to an absence of population structure. The haplotype network tree also supported a panmictic stock in the Indo‐Pacific region with 44 haplotypes clustered around three principal haplotypes. Furthermore, the significantly overall negative values of both Tajima's D (−2.27, p = 0.002) and Fu's Fs (−26.36, p = 0.000) and the multimodal mismatch distribution suggested the presence of multiple demographic events in A. bicolor populations. Given the lack of substantial genetic structure among populations, managing the fishery as a single‐stock unit is advised, aligning with the current fisheries management practices in Tanzania. It is also crucial to ensure habitat quality along migratory paths to facilitate genetic exchange and long‐term species viability.