Unveiling interconnectedness between marine protected and non-protected areas in Tanzania: Insights from barred mudskipper (Periophthalmus argentilineatus) population genetic structure

Marine protected areas (MPAs) are globally recognised for their role in safeguarding marine fisheries from the detrimental impacts of human activities and climate change. Tanzania, in alignment with global conservation efforts, has designated 18 MPAs and plans to establish four more in the Southwestern Indian Ocean. However, a critical challenge arises from the lack of a thorough understanding of genetic connectivity between populations in MPAs and non-protected areas (NPAs). To address this, 151 mitochondrial D-loop sequences (357 base pairs) of Barred mudskipper (Periophthalmus argentilineatus) were analysed to assess genetic connectivity between MPAs and NPAs in Tanzania. The findings revealed a low and insignificant index of genetic differentiation (F-ST = -0.0046, p > 0.05) between populations in MPAs and NPAs. Furthermore, haplotypes from both MPAs and NPAs did not cluster based on their geographical origins, with over 9 haplotypes shared between these areas. Additionally, the measured haplotype and nucleotide diversities did not differ significantly between MPAs and NPAs (p > 0.05). However, MPAs showed a significantly higher number of private haplotypes compared to NPAs (p < 0.05). These findings suggest high genetic interconnectedness between populations in MPAs and NPAs, underlining the importance of existing MPAs in preserving local genetic diversity and their potential to replenish depleted NPAs. However, realising the full potential of this interconnectedness necessitates stringent enforcement of sustainable fishing practices to alleviate pressure on fish stocks. It also requires the protection of critical habitats that serve as corridors for fish dispersal, facilitating interconnectedness between MPAs and NPAs.