Published Article

ABSTRACT

Freshwater ecosystems support a disproportionately high share of global biodiversity despite occupying only a small fraction of the Earth's surface. Nigeria possesses extensive freshwater resources, including the Niger and Benue river systems, Lake Chad, floodplains, wetlands, reservoirs, and numerous streams that sustain a diverse assemblage of fish species. These ecosystems provide critical ecological functions and support food security, livelihoods, and cultural values for millions of people. However, freshwater fish biodiversity in Nigeria is increasingly threatened by habitat degradation, pollution, overexploitation, invasive species, hydrological alterations, and climate change. This review synthesises current knowledge on the diversity, distribution, ecological significance, and conservation status of freshwater fish species in Nigeria. Available evidence indicates that Nigerian inland waters harbour more than 260 freshwater fish species distributed across several taxonomic groups, with families such as Cichlidae, Clariidae, Mormyridae, Mochokidae, and Claroteidae being particularly prominent. Despite this richness, many species are experiencing population declines, while others are categorised as threatened, endangered, or near-threatened due to increasing anthropogenic pressures. The review further examines the ecological and socioeconomic consequences of biodiversity loss, including disruptions to ecosystem functioning, reduced fisheries productivity, and threats to rural livelihoods and food security. Existing conservation measures are assessed, and key knowledge gaps limiting effective biodiversity management are identified. The study highlights the need for integrated conservation strategies that combine habitat protection, sustainable fisheries management, community participation, policy reforms, and emerging monitoring technologies. Strengthening biodiversity assessment and conservation efforts is essential for safeguarding Nigeria's freshwater fish resources and ensuring the long-term sustainability of inland aquatic ecosystems.