Managing Invasive Species Impacts on Freshwater Ecosystems in the Lake Chad Basin, North East Nigeria

This study examines the professional management of invasive aquatic plant species and their impacts on freshwater ecosystems in the Nigerian portion of the Lake Chad Basin, focusing on the management responses to the spread of water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in rivers, irrigation channels, and remnant lake sections in Borno and Yobe States. Invasive aquatic plants have spread rapidly in the Nigerian Lake Chad Basin in recent years, forming dense mats that impede fishing, block irrigation canal intakes, reduce water quality by depleting dissolved oxygen, and eliminate native aquatic plant communities. The study assesses invasive species management programmes implemented by the Lake Chad Basin Commission, the Borno and Yobe State governments, and rural fishing communities, drawing on programme documentation, field observations at twelve affected water body sites, and interviews with 40 fishing community members, 10 irrigation scheme managers, and 8 Lake Chad Basin Commission officials. Results show that management responses are predominantly reactive physical removal operations that achieve temporary clearance but fail to prevent regrowth due to high reproductive rates and absence of biological control agent deployment. Preventive management including surveillance for new colonisation fronts is absent. Community awareness of the invasive nature of these species is low, with many fishers unaware that these are non-native plants. Recommendations include establishing a Lake Chad Basin invasive species early warning network and evaluating the biological control agent Neochetina weevils for deployment under appropriate biosafety assessments. Keywords: invasive species, water hyacinth, Lake Chad Basin, freshwater management, North East Nigeria.