Spatial Ecology and Habitat Connectivity of West African Manatee (Trichechus senegalensis) in the Niger Delta Riverine System

The West African manatee (Trichechus senegalensis) is a critically data-deficient species whose spatial ecology and habitat connectivity in the Niger Delta remain almost entirely undocumented, hindering effective conservation planning. This study investigated the spatial ecology, seasonal movement patterns, and habitat connectivity of manatees in the Niger Delta riverine network across Rivers and Delta States. Aerial transect surveys and acoustic detection using passive hydrophones were used to establish distribution and relative abundance at 32 survey sites over 18 months. Satellite telemetry data from three individuals tagged with archival GPS/Argos transmitters provided detailed movement trajectories and home range estimates. Habitat suitability modelling using maximum entropy analysis identified key habitat variables including water depth, aquatic vegetation density, freshwater access, and distance from human settlements. Manatees demonstrated highly individualised seasonal movement patterns, with wet-season home ranges averaging 47 square kilometres and dry-season ranges contracting to 12 square kilometres. Connectivity analysis revealed three isolated population clusters separated by oil infrastructure, fishing weir networks, and heavily modified river sections. Habitat suitability was highest in backwater creeks with dense aquatic vegetation and low boat traffic, which corresponded to the least surveyed areas. The study identified 18 kilometres of critical river corridor requiring conservation priority to maintain population connectivity. Entanglement in fishing nets was confirmed as the leading human-caused mortality driver through necropsies of three stranded animals. The study provides the first movement ecology data for this species in Nigeria. Keywords: West African manatee, spatial ecology, habitat connectivity, Niger Delta, telemetry.