Scientific fishing programmes were carried out between 1979 and 2013 in several West African estuarine, coastal and lagoon ecosystems. Batrachoides liberiensis represented only 5.2% of the occurrences, of which the majority were recorded in the Sine Saloum estuary. This originality makes it possible to use this population to characterise certain features of the biology and ecology of this little described species. B. liberiensis was recorded in waters with a salinity of 25–46, transparency of 1–3.5 m, at depths of 2–10 m. It was particularly abundant in areas at a distance of 15–35 km from the mouth. The water temperature did not appear to be a determining factor for this species. The sex ratio of the population, whose total length ranged from 10 to 371 mm, was in favour of females (87%) with an estimated size at first maturity of 189 mm (total length). The parameters of the length-weight relationship were estimated at K = 1.0009*10−5 and b = 3.097. The diet of B. liberiensis consisted mainly of molluscs and crabs, present in respectively, 53.6% and 50.7% of the stomach contents analysed.