Studies on the reproductive biology, condition factor, mortality, recruitment pattern and yield-per-recruit to the fishery of the West African fiddler crab Uca tangeri in Mbo river, Akwa Ibom State, Nigeria, was conducted for 12 consecutive months (April, 2012 - March, 2013). Values of all physico-chemical parameters were taken in-situ, using standard scientific equipments. Length-frequency data was analyzed using FISAT software. From the results, Uca tangeri a brackish water crab can thrive in Mbo river(a freshwater system), and that it was not a highly fished species, hence under-exploited. There is room for further utilization of the species.