Asian Journal of Fisheries and Aquatic Research

Synodontis nigrita is a special food fish and delicacy cherished by many people in the riverine communities of Nigeria. There is a need to identify the parasites of S. nigrita and the anthropogenic and environmental drivers of parasitism and physiochemical fluxes. Three interconnected rivers in Uruan Local Government Area, Akwa Ibom State, Nigeria, designated as Ibikpe River (Station 1), with Lat: 5^o6’38.34” N and Lon; 8^o0’50.616” E; Mbiakong River (Station 2), with Lat: 5^o4’16.932” N and Lon: 8^o1’50.699” E; and Nwaniba River (Station 3), with Lat: 5^o2’52.188” N and Lon: 8^o247.689” E, were selected for this study. Sampling was conducted from September to December 2025. A total of 108 S. nigrita of different sizes were caught, with 27 fish sampled per month. The fish were examined for the presence of ecto- and endoparasites. River water was analysed for 16 physiochemical parameters. Parasite prevalence and abundance, together with the effects of anthropogenic activities on physiochemical parameter fluxes, were analysed. Synodontis nigrita caught at Station 1, Ibikpe River, was heavily parasitised by the flagellated protozoan Ichthyobodo pyremia, with a prevalence of 100%, and the nematode Capillaria zederi, with a prevalence of 77.78%. The pathogenic flagellated protozoan Cryptobia iubilans and the coccidian protozoan Goussia carpellia were also harboured by the fish at low prevalence rates of 11.11%. At Station 2, Mbiakong River, S. nigrita was parasitised by Camallanus spp., with a prevalence of 55.56%, and Procamallanus spp., with a prevalence of 1.02%. At Station 3, Nwaniba River, S. nigrita was predominantly parasitised by Procamallanus spp., with a prevalence of 66.67%. The fish also harboured Camallanus spp. at 44.44%, the crustacean ectoparasite Argulus foliaceus at 33.33%, and Capillaria zederi at 1.02%. Phosphate and sulphate contents were consistently higher at Station 3, Nwaniba River, than at the other rivers. Parasite abundance in Nwaniba was significantly higher than in the other rivers (P<0.05), P=0.07. Parasite abundance in Ibikpe River was next highest, with a value of 4.30±0.07. Mbiakong River had the lowest protozoan abundance. Nitrite, nitrate, ammonia, dissolved oxygen, pH, salinity, and the other physiochemical parameters increased from September to December, suggesting seasonal effects. Anthropogenic activities such as hotels, timber sawmills, and markets were associated with increased physiochemical parameters, increased nematode infections, and reduced protozoan, cestode, and crustacean infections.