Aspects of the ecology of Nigeria Fresh Waters: A case study on Physicochemical characteristics Plankton and Finfish from Lower Sombreiro River in Niger Delt

This paper is aimed at baseline information on the fisheries status of the fresh water reaches of somberiro river in the Niger Delta; while highlighting the challenges of obtaining fisheries data in the waters of the Niger Delta. Both physico-chemical and plankton were analyzed using standard methods Plankton and fish species were identified using monographs, descriptions, checklists and keys. The mean values temperature, pH, conductivity, turbidity, salinity, dissolved oxygen, total dissolved solids, dept, flow rate and rainfall were: 27.1 ± 0.09 (°C), 6.50 ±0.05, 4515.3±656.67 (μscm^-1), 1.8±.09 (ntu), 3.1±0.45(0/00), 7.10±0.06 (mg/l), 673.27±97.34(mg/l), 6.23±0.22(m), 0.19±0.39(m/s) and 184.1±19.89(mm) respectively. A total of 43 species from 5 taxonomic groups were recorded). The species with the highest number was Melosira granulata (357) with 5.2%, while the least number was for Stephanodiscus asroea (47) with 0.7%. Bacillariophyceae was the highest (50.3%), Chlorophyceae, 24.8%; Cyanophyceae, 15.4%; Xantophyceae, 7.2%; and Chrysophyceae, 2.5%. A total of 17 zooplankton species from 6 taxonomic groups were present. The species with the highest number (248) was Paracyclops fimbriatus, with 12.1%, while Mysis sp. had the lowest number (25) with 1.2%. The family Copepoda had the highest (45.5%), Cladocera, 23.4%; Euphaucea, 10.3%; Protozoa, 11.9%; Rotifera, 7.8%; and Decapod Crustaceae, 1.2% (the least). The family Copepoda had the highest (45.5%), Cladocera, 23.4%; Euphaucea, 10.3%; Protozoa, 11.9%; Rotifera, 7.8%; and Decapod Crustaceae, 1.2% (the least). A total of 72 finfish species from 38 families were present. Brienomyrus branchystius was the species with the highest number (412) accounting for 5.9% of total fish caught. No particular specie was dominant, Breinomyrus branchystius and B. longianalis were aboundant, Erpeptiochthys calabaricus and Chromidotilapia guentherieiro River in the Niger Delta, correlates the relationship between the biotic and abiotic parameters for the management of similar water bodies for regional, national and international fisheries development.