~ 45 ~ International Journal of Fisheries and Aquatic Studies 2016; 4(3): 45-51 ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.352 IJFAS 2016; 4(3): 45-51 © 2016 IJFAS www.fisheriesjournal.com Received: 06-03-2016 Accepted: 07-04-2016 Owato Gilbert Omondi Kenya marine and Fisheries Research Institute P.O Box 81651, Mombasa Olendi Robert University of Eldoret P.O.Box 1125 Eldoret Steve Omari Ngodhe Rongo University College P.O Box 103-40404-Rongo Correspondence Owato Gilbert Omondi Kenya marine and Fisheries Research Institute P.O Box 81651, Mombasa Assessment of Primary productivity, Nutrient levels and Trophic status of Kuinet dam, Kenya Owato Gilbert Omondi, Olendi Robert, Steve Omari Ngodhe Abstract This study was carried out in Kuinet (Chepkongi) Dam within Uasin-Gishu County, Kenya to assess primary productivity, nutrient levels and trophic status of the dam. Water samples were collected at four sampling stations (inflow, outflow and in the middle) of the dam monthly from November 2014 to January 2015. The samples were used to assess the chloropyhll-a, net primary productivity and the main physico-chemical variables. Phytoplankton was sampled using a phytoplankton net, identified and counted using an inverted electronic microscope. Canonical Correspondences Analyses was carried on to ascertain the correspondence relationships of the sampled parameters. The trophic status was calculated using the Carlson method considering the parameters: chloropyhll-a, Secchi Depth and Total Phosphorus. The phytoplankton community of Kuinet Dam is composed mainly of four families; Bacillariophyceae and Chlorophyceae families each had 11 species followed by Cyanophyceae with 5 species and Desmidiaceae with 3 species. The family Chlorophyceae dominated in abundance in all months. Net primary productivity ranged from 0.182±0.09 mgO2L -1 d - 1 in December to 0.299±0.13 mgO2L -1 d -1 in November. Dissolved Oxygen, net primary productivity, Biological Oxygen Demand and temperature displayed similar trends during the three sampling months. Chlorophyceae had near correspondence with these three parameters than the others according to CCA. The trophic status of the Dam resulted both mesotrophic and eutrophic. From the study, we reject the HO hence the primary productivity of Kuinet dam favors aquaculture during the dry spell period. This in turn aids in facilitating the achievement of attaining the estimated potential production level of 2000 tons according the Uasin Gishu district environment action plan 2009-2013. Keywords: Assessment, Primary productivity, Nutrient level, Trophic status, Kuinet dam 1. Introduction Primary productivity is a desirable attribute for environmental health of surface waters (dams, rivers, lakes, estuaries and oceans) [13] . The critical importance of ensuring an optimum environmental quality of any aquatic environment is a major factor in obtaining good productivity and ultimately high fish yields (Ryder, et al. 1982.) The quality of surface waters in this environment is determined by the chemical, physical and biological characteristics but owing to inadequate management of wastes, freshwater for production potential has been reduced due to widespread pollution. Previous studies have shown deterioration of water quality and low faunal abundance and diversity caused by stress imposed by effluents from land based sources [11] . This, therefore, calls for continuous investigation into the processes that occur in our water systems. There is need to know the trophic status of dams/reservoirs ecosystems in order to know the aquaculture potential, which have not yet been exploited much for aquaculture production despite their potential, since this information is not available despite their potential [13] . Among the 3,000 minor reservoirs (<0.1km 2 ) in Kenya that have been constructed to supply water for industrial and domestic use, irrigation farming and watering livestock and wildlife (Balarin, 1985), many reservoirs have been stocked with fish, with the aim of increasing their productivity and support local livelihoods. Before the year 2030, the Kenyan government has plans to add around 2,000 dams in arid areas [20] . Among the constructed dams to supply farmers with water for irrigation [25] , some have been stocked with fish, however, their suitability and potential for aquaculture is not yet established. In Uasin Gishu country there are over 120 dams with an average annual production of 3000kg of fish and the fisheries production patterns in these environment has been increasing drastically and has an estimated potential production level of 2000tons, this has a drawback