Brehan Mohammed*, Dereje Tewabe, Wonde Zelalem and Adane Melaku
Amhara Region Agricultural Research Institute, Bahir-Dar Fisheries and Other Aquatic Life Research Center, Ethiopia
Received: 18 February, 2016; Accepted: 01 April, 2016; Published: 04 April, 2016
Brehan Mohammed, Amhara Region Agricultural Research Institute, Bahir-Dar Fisheries and Other Aquatic Life Research Center P.O.Box 794, Bahir-Dar, Ethiopia, Tel: +251918389898; E-mail:
Mohammed B, Tewabe D, Zelalem W, Melaku A (2016) Physical, Chemical, Biological properties and fish species type of Geray reservoir, -W/Gojjam Zone, Ethiopia. Int J Aquac Fish Sci 2(1): 008-011. DOI: 10.17352/2455-8400.000012
© 2016 Mohammed B, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Physical; Biological and chemical parameters; Fish species type
The aim of the present study was to determine the physical, chemical and biological characteristics and to characterize the fishery of Geray reservoir. Three sites from the inlet site, the open water and the outlet has been selected and samples were collected using YSI 556MPS model multimeter and Palin test photometer 5000 .Temperature, pH, dissolved oxygen, salinity, Total Dissolved Solid, conductivity, secchi disk measurement, alkalinity, nitrate, phosphate, ammonia and turbidity were the parameters measured. Plankton sample collected using 55 and 80 micrometer mesh net. The most abund taxon was copepoda (666 ind. /m3 of water with their juvenile stages “Nauplia” or contributed 85% of total zooplankton taxa), which was followed by Cladocera (190 inds. /m3 or 15%). Among the 3 study sites the open water site showed higher density of zooplankton, especially cyclopod followed by outlet site. The inlet site was relatively low in zooplankton density. Cyprinus carpio, Varicorhinus Beso, Carasius Auratus and Oreochromis niloticus were species found in the reservoir. Almost all the physical and chemical parameters sampled of this reservoir water were within desirable limits for aquatic biodiversity the current state of the water quality of the reservoir is conducive for fish production. But the current management is not good for its sustainability, knowingly or unknowingly the activities done on and around the reservoir will shorten the sustainable utilization of the reservoir. The community should be awaked while they are starting to overexploit the resource.
Physico-chemical parameters of water play a significant role in the biology and physiology of fish . Water quality is determined by the physical and chemical limnology of a reservoir  and includes all physical, chemical and biological factors of water that influence the beneficial use of the water. Water quality is important in drinking water supply, irrigation, fish production, recreation and other purposes to which the water must have been impounded.
Water quality deterioration in reservoirs usually comes from excessive nutrient inputs, eutrophication, acidification, heavy metal contamination, organic pollution and obnoxious fishing practices. The use of the physico-chemical properties of water to assess water quality gives a good impression of the status, productivity and sustainability of such water body . The changes in physical characteristics like temperature, transparency and chemical elements of water such as dissolved oxygen, chemical oxygen demand, nitrate and phosphate provide valuable information on the quality of the water, the source of the variations and their impacts on the functions and biodiversity of a reservoir. Reservoirs are usually found in areas of water scarcity or excess, or where there are agricultural or technological reasons to have controlled water resources .
Treservoir has been studied. The results are expected to be a base line information for monitoring and tracking changes in the water quality as a result of the impact of human activities on the reservoir. Therefore the main aim of this study were to determine the physical, chemical and biological parameters of Geray reservoir and to identify the fish species in the reservoir.
Materials and Methods
Geray is located in Amhara Regional state Ethiopia, West Gojjam Administrative Zone, Jabitehnan and Finoteselam district, bordering, Shembekuma-Yedafas and Arebayitu-Insesa Kebeles. Three sites one from the inlet site, one from the open water and the other from the outlet was selected. In situ measurements in the morning at 4 o'clock samples of temperature, pH, dissolved oxygen, salinity, Total Dissolved Solid, conductivity were done using YSI 556 multiprobe meter. Secchi measurement was done using secchi disk.
Palin test photometer 5000 was used for analysis of total hardness, alkalinity, nitrate, phosphate and ammonia test. Fish samples collected using 6, 8, 10 and 12 cm stretched size mesh gillnet by setting the net overnight. Descriptive statistics has been used to calculate the mean and standard deviation values of the parameters. Data has been analyzed using simple Excel sheet 2010 and SPSS V.20 (Figures 1-3).