http://ir.bdu.edu.et/handle/123456789/1712 2001-01-13T06:42:17Z http://ir.bdu.edu.et/handle/123456789/10105 SPECIES COMPOSITION, DIVERSITY AND RELATIVE ABUNDANCE OF BIRDS IN LAKE ZENGENA AREA, AWI ZONE, ETHIOPIA Yonas, Ayele Birds are an excellent indicators of biodiversity productivity. They are vigorous for ecological functions such as indicators of pollution, seed dispersal, scavenging offal and a predators of an insects. The present study was carried out during both dry and wet seasons, from August 2018 to January 2019, with the objective to assess species composition, diversity and relative abundance of birds in the Lake Zengena Area, Awi Zone, Ethiopia. Data were collected using line transect, point count and direct observation methods for five consecutive days. A total of 100 birds species belonging to 43 Families and 12 Orders were recorded. The order Passeriformes was the dominant order represented with 57 species and 24 families. The family Accipitridae and Muscicapidae were the dominant families symbolized by nine species each. Two bird species were endemic to Ethiopia. These are Spot-breasted plover (Vanellus melanocephalus) and Blue-winged Goose (Cyanochen cyanoptera). However, the nine bird species were found endemic to both Ethiopia and Eritrea. The Great-breasted Cormorant, Blue-winged Goose, Hooded Vulture and Ruppell′sVulture were Endangered, Vulnerable, Critically Endangered and Near Threatened respeclively. The Wattled ibis (Bostrychia carunculata) was the most abundant species followed by Hadada ibis (Bostrychia hagedash) and Red-cheeked Cordon-bleu (Uraeginthus bengalus) with high sighting records. The six species were the least abundant with one sighting records. Diversity and evenness indices during the wet and dry seasons were 3.52, and 0.82; and 3.47 and 0.83, respectively. The highest species diversity (H’=3.4), species evenness (E=0.82) and species richness (RI=8.88) were observed in the lake area with the natural forest. The lowest species diversity (H’=3.09) and species richness (RI=7.13) were recorded in the habitat of plantation, but the species evenness (E=0.78) was lowest in grassland habitat. Bird species diversity, distribution and abundance depend on habitat homogeneity and heterogeneity. Heterogeneous habitat support various species of bird than the homogeneous habitat. In natural forest habitat recorded high species diversity might be due to high vegetation cover and minimum human disturbance. The homogeneity of habitat contribute low species diversity in the plantation habitat. Livestock grazing, firewood collection, tourists recreational activities and building are the main threats for distribution of birds in the present study area. Therefore, conservation action is needed to minimize these threats. Keywords: Birds, Lake Zengena, Species composition, Species diversity, Species evenness, Species richness 2019-12-26T00:00:00Z http://ir.bdu.edu.et/handle/123456789/10081 AGE, GROWTH AND STATUS OF NILE TILAPIA (OREOCHROMIS NILOTICUS) STOCK IN LAKE TANA, ETHIOPIA Degsera, Aemro This study has been conducted in Lake Tana Nile tilapia, Oreochromis niloticus, fishery. The length and weight of individual O. niloticus from fishery-independent data and catch as well as effort data of fishers have been used to analyses O. niloticus fishery for 2016/2017 production year. The aim of the study was to examine the extent of immature O. niloticus exploitation in the Bahir Dar Gulf of Lake Tana area, to estimate age, growth, maximum sustainable yield (MSY) and effort at maximum sustainable yield (fMSY) for the whole lake. Fish samples were collected monthly from April 2016 to March 2017 using gillnets of different mesh sizes. Samples collected during the breeding time were used to determine the length at first maturity of fish (L50%). A logistic function was fitted to estimate L50%. Catch and effort data were collected from three sites starting June 2016 to May 2017 from Reed boat and motorized boat fisheries. Catch and effort data were also collected from the chase and trap fishery from May to July 2016. The percent of catch below L50% was calculated from the two types of fisheries. The difference in the distribution of the catch per unit effort (CpUE) of O. niloticus among study sites and seasons was tested using two-way ANOVA. Otolith samples collected from June 2016 to May 2017 were placed at 97% of ethanol for three days and they were transferred into 45% glycerol for 7 days. Sagittal otolith was ground using Carborundum papers for microscopic examination. The age of the fish was determined from the total number of translucent macrozones counted in the otoliths based on knowledge of the time of translucent zone formation and breeding season of the fish. The precision of estimated age was done by average percent error (APE) and coefficient of variation (CV). The periodicity of annuli formation was validated using marginal increment analysis (MIA) and edge analysis (EA). The von Bertalanffy Growth Function (VBGF) parameters for observed and back-calculated length at age function were estimated following a non-linear curve fitting procedure. For MSY and fMSY estimation, catch and effort data were collected from four landing sites. Linearized lengthbased catch curve analysis was employed to estimate the total mortality coefficient (Z) and natural mortality was estimated with Pauly’s empirical formula. Fishing mortality (F) was calculated as Z-M. The Jones length-based cohort analysis was used to estimate the population abundance and F coefficient by length group. The outputs of length-based cohort analysis were used as input data for the Thompson and Bell yield prediction model to predict sustainable fish yield at different levels of F-array. The L50% for males (20.5 cm) was relatively higher than xv females (19.6 cm). The overall mean CpUE for O. niloticus in Lake Tana was 23.8 kg per trip. The CpUE was significantly different among the study seasons (P = 0.000) and sites (P = 0.002). Of the total catch at Bahir Gulf, about 24% of the motorized boat and reed boat fisheries and 46% of the chase and trap fishery were below L50%. Totally 1,596 samples were collected for age and growth works. The highest percentage of the translucent zone was recorded in June, July, January and February; whereas the lowest was observed in October, November, March, April, and May. The mean relative marginal increment was highest in November, December and May; and the lowest was observed in June, July, J 2019-12-24T00:00:00Z http://ir.bdu.edu.et/handle/123456789/9797 FOOD AND FEEDING HABITS OF LARGE CYPRINID FISHES IN UPPER BLUE NILE RIVER, ETHIOPIA Marishet, Teshome Food and feeding habits of large cyprinid fishes (Labeobarbus intermedius, Labeobarbus nedgia and Labeo forskalii) were studied from November 2016 to March 2017 in upper Blue Nile River, Ethiopia. Four sampling sites were selected and fish specimens were sampled during the post-rainy season (November 2016) and dry season (March 2017) using multiflaments of (6, 8, 10, 12, 14 cm) and monofilaments (6, 8, 10 cm) mesh sizes. The length-weight measurements of each specimen were taken onsite. A total number of 401 cyprinid fishes were collected from all sampling sites. One hundred twenty two (30.4%) of the collected cyprinid specimens were recorded with empty guts and 279 (69.6%) of them were with non-empty guts. The whole contents of all non-empty gut specimens from all sampling sites were taken, labelled and preserved using 5% formaldehyde solution for further analysis. In laboratory, all the collected gut contents were examined and identified to different food items using compound and stereo microscopes. The relative importance of each identified different food items in the diet compositions were analyzed using frequency of occureence and volumetric analysis. The length-weight relationship of cyprinid fishes in Blue Nile River showed statistically significant curvilinear relationships. The diets of cyprinid fishes (L. intermedius, L. nedgia and L. forskalii) were composed of a variety of food items including phytoplankton, mud, insects, detritus, macrophytes, sand grains, nematodes, fish scales, zooplankton and gastropods. Specifically, phytoplankton, insects and detritus were the large food categories in the diet of L. intermedius by occurring in 99.3%, 76.6% and 87.2% of stomachs, respectively and accounted for bulk (87.5%) of total food by volume. Whereas, L. nedgia mainly fed on insects and phytoplankton which contributed 37.4% and 34.7% of total volume, respectively. Mud was frequently ingested by L. forskalii and it contributed 57.7% of total volume to the diet of this species. During the post-rainy season, insects and phytoplankton were mostly ingested food items by L. intermedius and L. nedgia while L. forskalii mainly fed up on mud in Blue Nile River. However, during the dry season, phytoplankton was the most important food items in the diet of all cyprinid fishes of the river. Based on results of the current study, L. intermedius and L. nedgia might be omnivores in their diet but L. forskalii seemed to be detrivorous. Keywords: Blue Nile River, Diet composition, Feeding habits, Large Cyprinid fishes 2019-10-04T00:00:00Z http://ir.bdu.edu.et/handle/123456789/9744 ASSESSMENT ON DIVERSITY, ABUNDANCE AND DISTRIBUTION OF MEDIUM AND LARGE SIZE MAMMALS IN GUNA MOUNTAINS COMMUNITY CONSERVATION AREA. COMMUNITY CONSERVATION AREA, SOUTH GONDAR, ETHIOPIA. Dereje, Chukala Guna Mountains Community Conservation Area is found in South Gondar. It was formally established as a community conservation area in 2016. The concern of this study is to estimate the diversity, abundance, and distribution of medium and large-size mammalian in different habitat types of Guna Mountains Community Conservation Area. The study area was divided into four habitats (Guassa grassland, Plantation, open grassland with scattered Lobelia and Helichrysum, and Erica moorland) based on vegetation type during a preliminary survey. Representatives sample sites were taken from each habitat types and surveyed using the line transect method. Overall 25 transect lines (8 transect lines on Guassa grassland, 5 transect lines on Plantation, 5 transect lines on Erica moorland, and 7 transect lines on Open grassland with scattered Lobelia and Helichrysum) were laid systematically in all habitats to study and collect data on mammalian species diversity, abundance, and distribution. The study was conducted from December 2018 to May 2019. Data collected from the study area was coded, entered and analyzed by using SPSS version 22 and Microsoft Excel. Species diversity was calculated by Shannon diversity index. Distribution of species among different habitat types was analyzed by chi square association test. A total of 13 medium and large-size mammalian species those belong to 8 families and 6 orders were recorded in the study area. The higher number of species were recorded in Plantation (5 species) followed by Guassa grassland, (4 species) whereas the lower number of specie was recorded in open grassland with scattered Lobelia and Helichrysum (2 species). Relative abundance of different species was statistically significantly different (χ2=1197.276, df=12, p = 0.001). The diversity index was higher in Plantation (0.94), whereas lower diversity index was recorded in open grassland with scattered Lobelia and Helichrysum (0.13). Results revealed that statistically significantly difference in mammalian distributions in different habitat types (χ2 =1167.33, df =36, p = 0.001). Rock hyrax (P. capensis) was the most abundant (42.2%) species followed by T. gelada (32.85%). Whereas Canis aureus was the least abundant (0.5%) species. Currently, the area was suffering from different human activities mostly from agriculture and settlement expansion and cattle grazing. Administrative units and all other concerned bodies shall cooperate to limit the impact of anthropogenic a 2019-09-23T00:00:00Z