Thesis and Dissertations

STUDY ON PARASITIC PATHOGENS OF COMMERCIALLY IMPORTANT FISHES IN EASTERN, WESTERN AND SOUTHERN PARTS OF LAKE TANA, ETHIOPIA

Wed, 23 Feb 2022 00:00:00 GMT

STUDY ON PARASITIC PATHOGENS OF COMMERCIALLY IMPORTANT FISHES IN EASTERN, WESTERN AND SOUTHERN PARTS OF LAKE TANA, ETHIOPIA Solomon Orion A crosssectional study on parasitic infections of fish was conducted from December 2011 to May 2012 at Lake Tana to identify parasites of important fish species. The fish were sampled from three different sites (South, East and West) of the lake and the sampling were taken at morning time randomly on different boats and transported to the recommended laboratory by cooler jar filled with water from the lake itself From the total of 1197 samples 924 (77.2%) were infected, Labeobarbus species (n = 450, 52. 13%), Nile tilapia (Oreochromis niloticus) (n = 477, 78.53%) and catfish (Clarias gariepinus) (n = 300, 18.63%) were examined using standard laboratory techniques. From total number of fishs examined 450 (43.9%) were males and 7 47 (71. 8%) females. Accordingly, the major parasite noticed during investigation include the dominant encysted pleurocercoid with prevalence rate of (28.9%) followed by the monogenean Clinostomum species (18.3%) and Contracaecum species larvae (17.8%). From all organs examined, skin was highly infested by eight different types of parasites (11. 75) and external crustacean, Dolops species (5.26%). The external protozoa (Trichodina species) ( 4. 5%) was found only in southern part of the Lake. Fish from the three areas were infested with different parasite species and the southern partof the lake was found to harbour the highest prevalence (150.4%) of parasitic infestations. The larval nematode Contracaecum species had highest mean intensity of 3 in the South, 4 in West and 5 in East and with mean abundance of 0.15, 0.63 and 0.58, respectively. Further assessment of parasites in thier intermediate and final hosts like piscivorous birds as well as in humans is paramount important.

Fish Market Chain Analysis and Livelihood of Local Fishers: the case of Southern Gulf of Lake Tana, A thesis submitted to Graduate Program in Partial Fulfillment of the Requirements for the Degree of Master of Science in Fisheries and Wetlands Management Ethiopia

Wed, 23 Feb 2022 00:00:00 GMT

Fish Market Chain Analysis and Livelihood of Local Fishers: the case of Southern Gulf of Lake Tana, A thesis submitted to Graduate Program in Partial Fulfillment of the Requirements for the Degree of Master of Science in Fisheries and Wetlands Management Ethiopia Kidanie Misganaw This study examined the fish marketing chain and livelihood of local fishers at Lake Tana. The southern Gulf of Lake Tana has three major landing sites (Saint Michael, Saint George and Robit Bata). The study areas were selected purposively as the fish market outlet of Lake Tana is confined to the southern part of the Lake near Bahir Dar city. Primary data were generated from 90 fishers respondents selected randomly from the three landing sites. In addition, market related data were collected from 5 assemblers, 6 retailers, 2 wholesalers, 30 consumers and 19 hotels. Both descriptive and econometric analyses were used to analyze the data. From sample motorized and reed boat owner fishers were 33.3% and 66. 7%, respectively. Fishing, crop production, animal husbandry, petty trade and causal laborer contributed 66%, 21 %, 6%, 2% and 5% of fisher's livelihood, respectively. The study revealed that 87. 5% of the total fish production was supplied to the market. The highest average proportion of fish production supplied to the market was observed in Saint Michael (3 9. 4%) and Saint George (3 7. 8%) and the lowest in Robit Bata (22.8%). The Ordinary Least Squares (OLS) estimation shows that distance fishing ground, educational level, casual labor, credit supply, fishing trip and gillnet number are the significant determinants of the market fish. The Structure Conduct Performance (SCP) identified that the markets for fish in the study area was non-competitive type. The highest (955. 9 ETB/Qt) and the lowest (311.96 ETB/Qt) gross profit in fish marketing was obtained by retailers and fishermen, respectively. Generally, fish market in the study area seemed to be inefficient and underdeveloped. Fishers, assemblers, retailers, Fish Production and Marketing Enterprise, cooperatives, wholesalers, hotels and consumers were found to be important fish market intermediaries of the Lake Tana fishery. Fisheries development interventions should be aimed at addressing both fish production and marketing problems. The study further suggested that fish quality, fish supply, education and training, license of fishing activity and improving access to services should receive due attention in order to improve fish marketing and production in the region.

Assessment of Motorized Commercial Gillnet Fishery of the Three Commercially Important Fishes in Lake Tana, Ethiopia

Wed, 23 Feb 2022 00:00:00 GMT

Assessment of Motorized Commercial Gillnet Fishery of the Three Commercially Important Fishes in Lake Tana, Ethiopia Brehan Mohammed This study was conducted from July 2010 to June 2011 to assess the status of motorized commercial gillnet fishery of the three commercially important fishes in Lake Tana and to compare it with the previous findings. Total weight of three taxa (Labeobarbus spp., Oreochromis niloticus, Clarias gariepinus) caught by the motorized boats of the commercial fishery in Lake Tana were taken every day and additional data on number of gillnets used, mesh size, location of fishing grounds and unsold fish, being discarded or used for own consumption were collected. Data on the Labeobarbus species composition of the commercial gillnet fishery with maximum of 200 specimens were collected every month in the first three consecutive days for a year. The total fish yield from the main fishing grounds of the commercial fishery was 238 metric tons/year. In the present study, the catch of tilapia ( 0. niloticus) in Lake was by far higher than that of Labeobarbus and catfish (C. gariepinus) with a proportion of 71 %, 11 % and 18%, respectively. Peak production season lied between March and May 2011. The total number of gillnets set and boat trips made were 85,943 and 3104, respectively which is by far higher than the previous studies of Lake Tana commercial fishery. The Catch per Unit effort (CpUE; kg/trip) of the 2010/2011 production year was 64.7 ± 3 at 95% CI. The vast majority of the fishing effort (80% of the effort) was allocated to the North Eastern Floodplain (NEFP). Labeobarbus CpUE was found to be 6.11 kg/trip in 2010/2011, which is by far lower than the previous reports. Clarias garipienus CpUE was 7.8 kg/trip, which showed a decreasing tendency from the previous studies. The same was for 0. niloticus CpUE which was 42.21 kg/trip. An integrated management plan and research program for the Lake Tana basin is urgently required to prevent the collapse of an important fishery and the extinction of the only known cyprinid species flock in the world.

Assessment of the Macroinvertebrate Community of the Enfranz Stream, Southern Lake Tana, Ethiopia

Wed, 23 Feb 2022 00:00:00 GMT

Assessment of the Macroinvertebrate Community of the Enfranz Stream, Southern Lake Tana, Ethiopia Abrehet Kahsay The assessment of macroinvertebrate community of the Enfranz stream, located northwest of Bahir Dar city in the southern part of Lake Tana, was studied in wet and dry seasons from August 2010 to May 2011. This stream feeds Lake Tana and its total catchment area is 198 krrr'. Four sampling sites were selected along the stream. Physicochemical parameters, temperature, dissolved oxygen, conductivity and pH, were measured. Macroinvertebrates were collected using standard dip net based on the Rapid Bio Assessment Protocols for use in streams and . wadeable rivers. Most physicochemical parameters varied significantly (P < 0.05) among sampling sites. A total of 15286 macroinvertebrate individuals, belonging to 30 families were identified. Macroinvertebrate metrics for stream water quality assessment were calculated: total Taxon Richness (TR), % Dominant Taxa (DT), Shannon Wiener diversity index (ff), Pielou Evenness Index (J'), Percent Ephemeroptera (%Eph), Percent Trichoptera (%Tri ch), Hilsenhoff Family-Level Biotic Index (HFBI) and Percent Dipterans (%Dip). Results of ANOVA showed that macroinvertebrate metrics differed significantly among sampling sites and seasons (P < 0.05). Pearson's correlation coefficients showed that, physicochemical parameters were significantly correlated with macroinvertebrate metrics. It was found that human activities such as agriculture and grazing changed the bank of stream by reducing the overall water quality and macroinvertebrates, it is recommended to create forested buffer zone that promotes the broader diversity of habitats and protect the stream from point-source and non-point-source pollution. Efforts to assess and monitor biological conditions in this stream should include habitat quality assessment and comprehensive analysis of water quality parameters.