Aquaculture and Fishery Management

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/92

Browse

Filter results by typing the first few letters
Now showing 1 - 12 of 12
  • No Thumbnail Available
    Item
    BACTERIAL PATHOGENS OF NILE TILAPIA FISH, Oreochromis niloticus (LINNAEUS, 1758) WITH SPECIAL REFERENCE TO Aeromonas hydrophila IN LAKE HAWASSA, ETHIOPIA AND MODULATION OF INFECTION USING DIEATERY SUPPLIMENTATION WITH GINGER (Zingiber Officinale)
    (HAWASSA UNIVERSITY, 2024-03) ALAZAR ERGENA KESHAMO
    Fish is one of the known aquatic animals which serve as food for human beings. However, fish are constantly exposed to diseases and usually succumb to infections after being exposed to stress. Environmental factors such as variations in the physico-chemical parameters of water act as stressors and can predispose fish to diseases. This study was thus undertaken to evaluate the physico-chemical and bacteriological quality of Lake Hawassa, characteriz bacterial pathogens with emphasis on Aeromonas hydrophila of Oreochromis niloticus, and asses the effect of Ginger (Zingiber officinale) powder on Aeromonas hydrophila infection. Seventy-two water samples and 360 fish samples were collected from Lake Hawassa for 12 months from January 2021 to December 2021. The physico-chemical and bacteriological quality of the water, isolation, characterization and identification of bacterial pathogens of fish and, haematological parameters of fish were assesed following standard procedures. To test the pathogenicity of Aeromonas hydrophila and their effects on haematology of fish, 270 fish were collected from the ponds located at Hawassa University and transported to the laboratory and fed a basal diet. After two weeks of acclimatization, the fish were divided into one control and eight treatments each in triplicaten and injected with different concentrations of Aeromonas hydrophila (1 x 101 to 1 x 108 CFU/ml). To determine the effect of Ginger powder on the haematology of Oreochromis niloticus and Aeromonas hydrophila infection 300 fish were collected from the Fish ponds located in Hawassa University and transported to laboratory and fed a basal diet during two weeks of acclimatization. The fish were distributed into one control and four treatment groups and fed with different concentrations of Ginger powder (0.00, 1, 3, 5, 8 and 12 g ginger/kg) for eight weeks. At the end of eight weeks, the fish were injected with 0.2ml of Aeromonas hydrophila at the concentration of 1 x 107 CFU/ml. Blood samples were collected from the fish before and after the Aeromonas hydrophila injection. The study showed a significant variation in water quality parameters xviii among sites and seasons (P < 0.05). Seventy-two point seven percent (72.7%) of physico- chemical parameters of Lake Hawassa were not found with in the critical limits for aquatic life, particularly fish. The study also indicated high bacterial loads in water samples of the lake. Sixty-four percent (64%) prevalence of bacterial infection was recorded for fish in the lake. The prevalence of infection in female fish was higher than in male fish. The highest prevalence was recorded within the smaller fish group (12-18 cm) than the larger ones (24-29 cm). Significantlly high bacterial loads were recorded from the intesitine of fish during the summer (wet) season (P < 0.05). Bacterial isolates such as Aeromonas hydrophila, Escherichia coli, Edwardissela tarda, Vibrio, Bacillus, Staphylococcus, Salmonella, Flavobacterium, Pseudomonas and Shigella species were isolated from Oreochromis niloticus of Lake Hawassa. A prevalence of 17.7% of Aeromonas hydrophila was recorded in Nile tilapia. All Aeromonas isolates were 100% resistance to amoxicillin, ampicillin and penicillin. The majority of Aeromonas isolates showed multiple antibiotic resistances. The value of red blood cells (RBCs), haemoglobin (Hb) and haematocrit (Hct) was significantly decreased (P < 0.05) in the blood of Oreochromis niloticus collected from more polluted sites of the lake compared to relatively less polluted site. In contrast, erytrocyte sedimentation rate (ESR) and white blood cells (WBCs) count showed significant (P < 0.05) elevation for more polluted sites than less polluted site. RBCs count, Hb, Hct and WBCs count showed a significant rising trend in their values with increasing size of the fish (P < 0.05). The male fish have significantly higher concentrations of haematological parameters, such as RBCs, Hb and Hct than the females (P < 0.01). Haematological parameters of infected fish were significantly different from control fish (P < 0.01). The haematological parameters of the fish such as RBC, Hct, Hb, MCH, MCHC and WBC were significantly increased to all concentrations of the Ginger powder-supplemented diet when compared to fish fed the control diet. There was no mortality of Oreochromis niloticus before injection xix with Aeromonas hydrophila. Mortality in experimental fish was observed after 3 days of the bacterial challenge. The highest mortality rate (70%) was recorded for the control group followed by the 3 g/kg and 12 g/kg Ginger powder-supplemented diet. Supplementation of Ginger powder at the concentration of 5 g/kg diet provided better protection to Oreochromis niloticus against Aeromonas hydrophila infection. There is an urgent need for continuous monitoring of Lake Hawassa to detect changes in the water quality. The recovery of potentially pathogenic bacteria of humans, in the fish, suggests that if the fish are improperly handled, undercooked, or consumed raw may cause diseases in susceptible consumers. The use of 5 g/kg dietary Ginger powder diet is recommended for the control of Aeromonas hydrophila infection in Nile tilapia, Oreochromis niloticus.
  • No Thumbnail Available
    Item
    EFFECT OF THIOUREA CONCENTRATION ON THE STRUCTURAL AND OPTICAL PROPERTIES OF PbS THIN FILMS SYNTHESIZED BY CHEMICAL BATH DEPOSITION METHOD
    (HAWASSA UNIVERSITY, 2024-11) ADDISU MINAYEHU ENGIDA
    In the present work lead sulfide (PbS) thin films were synthesized on glass substrate by chemical bath deposition method as material employing lead acetate as a source of Pb2+ and thiourea as a source of precursor S2- and sodium hydroxide as complexing agent in the solution of distilled water. The thin film have been deposited at constant bath temperature of 800c and the deposition time was 20 minute for different samples in the various 0.2M thiourea concentrations of 8, 9, 10, 11 and 12 mL respectively. The thin films were characterized by using X – ray diffraction and UV – Vis spectrophotometer. X-ray diffraction analyses revealed that all the films were polycrystalline in nature with the diffraction peaks indices to the face centred cubic structure. For as the deposited thin films, it revealed that PbS nanocrystalline with preferred orientation along the (111) for 8 mL which changes to (200) for 9 – 12 mL in per set of 1 mL for various thiourea concentration due to the change of the total system free energy during the film growth. The structural parameters, such as the lattice constant (a), crystallite size (D), dislocation density (ρ) and micro strain (ε) were evaluated from the XRD spectra. The average crystalline size was calculated using the Debye – Scherer’s formula and found to decrease from 35.71 to 29.64 nm with an increase thiourea concentration in the case of increasing the growth rate, at fast deposition rate and growing species has no enough time to be organized. The dislocation density and micro strain were found to vary inversely with the crystallite size, whereas the lattice constant was found to decrease with a decrease of in crystallite size. The UV – Vis spectroscopy characterization of the sample revealed that the optical band gap of energy was increased from 1.55 to 1.61 eV with increasing thiouera concentration due to the quantum size effect of polycrystalline PbS thin film. Keywords: Chemical bath deposition, Lead sulphide, thin films
  • No Thumbnail Available
    Item
    EFFECTS OF DIFFERENT PROCESSING METHODS ON NUTRIENT COMPOSITION OF SWEET POTATO LEAF AS FEED FOR NILE TILAPIA, OREOCHROMIS NILOTICUS (LINNAEUS, 1758)
    (HAWASSA UNIVERSITY, 2023-10) TIGIST SEYFE BELACHEW
    The use of alternative feeds aims to increase productivity and reduce the feed costs in aquaculture production. The present study was conducted to evaluate the effects of different processing methods on nutrient composition of sweet potato leaf (SPL) and its effect on growth performance, feed utilization and body composition of O. niloticus. Fresh sweet potato leaves were collected and processed differently, namely air dried (AD); yeast fermented (YF); rumen fluid fermented (RF) and naturally fermented (NF). Following proximate analysis five isonitrogenous and isoenergetic feed: one control diet and four processed SPL based diets were formulated by replacing 30% CP of SBC with processed sweet potato leaf CP. A total of 300 Nile tilapia fingerlings each with an average body weight of 10.55±0.19g were stocked in 15 hapas installed in the concrete ponds in triplicate and fed with 5% of their body weight three times a day for three months. The results of proximate analysis of SPL showed the highest CP (33.9%), and lowest CF (7.80%) in YF and the highest fat (8.55%) and ash (12.14%) content were recorded in RF. AD SPL showed the highest DM (93.41%) and NFE (55.87%) content. The fish was survive 100% in all treatment except in fish feed with ADSPL based diet (96.6%). Fulton’s condition factor of experimental fish was greater than 1 in all treatment. SR and FCR was not affected by tested diets (P > 0.05). However, a significant difference in growth and feed utilization parameters were noticed. Fish fed with control diet showed better weight gain (61.85g), specific growth rate (1.66%/fish/day) and feed utilization efficiency than others except fish fed with yeast fermented sweet potato leaf. Therefore, it can be concluded that the yeast fermented sweet potato leaf meal can be used for O. niloticus feed without any adverse effects on growth performance, feed utilization and body composition.
  • No Thumbnail Available
    Item
    EFFECTS OF PROBIOTIC SUPPLEMENTATION ON GROWTH AND HEALTH PROMOTION OF THE NILE TILAPIA, Oreochromis niloticus (Linnaeus, 1758)
    (HAWASSA UNIVERSITY, 2023-10) KASSAHUN KOYSHA OYATO
    Probiotics have emerged as promising feed additives in aquaculture, offering potential benefits for fish growth and health promotion. This study was intended to evaluate the efficacy of three probiotic strains, Bacillus subtilis subtilis (p1), Bacillus subtilis inaquosorum (p2), and Saccharomyces cerevisiae (p3), on the growth and health of Oreochromis niloticus fingerlings. A total of 300 fingerlings with an average weight of 7.7 ± 0.103g and length of 7.46 ± 0.073cm were randomly divided in to five experimental groups: control (p0), p1, p2, p3, and a combination of all three probiotics (p4). The fish were fed a diet containing 30% crude protein (CP) at 5% of their body weight either with a basal feed (control group, p0) or with probiotic-supplemented feed (p1, p2, p3, and p4 groups at a dosage of 1.5*10⁸ CFU/mL) for 90 days. Water quality parameters, including dissolved oxygen (DO), pH, and temperature, were measured every 15 days, three times a day. Growth performance parameters, including body weight gain (BWG), specific growth rate (SGR), daily weight gain (DWG), feed conversion ratio (FCR), protein efficiency ratio (PER), and survival rate (SR), were assessed at the end of the experimental period. Additionally, gut microbiota analysis, hematological parameters, and proximate composition of fish were evaluated. The results indicated that water quality parameters remained stable throughout the experiment, except for DO, which showed significant differences (P < 0.05) among the groups. The probiotic-supplemented groups (p1, p2, p3, and p4) exhibited significantly higher growth performance parameters compared to the control group (p0). The group fed with Bacillus subtilis inaquosorum (p2) demonstrated the most remarkable growth performance, with the highest BWG (128.4 ± 0.146 g), SGR (2.66 ± 0.015% day⁻¹), DWG (1.43 ± 0.001 g day⁻¹), and PER (4.28 ± 0.004), and the lowest FCR (1.04 ± 0.003) and SR (100 ± 1.291%). Additionally, the probiotic diet effectively eliminated pathogenic microflora, including Salmonella spp., Escherichia coli, and Candida albicans, from the gut of O. niloticus compared to the control group. Hematological examination revealed significantly improved packed cell volume, RBC, hemoglobin, WBC, and differential leukocyte counts in the probiotic-fed groups. Proximate composition revealed better Crude protein, Dry matter and Carbohydrate content in probiotic diet and decreased Moisture, Crude fat, Ash and Crude fiber. In conclusion application of probiotics in aquaculture is crucial to improve growth and health of O. niloticus as well as to improve water quality
  • No Thumbnail Available
    Item
    FEEDING HABITS AND REPRODUCTIVE BIOLOGY OF THE AFRICAN BIG BARB, Labeobarbus intermedius (RÜPPELL, 1836) (PISCES: CYPRINIDAE) IN RIVER BELES, ETHIOPIA
    (HAWASSA UNIVERSITY, 2023-10) HAYMANOT ATENAFU
    Labeobabus intermedius is the 3rd most important fish species in Ethiopian water bodies and the most important in Beles River. The study aimed on reproductive biology, feeding habits and condition factor of L. intermedius were investigated in Beles River based on samples collected from February 2023 to July 2023. The findings of this study were given using figures, Tables, frequency of occurrence, and volumetric methods of analyses. A total of 464 fish samples were caught, ranging from TL 13.5 cm to 49.3 cm and TW 19 g to 1,278 g, for males and TL 11.6 cm to 48.2 cm, and TW of 18 g to 1491 g for females using long lines. Detritus (42.1%), phytoplankton (41.5%), macrophytes (7.2%), insects (4.3%), gastropods (1.5%), and zooplankton (3.4%) were using frequency of occurrence and volumetric analyses, respectively. The overall male-to-female sex ratio was significantly different from 1:1 (χ2 = 4.2*, p<0.01). Lm50 for males and females was 28.6 cm and 26.4 cm TL, respectively. GSI values ranged from 0.15 to 28.8 % for males and 0.1 to 40.43 % for females. The fish breeds throughout the sampling period, with intensive breeding in February. The length-weight relationship was found to be curvilinear (TW = 0.01 TL2.88). The FCF was ranged from 0.4 to 1.02 ± 0.01 for males and 0.38 to 1.004 ± 0.01 for females. In general, FCF and ripe gonad were inversely proportional, and compered to other studies the fecundity L. intermedius in Beles River were relatively high. There was no observable variation in the food items between dry and wet months, but noTable ontogenetic variation was seen in the diet. Fish under 28.2cm should be protected from unwise exploitation. The study offers crucial insights into the ecological role and life history of L. intermedius in the Beles River ecosystem, thereby aiding in its conservation in Ethiopia.
  • No Thumbnail Available
    Item
    i EFFECT OF AQUAPONIC SYSTEMS ON WATER QUALITY, GROWTH PERFORMANCE OF NILE TILAPIA AND GROWTH AND YIELD OF VEGETABLES M.Sc. THESIS
    (HAWASSA UNIVERSITY, 2023-10) JALANE DIDA AKESA
    Aquaculture production is one of an alternative food producing sector. Compared to different alternative ways of aquaculture production, aquaponics system is preferable to mitigate food and nutritional security in Ethiopia. Plants and fish have different growth performances in different culture systems. So the present study was designed to assess how the two aquaponic systems (Media Bed and Nutrient Film Technique) affect the water quality and growth performance of Nile tilapia (Oreochromis niloticus) and their effect on the growth and yield of tomato (Solanum lycopersicum) and lettuce (Lactuca sativa). The study was performed from March to May 2023 (12weeks). Four hundred fingerlings of Nile tilapia (Oreochromis niloticus) of uniform size were obtained from Batu Fish and Other Aquatic Life Research Center and stocked into fish tanks of the experimental units. However, the tomato (Solanum lycopersicum) and lettuce (Lactuca sativa) seeds were purchased from Batu local market, germinated on seedbed and transplanted to the experimental units. The experimental fish were supplied 30% protein content commercial feed twice per day. The water quality parameters such as dissolved oxygen, hydrogen ion concentration (pH), temperature, conductivity and salinity were measured once per two weeks and three times per sampling date. The present study revealed that, pH ranged between 9.26 and 9.45, temperature ranged between 24.63 and 25.7°c, TDS ranged between 1.75 and 1.77 g/L, conductivity ranged between 2.3 and 2.4 mS and salinity ranged between 1.21 and 1.3ppt. WG, FCR, CF, SR, FMTL, and FMBW for the media-filled bed system were 40.36+ 0.19g, 1.2 + 0.0, 2.07+ 0.05, 98.59+0.4%, 14.75+ 0.3cm, and 60.36+ 0.19g, respectively, and for the NFT system, the values were 40.67+ 0.3g, 1.2 + 0.0, 2.18+ 0.3, 98.68+ 0.95%, 14.1+ 0.27cm, and 60.67+ 0.3g, respectively. The water quality parameters and growth performance of the experimental fish between the two systems didn’t show significant differences at 95% confidence interval (P>0.05). However, the growth and yield of tomato and lettuce in MB was significantly different from that of NFT at 95% confidence interval (p< 0.05). Therefore, it was concluded that, the types of the aquaponics systems did not affect water quality, and survival, condition factor, and the growth performance of Nile tilapia, but they did affect tomato and lettuce growth and yield. For good water quality and fish growth, both MB and NFT are recommended, while for better plant growth, MB is recommended.
  • No Thumbnail Available
    Item
  • No Thumbnail Available
    Item
    INFESTATION AND EFFECTS OF ANISAKID NEMATODE PARASITES ON THE NILE TILAPIA (Oreochromis niloticus LINNAEUS, 1758) IN LAKE HAWASSA, ETHIOPIA
    (HAWASSA UNIVERSITY, 2024-10) RIBKA MENTA BALCHA
    Contraceacum species that is genus of Anisakid parasites is the most economically important internal fish parasite,that poses serious problem in culture and capture fisheries globally, as well as consumers. This investigation aimed to evaluate the infestations and certain effects of Contraceacum spp. on O. niloticus L. 1758) in Lake Hawassa. The study used a cross-sectional design from December 2023 to May 2024. A total of 180 O. niloticus were taken from the landing site. To assess the water quality, samples of water were taken fro amora gedel. Infestation peaked in February and April each with 56.6% and lowest in December (40.0%). However, highest intensity of Contracaecum spp. was in May (9.66%) and lowest in January with (4.20%). Prevalence of Contracaecum with sex of O. niloticus were statistically not significant.The size of O. niloticus and the presence of Contracaecum were positively correlated. Hematological effects of Contracaecum on O .niloticus between infested and non-infested group were significant (p<0.05) except for neutrophil count sand basophil (p>0.05). The results of the physicochemical parameters showed statistically significant difference with all parameters except ammonia that showed variation, but not statistically significant (p value=0.294). There were positive correlation between physicochemical parameters and the prevalence of Contracaecum, however, negative correlation with dissolved oxygen (r=-0.002). In conclusion, the temperature of the water influences whether the Contracaecum infestation is high or low, depending on the sampled months. Contracaecum parasite prevalence is also influenced by variations in physicochemical parameters. The high prevalence (37.3%) of Contraceacum spp. in muscles of O. niloticus as compared to varied various body organs indicates that consuming raw fish poses a significant health risk to humans. Therefore,it is crucial to eat the fish only well coocked form, at the encysted larvae present in fish muscle can be transmitted to human hosts.
  • No Thumbnail Available
    Item
    INFLUENCE OF WATER QUALITY ON PARASITE PREVALENCE IN NILE TILAPIA (Oreochromis niloticus Linnaeus, 1758) IN CULTURE SYSTEMS IN SIDAMA REGION, ETHIOPIA
    (HAWASSA UNIVERSITY, 2024-10) BERHANESH ARFICHO BOKORO
    Parasitic infestation can lead to severe retarded growth and mortalities in high intensities in fish under culture systems. Importantly, the quality of water in the culture facility may influence the parasitic infestation. This study aimed to evaluate the influence of water quality on parasite prevalence in Nile tilapia, Oreochromis niloticus L,1758 in culture systems in Sidama Region. The study used a cross-sectional design from December 2023 to May 2024. Water physico-chemical parameters such as temperature, dissolved oxygen, pH and turbidity were measured in situ by following standard procedures. Water samples for nutrient contents such as ammonia, nitrate and nitrite were analyzed. A total of 240 O. niloticus (120 from Kokeb fish farm and 120 from CARE fish farm) were taken and examined in the laboratory for ecto and endo parasites by using stereo zoom dissection microscope. The parasitological aspects such as prevalence, mean intensity and mean abundance were calculated based on standard formulae. The results indicated that, the water quality parameters were significantly different (p<0.05) between both fish farms. The total number of parasite species recorded during the study was 11 species. While Kokeb fish farm showed 11 parasite species, there were only six species in CARE farm. Out of 240 fish sampled, 109 fish were infested representing an overall prevalence of 45.41%, mean intensity of 6.30 and mean abundance of 2.86. The prevalence, mean intensity and mean abundance in Kokeb farm were in the order of 59.16%, 7.46 and 4.41. In CARE farm, it was 31.66%, 4.48 and 1.30 respectively. The infestation showed a statistical difference (p<0.05) between the fish farms. There was a positive correlation between water quality and prevalence of parasite species, except dissolved oxygen. The size of O. niloticus and prevalence of parasite species was positively correlated (r=0.978). Prevalence of parasite species with sex of O. niloticus was statistically significant (x2=2.776, p<0.05). The Fulton’s condition factor of parasitized and non-parasitized O. niloticus showed no significant difference (p>0.05). Hematological effects of parasite species on O. niloticus between infested and non-infested groups were significant (p<0.05) except for neutrophil counts (p>0.05). The prevalence of parasite species was influenced by poor water quality. The study recommends that, to reduce or control parasite infestation in culture systems, there is an imperative need to undertake regular monitoring and management of water quality parameters in fishponds.
  • No Thumbnail Available
    Item
    INTEGRATING FISH FARMING WITH VEGETABLE PRODUCTION: A STRATEGY TO ENHANCE FOOD PRODUCTION, PROFITABILITY AND INCOME DIVERSIFICATION
    (HAWASSA UNIVERSITY, 2023-11) KOKOBE TEFEREDEGN ERGETA
    The growth of human population requires an additional food-producing sector to meet the demand for animal protein sources. Regarding this, integrated fish farming can be considered as an additional option to enhance yield diversification with minimal investment costs. Thus, the present study was conducted to evaluate the integration of a fish farming system with vegetables as a strategy to enhance food production, profitability, and income diversification. The study encompassed both the survey component and the experimental work conducted in this study. The survey component employed visual observations, interviews, and questionnaires to assess the status of fish farming, including productivity, profitability, and constraints, in five districts of Sidama Regional State. The field experiment was conducted at Hawassa University's Centre for Aquaculture Research and Education from February 2023 to May 2023. The experiment involved stocking 150 fingerlings of Oreochromis niloticus with an average weight of 9.8 ± 0.42 g in 80m2 pond, and Swiss chard production used 15 plots measuring 2m x 2m in a randomized complete block design. Swiss chard was grown with five treatments: compost, chemical fertilizer, BSFFF, control, and pond water. Data on fish and vegetable growth parameters, yield, and pre and post- soil properties were collected. Phytoplankton composition in the fish pond and stomachs of experimental O. niloticus was analyzed. The experimental and survey data were analyzed with SAS software Pro13 and SPSS software, respectively at 95% confidence interval. As for the survey results, it was found that 77% of fish farmers harvest fish for both consumption and commercial purposes, contributing to food security and income. However, constraints limit the adoption of integrated fish farming in the surveyed districts. Still, both IAA and non-IAA farmers exhibit a positive attitude toward fish farming. The Field experiments demonstrate O. niloticus achieved a final body weight of 98.6±4.9g. Swiss chard treated with fish pond water showed significant growth improvement in leaf length, leaf width, and leaf number (P<0.05) compared to all treatments except BSFFF. Marketable yields from plots treated with pond water were comparable to other treatments but significantly higher than the control (P<0.05). Post-harvest soil analysis revealed that the application of fish pond water treatments improved the physicochemical parameters of the experimental soil. Among the identified phytoplankton groups, Bacillariophyceae and Chlorophyceae were found to be dominant in the stomach of O. niloticus, with varying abundance in genera. Cost-benefit analysis of the system revealed that Swiss chard treated with pond water showed higher profitability compared to other treatments. Based on the obtained results, it is recommended to promote the practice of integrated fish farming systems to enhance diversified yield, income generation, and sustainable agriculture.
  • No Thumbnail Available
    Item
    REPRODUCTIVE BIOLOGY AND FEEDINDG HABITS OF THE NILE TILAPIA OREOCHROMIS NILOTICUS (L. 1758) (PISCES: CICHLIDAE) IN DAMTE DAM, WOLAITA ZONE SOUTHERN ETHIOPIA
    (HAWASSA UNIVERSITY, 2024-10) ERMIAS SHIRKO BIRBIRE
    Reproduction, feeding and condition factor of O. niloticus were investigated in Damte Dam based on the samples collected from February, 2024 to September, 2024. A total of 584 fish samples were caught ranging from 10 cm to 33.9 cm TL and 32 g to 750 g TW for males and 9.7 cm to 33.9 cm TL and 32.1 g to 421 g TW for females. The aim of this study was to investigate reproduction and feeding habits of O. niloticus in Damte Dam, Ethiopia. The overall male to female sex ratio was significantly different from 1:1 (ꭓ2=4.281, p<0.05). Lm50 for males and females were 14.7 cm TL and 13.9 TL cm, respectively. GSI values ranged from 0.26 to 1.59 for males and 0.25 to 1.8 for females. The fish bred throughout the sampling period with intensive breeding months in May, June and July. The length weight relationship was found to be curvilinear (TW = 0.0105TL3.1988). ACF value of male was minimum values of 0.40 to maximum value of 2.99 with a mean of 0.933 ± 0.013 and females O. niloticus ACF was ranged from 0.75 to 2.77 with mean value of 1.39 ± 0.016. Detritus (94.61%, 34.53%), macrophytes (88.41%, 29.59%), phytoplankton (85.18%, 31.36%), insects (18.33%, 2.61%) and zooplankton (11.59%, 1.90%) were using frequency of occurrence and volumetric analyses respectively. In general, ACF and ripe gonad were inversely proportional, and compared to other studies. The fecundity of O. niloticus in Damte Dam was relatively low. There was no observable variation in the food items between dry and wet months, but notable ontogenetic variation was seen in the diet. O. niloticus under 15 cm TL should be protected to save the breeding fish from the risky fishing of locals. The study emphasizes the importance of raising public awareness about the value of using fisheries resources to improve local communities' living standards and research on Damte Dam conservation
  • No Thumbnail Available
    Item
    THE EFFECT OF TIN DOPING ON THE STRUCTURAL AND OPTICAL PROPERTIES OF COPPER OXIDE THIN FILMS SYNTHESIZED BY USING CHEMICAL BATH DEPOSITION METHOD
    (HAWASSA UNIVERSITY, 2024-11) AHMED HUSSIEN TOLA
    This thesis studied the effect Tin doping copper oxide thin films synthesis by chemical bath deposition method. The deposition of thin film was done on glass substrate by changing the tin chloride solution as 0ml, 2ml, 4ml and 6ml. The deposition of thin film was done by using 0.4M of copper acetate as Cu source and 5ml Ammonia to control the PH value 3ml of Hydrazine as a comp lexcing agent at constant temperature of 50℃ and constant time of 25 minute. The structural and optical properties were studied by using XRD and UV VIS technologies. The XRD patterns show two phase that CU2O which have cubic crystal structure and Copper mono oxide which have monoclinic crystal structure. The crystallite size of the cubic Cu2O phase deposited at 0 ml, 2 ml and 4 ml SnCl2 was 38.51, 33.44 and 37.74 nm respectively. The crystallite size of the CuO phase deposited at 2 ml, 4 ml and 6 ml SnCl2 are 11.75, 77.6 and 15.99 nm respectively. The intensity was decrease as the doping level increase in both Cu2O and CuO. The UV-VIS investigation revealed the three energy band gap result when2ml, 4ml and 6ml of tin chloride added to the solution the energy band gap observed between wave length of 400-800 nm shows at 2ml 1.7ev,at 4ml 1.9ev .and at 6ml 2.05ev.