1,720,981 research outputs found
Assessment on handling practices and post-harvest loss of fish in Lake Ardibo, South Wolo, Tehuledere Woreda Ethiopia
No full textEthiopia has substantial fishery resources in the inland lakes and rivers with potential yield
of more than 94500 tons per year from the main water bodies like Lakes Tana, Ziway,
Langeno, Hawassa, Chamo, Abaya and manmade reservoirs. The fishery sector of Ethiopia is
not well developed regarding post-harvest handling practice due to fish post-harvest
handling practices and loss are the bottlenecks in fisheries sector. The present study was
aimed to assess handling practices and estimate postharvest losses at Lake Ardibo located in
Tehuledere Woreda, South Wolo, Amhara Regional State. The data was collected from
October, 2018 to May, 2019 using three methods (Informal fish loss assessment methods,
Load track methods, and Questionnaire loss assessment method) from all the registered
members of the fishermen cooperatives. Questionnaires, observations and participatory rural
appraisal were used to collect primary data and additionally secondary data were collected
from Tehuledere Woreda, Agricultural office. All of the fishermen were male and 96.32% of
them were married. About 33.87% ranges between 6-10 years of experience and 31.02 %
ranges between 11-15 years of experience. 40% of the respondents were first cycle (1-4)
grade level, 29.79 % were 5-8 grade level and 16.73 % were illiterate. A total of 149463 kg
fish was harvested in last year, from these 13574 kg fish was lost. The average weekly and
daily fish production was 1542.4 kg and 529kg, respectively and also the average weekly and
daily loss of fish was141.4kg and 23.63kg, respectively. The major factors for loss were
absence of market linkage between fishermen and traders, lack of enough refrigerators,
distance of the lake from town and lack of transportations. Market force loss that leads to
both quality and physical loss were dominant at Lake Ardibo. A significant correlation was
found between the amount of fish post-harvest lose and the explanatory variables like major
factors for PHL, storage time of fish and fishing experience with (R=0.951, do = 7, p
<0.001). At the study area in every 200kg harvested fish 17.5kg fish was lost and totally
13574 kg fish postharvest loss was recorded due to this the fishermen cooperatives lost
1,357,400birr. This calls for effective postharvest management of fish from harvesting to
consumption
Impact of species and environment on the distribution of nutrients in fish
No full textAquatic food production plays a pivotal role in providing food, nutrition, employment,
recreation, trade and economic well-being for people throughout the world, for
present and future generations. It offers a life-changing opportunity for the hundreds
of millions of undernourished people around the world, particularly in low- and
middle-income countries. Moreover, aquatic food production is one of the candidate
sectors recently foreseen as fortification of nutrient-sensitive agriculture. Aquaculture
is continuously increasing worldwide to meet the global market demand for fish and
fishery products, driven by the increasing human population and over-exploitation of
wild capture fisheries. Though overexploitation of wild capture fisheries has been
reported, still it dominates the fish supply in Africa, and aquaculture production in the
continent contributes an insignificant percentage. To sustain aquatic food production,
there would be a diversifying option of fish species and parts used for human
consumption (Chapter 1).
People have never consumed as much fish nor depended so much on the aquatic food
products for their livelihoods. As a matter of fact, micronutrient deficiency is affecting
most developing countries. In such condition, diet shift towards diverse fish species
could be a sensible remedy for micronutrient deficient nations. In Ethiopia, both
capture and culture fisheries are focusing on a relatively narrow diversity of fish
species, which likely underutilizes the nation’s aquatic resources for food and nutrition
provision, because fish species vary considerably in their nutrient composition and
density. Given the wide diversity of aquatic life, fish nutritive value, especially mineral
concentrations could be influenced by various factors, such as species, habitat, climate,
and tissue characteristics (metabolic activity and homeostasis). Therefore, investigating
the impact of these factors in nutritive value, essential and non-essential mineral
concentrations in different fish species and tissues is paramount in the aquaculture
sector development. The general aim of this PhD thesis thus was to investigate the
impact of species, tissues and ecosystem on the nutrient metabolism and nutritive
value of fish as part of a nutrition- sensitive agriculture (Chapter 2).
Bayissa T.N. 2021
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Fish nutrient deficiency should not occur when diets have been formulated and
prepared based on the species’ requirement. However, some commercially available
diets for another species may sometimes be used in the absence of a suitable
formulation, resulting in deficiencies. Chapter 3 compared micromineral (Fe, Zn and
Cu) homeostasis across ten ornamental fish species. Ten different species of live
ornamental fish were randomly sampled from one big aquarium in a pet store in
Belgium. All fish samples were dissected manually for the collection of targeted tissues
and analyzed for the above mentioned microminerals. In general, muscle tissue
showed the lowest concentrations for each of the three microminerals in all species,
still with important variation among species. Fe was associated with Cu in muscle tissue
(p < 0.05), but neither of them were associated with Zn in the muscle. However, the
three micromineral concentrations were correlated in the heart (p < 0.05). Similarly, all
of them were correlated in the liver (p < 0.05), but none of them showed a significant
association in the tail fin. Excess deposition of minerals in heart tissue is a new
observation, and it is not known if this is meant as storage or rather the fish heart has
a high requirement for microminerals. Storage in the tail fin should be interpreted as
a sign of permanent deposition as a tool to dispose of toxic excess. The lack of
correlation between the muscular concentrations of Zn on the one hand, and those of
Fe and Cu on the other hand, further suggests that fish species distinctly differ in their
micromineral metabolism. Although this exploratory study still leaves many questions
unanswered, it points to the large diversity in micromineral metabolism among fish
species.
Consequently, Chapter 4, aimed to evaluate the macronutrient and mineral
composition of whole fish (Labeobarbus intermedius, Garra quadrimaculata) and fillet
(Oreochromis niloticus, Labeobarbus intermedius) from the same water body. A total
of 64 fish samples were collected from Gilgel Gibe reservoir, Ethiopia, and analyzed for
its macronutrient and mineral composition. The proximate composition and mineral
contents of fillets and whole body samples were determined. The whole fish showed a
much higher fat and ash percentage than the fillets (p<0.05). The fillets contained a
Bayissa T.N. 2021
180
much higher protein concentration than the whole fish (p<0.05). The higher Ca: P ratios
in whole fish compared to fillet in our study confirms the importance for a healthy
human skeletal development, especially in diets where Ca is typically lacking. Whole
Garra appeared to be containing important trace elements such as zinc and iron, a
feature that was not found to the same extent in the whole Labeobarbus. These
differences may find its origin in the feeding pattern of these fish species in the
reservoir. The advantage of benthic species such as Garra to enrich the human diet
with essential minerals may, however, coincide with the accumulation of toxic heavy
metals as a potential result of soil erosion.
In natural conditions, the distribution of minerals can vary with the local activity
(farming, industrial, or urban activity) that limits the resealing rate of effluents into the
nearby aquatic environment. The accumulation and distribution of beneficial and toxic
trace elements in fish tissues can be affected by the mineral load in its environment
and diet, which, in turn, will be a reflection of soil composition and geological events,
such as soil erosion. In Chapter 5, a study was aimed to evaluate the differences in
mineral and toxic trace element concentrations of Nile tilapia tissues from three
aquatic ecosystems in Ethiopia namely, Lake Ziway, Lake Langano, and Gilgel Gibe
reservoir with a focus on edible (fillet) and discarded (digestive tract, gills, skin, and
liver) parts. From each lake, twenty Nile tilapia samples were collected, dissected for
the targeted tissues and analyzed by inductively coupled plasma mass spectrometry.
All elements varied markedly among tissues and between the lakes. Some differences
in element concentrations were attributed to differences in nutrient load in the
ecosystems and the function of the tissues. For instance, the calcium concentrations in
skin and gill were distinctly higher in fish from calcium-rich Lake Langano. The
discarded parts were richer in essential trace elements, showing an opportunity to
promote their use in human nutrition to increase the intake of important minerals.
However, the accumulation of elements toxic to humans, such as aluminum, should be
monitored and controlled when rearing these fish in aquaculture.
Bayissa T.N. 2021
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A natural aquatic ecosystem harbors a diversity of factors, making it hard to identify
the most limiting factors for fish development and body composition. In Chapter 6,
study was conducted to explore how metabolite analysis can mechanistically explain
differences in tissue composition and size of Nile tilapia from different habitats. Dried
blood spot (DBS) samples of Nile tilapia were collected from three Ethiopian lakes
(Gilgel Gibe, Ziway, and Langano) and analysed for the carnitine esters and free amino
acids. Metabolite ratios were calculated from relevant biochemical pathways that could
identify relative changes in nutrient metabolism. Marked differences were observed in
Nile tilapia metabolic activity between the lakes. For instance, the lower body weight
and body condition of the fish in Lake Langano coincided with several metabolite ratios
pointing to a low flow of glucogenic substrate to the citric acid cycle. In the Gilgel Gibe
fish, the metabolic markers for lipogenesis and metabolic rate could explain the high
fat concentration in several parts of the body. The nutrition-related blood metabolite
ratios are useful to understand the underlying metabolic events leading to the habitatdependent
differences in growth of Nile tilapia, and by extension, other species.
In conclusion (Chapter 7), this thesis demonstrates the potential for targeted
enrichment of the human diet with minerals and other nutrients through fish. Apart
from the fish diet and environment, the choice of the fish species and which parts are
eaten are available strategies to that end. Whole blood metabolic profiling in fish
showed to be a valuable tool to facilitate and speed up the evaluation of these
strategies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Stock Assessment of Nile Tilapia (Oreochromisniloticus, L.) in Gilgel Gibe Reservoir, Omo-Turkana Basin, Southwest Ethiopia
Full text linkStocks assessment is the first step to determine the level of tolerable exploitation for
arriving at maximum sustainable yields from fish resources. Assessment of stocks and study of
impact of present level of exploitation on exploited stocks are necessary for maintenance of
stocks at maximum sustainable level. A stock assessment of Gilgel Gibe fisheries has never
been conducted despitethe reservoir’sfishery importance to the local people. In the
presentstudy, length based stock assessment approach was used in order to estimate vital
parameters such as fish growth and mortality. A length-based Thompson and Bell model
(Thompson and Bell, 1934) was used for analysis of yields and long-term yieldpredictions. Nile
Tilapia, Oreochromisniloticus, is one of important commercial fish in Africa and other tropical
regions. InEthiopia, it accounts for more than 60% of the total annual landings.A total number
of 25,994 specimens of Nile tilapia werecollected from March, 2020 to July, 2021. Stock
assessment software FISAT II was used to compute and analyse all the basic parameters and
functions. The estimated current annual yields were 251.07 tons /year. The average annual
recruitment in the reservoir was 121,955 fish. The mean value of growth parameters The L∞
and K values were determined to be 46.67cm and 0.280, respectively, at Rn value of 0.174. The
fish growth performance index (Φ'), computed from the fish growth rate and the asymptotic
length, was 2.79. Estimation of current rate of exploitation of yield and biomass was 6.48 tons
and 28.12 tons respectively. Therefore harvest level should be decrease from maximum
sustainable yield to maintain and recover highly depleted biomass.The stock biomass at the
current level of exploitation has already declined to 26.32% of the biomass at the unexploited
stock. Therefore, there is an urgent management need to regulate fishing effort in order to
safeguard the resource and thereby ensure its sustainability and the livelihood of the
community that depends on it for its livelihood
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Assessment of Factors of Post-Harvest Fish Losses in the Gilgel Gibe Dam I Reservoir, Sokoru Woreda, Jimma Zone, Southwest Ethiopia
No full textFish is a vital source of protein, essential fatty acids, and micronutrients, playing a crucial role in food security
and economic stability in developing countries. However, post-harvest fish losses (PHFL) significantly affect
both availability and profitability of fish in local markets, with global estimated loss of 10-12 million tons
annually, accounting for 10% of total fish production. While small-scale fisheries in developing countries
contribute nearly half of the world's total fish supply, they face challenges such as post-harvest losses, illegal
fishing, and overfishing. This study aimed to assess factors contributing to post-harvest fish losses in Gilgel
Gibe-I Reservoir in Jimma Zone, Sokoru Woreda, South West Ethiopia, using questionnaire, interview and field
observations from cooperative fishermen. All the study participants were male, with 85.5% being single and
14.5% married; 73.5% were aged 18-25 years, 25% were 26-35, and 1.5% were 36-45 years old. In terms of
education, 95% had only primary-level education, while 5% attended high school. Regarding occupation, 73%
were fishermen, and 27% were fish traders, with 45.5% having two years of experience, 36% one year, 17%
three years, and 1.5% four years. The estimated average weekly fishermen production was 250kg and 45kg
weekly loss due to various factors. The study identified key factors contributing to post-harvest losses,
including lack of market linkages between fishermen and traders, lack of storage materials, insufficient
refrigeration, poor market accessibility, and inadequate transportations. About 53% of the respondents store fish
for 1-2 days before selling, while 47% stored fish less than a day, and although all respondent washed fish
after harvested, 56% had never received formal training on best fishing practices. Furthermore, 80% of
fisherman at Gilgel Gibe reservoir, didn’t take immediate preservation measures at landing site, exacerbating
post-harvest losses. These challenges highlight the urgent need for effective interventions by government
authorities and stakeholders to improve market access, infrastructure, training, and preservation techniques,
ensuring better economic outcomes and food security.Key supporting actors including the oromia Agricultural
research institute, Sebeta fishery research institute, Gilgel Gibe hydroelectric power and Jimma University, all
of which play vital roles in delivering these service
Effect of various supplementary feedings on growth of Nile Tilapia (Oreochromis niloticus) in concrete ponds
No full textThe study was conducted to evaluate the effect different supplementary feeding of wheat flour, noug cake and maize flour on the growth performance of Oreochromis niloticus in concrete ponds at Zeway fisheries resources research center. The feeding trial was conducted in three ponds of having a surface area of 35m 2 each for seven months between July 2012 and January 2013. All the experimental and control group were run in triplicate with stocking density of 3fish/m 2 . The supplemental feeds were agreed at 5% of the fish body weight with respective test feeds and the control group was without any supplemental feed. The initial weight (33.3gm) and length (12.5cm) of O. niloticus, in all treatments was not noted as statically different. The results of study indicated that, the final weights were significantly different among the treatments. Generally, fish fed with supplementary feeds grew significantly higher than the unfed (Control group) group (ANOVA, P<0.001). Similarly, growth of the fish fed with wheat flour + noug cake (WF+NC) showed significantly higher growth performance than the fish fed with maize flour + noug cake (MF+NC) (ANOVA, P<0.05). Fish rose in WF+NC (0.35 g/day) demonstrated better growth rate than MF+NC (0.15g/day). Variation in growth rate between fed treatments and unfed treatment as well as among fed treatments might be attributed to both direct and indirect effects of supplementary feeds given to the fish. Direct intake of feeds by the fish provides more nutrients resulting in better growth and production
Identification of bacterial flora for the Nile Tilapia (Oreochromis niloticus) fillet product sold in fish markets of Jimma, Ethiopia
No full textA research exercise was undertaken on isolation and identification of bacteria associated with
packed fillets of Nile Tilapia fish (Oreochromis niloticus) sold at Jimma town, Oromia,
southwest of Ethiopia since March, 2015 to June, 2015. Tissue sections (fillets) of randomly
selected Nile Tilapiafishes were studied upon. A serial dilution up to 104 was carriedout, and
studied on nutrient agar. A total of four bacterial families were isolated and identified as
Staphylococci, Enterobacteriaceae, Coliform, and aerobic mesophilic bacteria. Out of 73
isolates, 24 isolates were found as Gram positive and 49 were Gram negative; 22 cocci while 51
isolates were identified as rod shaped; 10 isolates were found to have endospore whereas 63 of
isolates were non-spore forming bacteria; and 67 of isolates were catalase positive with only 6
catalase negative isolates. The number of colony counted from the plate indicated that
Enterobacteriaceae were identified as the highest load (8.92x106CFU/ml), while Staphylococci
the least (2.755x106CFU/ml). The mean bacterial load of isolates (6.1x106 CFU/ml) was found to
be markedly higher than the recommended public health and standard value (5.0 x 106 CFU/ml)
which has been adopted by most countries
Exploring optimum production conditions and nutritional quality of black soldier fly larvae using local bio-wastes for potential use as fish feed in southwest Ethiopia
No full textLack of good-quality and sustainable fish feed is one of the bottlenecks for aquaculture
development in Ethiopia. Therefore, the study aimed to explore the optimal production conditions
in terms of substrate type, feeding rate, feeding frequency, days for maturity, and nutritional
quality of black soldier fly (BSF) larvae using local bio-wastes as potential fish feed in southwest
Ethiopia. The study involved two trials. The first experiment assessed the effects of local feed
ingredients (poultry manure, brewery waste, and rumen liquor) at different feeding rates (100, 150,
200, and 250 g feed/g larvae/day) on BSF larvae biomass production, growth rate, bioconversion
rate, waste reduction efficiency, and days for maturity. The amount of substrate added, total
weight, dry weight, initial and final larval biomass and maturation time was recorded. Then the
recorded data was statistically analyzed using a two-way ANOVA to establish statistical
significance among the groups. Brewery waste was found to be the most effective feed ingredient
at 100 g feed/g larvae/day feeding rates, which resulted in the highest larval biomass production
(12.2 ± 1.03 g), bioconversion rates of 5.19% to 7.89%, and substrate reduction rates of 40.59%
to 46.75%. The second experiment examined the mixed feedstocks with varied feeding regimes
(daily, midweek, weekly, and lump sum). The best performance was observed on a mixture of
poultry manure (Pm) and brewery waste (Bw) with equal proportions (50:50) applied at lump sum
feeding regimes. It produced the highest larval biomass (11.05 g), bioconversion rates of 15.48%
to 22.78%, and waste reduction rates of 30.92% to 36.54%. The proximate composition of larvae
also varied according to the feed ingredient and feeding strategies; the maximum crude protein
(CP) content of 46.5% was shown on larvae reared on poultry manure and brewery waste mixed
in equal proportions (50:50), whereas the lowest CP content of 39.7% was observed on larvae
reared on rumen liquor. The present study paves the way for a more sustainable and localized
approach to fish feed production for aquaculture development in Ethiopia, fostering economic
growth, environmental stewardship, and improved food security
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