Gebremedhin Shewit- Aquatic ecology
- Ghent University
Gebremedhin Shewit
- Aquatic ecology
- Ghent University
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28
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Introduction
Current institution
Publications
Publications (28)
The effects of land-use change on ecosystem services in Kurt Bahir wetland were investigated during 2013 to 2014 using LANDSAT satellite images from 1973, 1986, 2002 and 2013 to identify and map changes in land-use classes over time. To understand perceptions of changes in ecosystem services that resulted from observed land-use changes discussions...
Fisheries play a significant role in the livelihoods of the world population, while the dependence on fisheries is acute in developing countries. Fisheries are consequently a critical element for meeting the sustainable development (SDG) and FAO goals to reduce poverty, hunger and improve health and well-being. However, 90% of global marine fish st...
Lake Tana is the largest lake in Ethiopia with an area of 3050 km² and a catchment area of about 16,000 km². The lake is one of the 250 lakes identified as priorities for biodiversity conservation and is home to the world's unique Labeobarbus species flock. The 18 species of the genus are the only remaining cyprinid species flock in the world after...
The migratory and endemic Labeobarbus platydorsus and Labeobarbus tsanensis are threatened by extinction. This study is the first to use otolith microstructural analyses to infer life history traits of these species to assist in future conservation. We examined whole asterisci otoliths from 750 L. tsanensis and 542 L. platydorsus collected monthly...
This study was conducted from March 2013 to January 2014 to evaluate and compare selected technologies for quality fish produce. Two trial sites were selected based on the local experience of traditional fish drying, market accessibility, and better fish catches. For each site, one fishers’ research group with 15 members was selected. The moisture...
Although validation of the rate of growth zone deposition is a prerequisite for accurate age estimation, such studies are non-existent for the endemic Labeobarbus species in Lake Tana. Therefore, the aim of the current study was to validate the periodicity of growth zone deposition in asteriscus otolith of L. tsanensis and L. platydorsus. A total o...
The analysis of fish age data is vital for the successful conservation of fish. Attempts to develop optimal management strategies for effective conservation of the endemic Labeobarbus species are strongly affected by the lack of accurate age estimates. Although methodological studies are key to acquiring a good insight into the age of fishes, up to...
The endemic Labeobarbus species in Lake Tana are severely affected by anthropogenic pressures. The implementation of fisheries management is, therefore, vital for their sustainable exploitation. This study aimed at investigating the catch distribution and size at 50% maturity (FL50%) of the Labeobarbus species. Samples were collected monthly from M...
Lake Tana, Ethiopia’s largest lake, has a remarkable and conservation-worthy assemblage of fish species, requiring fisheries management for sustainable exploitation. However, due to anthropogenic impacts, many of these fish species are threatened. Hence, an improved management of these resources is recommended. To allow a more sustainable exploitat...
Lake Tana has a remarkable fish diversity, including 17 endemic Labeobarbus species, of which nine spawn in the inflowing rivers. Three of the migratory species are threatened, namely the endangered Labeobarbus macrophtalmus and the vulnerable L. acutirostris and L. platydorsus. In July–November 2016 during the wet season netting upstream and downs...
The effects of land-use change on ecosystem services in Kurt Bahir wetland were investigated during 2013 to 2014 using LANDSAT satellite images from 1973, 1986, 2002 and 2013 to identify and map changes in land-use classes over time. To understand perceptions of changes in ecosystem services that resulted from observed land-use changes discussions...
The effects of land-use change on ecosystem services in Kurt Bahir wetland were investigated during 2013 to 2014 using LANDSAT satellite images from 1973, 1986, 2002 and 2013 to identify and map changes in land-use classes over time. To understand perceptions of changes in ecosystem services that resulted from observed land-use changes discussions...
The effects of land-use change on ecosystem services in Kurt Bahir wetland were investigated during 2013 to 2014 using LANDSAT satellite images from 1973, 1986, 2002 and 2013 to identify and map changes in land-use classes over time. To understand perceptions of changes in ecosystem services that resulted from observed land-use changes discussions...
The effects of land-use change on ecosystem services in Kurt Bahir wetland were investigated during 2013 to 2014 using LANDSAT satellite images from 1973, 1986, 2002 and 2013 to identify and map changes in land-use classes over time. To understand perceptions of changes in ecosystem services that resulted from observed land-use changes discussions...
Sand and gravel materials are often used in Ethiopia's construction sector. However, the impacts of sand mining on the water body's habitat and biodiversity are not yet considered in the country. In this paper, we study how sand mining activities at Lake Tana and its inflowing rivers affect the environment and spawning grounds of the endemic Labeob...
The study was conducted with the main objective of determining the effect of Bahir Dar municipal effluents on water quality of the head of Blue Nile River. Physico-chemical parameters were measured at seven points, whereas aquatic macro invertebrates were sampled at six sites. A total of 6813 aquatic macro-invertebrate individuals belonging to 30 f...
This study was conducted from March 2013 to January 2014 to evaluate and compare selected technologies for quality fish produce. Two trial sites were selected based on the local experience of traditional fish drying, market accessibility and better fish catches. For each site, one fishers’ research group with 15 members was selected. The moisture c...
The study was conducted in 2013/14 with the objective of determining the effects of Bahir Dar textile factory effluents on the head of Blue Nile River water quality. Dissolve oxygen was higher at the upstream site of the river, whereas BOD5, TDS, and total alkalinity values were higher at wastewater outlet of the factory site. The mean values of di...
The reproductive biology of Labeobarbus species in Arno-Garno River was studied from July 2010 to June 2011. Fish were sampled monthly in the non-peak spawning season and twice in the peak spawning season using 6, 8, 10, 12 and 14 cm mesh size gill net. A total of 1077 Labeobarbus specimens were collected within the six sampling months from all sam...
The main purpose of this study is to generate scientific information about some biological aspects of fishes in Aveya River. The study was conducted in 2011/12 both in dry and wet seasons. Sampling sites were selected by considering, nature and velocity of the flowing river, accessibility, fishing activity and human interference. Abiotic parameters...
In the present study we evaluate the diversity and abundance of fishes in Aveya River during the wet season (September-October 2011) and dry season (March-April 2012). Fishes were collected from seven sampling sites by using multi-mesh gillnets of stretched mesh sizes 6, 8, 10, 12 and 14 cm. Eight hundred six fish specimens, all belonging to the Cy...
The main aim of the study is to investigate the spawning migration and some biological aspects of Labeobarbus species. Fish were sampled monthly in the non-peak spawning season and twice in the peak spawning season using gillnets and Monofilament. A total of 832 Labeobarbus specimens were collected from all sampling sites. Out of the total catch of...
The study was conducted from June 2011 to November 2012. We investigated the contribution of Lake Tana fisheries to the livelihoods of the people living around the lake. Random sampling techniques were used to select respondents. In total 145 respondents were drawn. The data were analysed using descriptive statistics, one way ANOVA and correlation...
The spawning migration of Labeobarbus species of Lake Tana to Arno-Garno River was studied from July to December 2010. Five sampling sites, based on the nature, flow-rate of the river, human interference and suitability for fish spawning were selected by preliminary survey. Fish were sampled monthly in the non-peak spawning season (July, November a...
Questions
Questions (5)
I need to use periodic logistic regression (Bernard D. Flury and Edward P. Levri, 1999) to test the periodicity of growth zone deposition in an otolith. Therefore, is there anyone who can give me some insight on how to run this regression in r?
I have 20 independent variables regarding the practices and attitude of fishers about fisheries management. Data was collected though questionnaire and recorded as YES/NO. I would like to identify the variables that have less contribution towards fisheries management. Is there anyone who can suggest me what kind of analysis to use? Do you think that PCA is appropriate?
I have a one year data of catch per unit effort (i.e. fisheries data). The data contains many true zero values and it is right skewed. Thus, I need to run delta Log-normal GLM in order to compare the catch per unit effort (CPUE) across sampling locations and seasons. The dependent variable is CPUE in Kg , whereas, the independent variables are location (four sampling sites) and season (dry and wet). However, I faced a problem to run this in SPSS. Therefore, is there anyone who can suggest me the procedures please?
To see if fish species distribution is dependent on area, I have collected fish sample for one year from four selected sampling site of a given lake. Thus, ten fish species were recorded from all sites. Hence, I used a two way classification chi square to see the difference of the species distribution among the sampling sites and I had got significant difference. However, could not able to see which site is significantly different from which other sites. Therefore, is there anyone who can give me some explanation about this.
Any researcher in the field of fisheries.
