• Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.344-354
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• 2023

Food and feeding habits of large cyprinid fishes (Labeobarbus intermedius, Labeobarbus nedgia, and Labeo forskalii) had been investigated in the upper Blue Nile River, Ethiopia. Four sampling sites were selected and specimens were sampled during the post-rainy (November 2016) and dry (March 2017) seasons by gillnets of 6 cm, 8 cm, 10 cm, 12 cm, and 14 cm mesh sizes. Totally 401 fishes were collected and about 30.4% (122) of the samples were documented with empty guts and 279 (69.6%) of them were with non-empty guts. The whole contents of all non-empty gut specimens were taken, labeled, and preserved using a 5% formaldehyde solution for further analysis. In the laboratory, gut contents were examined and identified using compound and stereo microscopes. The relative importance of different food items in the diet compositions was analyzed using a frequency of occurrence and volumetric analysis. During the post-rainy season, insects and phytoplankton were mostly ingested as food items. However, during the dry season, phytoplankton was the most important food item in the diet of all cyprinid fishes of the river. Based on current study results, L. intermedius and L. nedgia might be omnivores in their diet but Labeobarbus forskalii seemed to be detritivorous.

• Journal of Ecology and Environment
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• 제42권3호
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• pp.128-138
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• 2018

Background: This study investigated the variation of soil organic carbon in four land cover types: natural and mixed forest, cultivated land, Eucalyptus plantation and open bush land. The study was conducted in the Birr watershed of the upper Blue Nile ('Abbay') river basin. Methods: The data was subjected to a two-way of ANOVA analysis using the general linear model (GLM) procedures of SAS. Pairwise comparison method was also used to assess the mean difference of the land uses and depth levels depending on soil properties. Total of 148 soil samples were collected from two depth layers: 0-10 and 10-20 cm. Results: The results showed that overall mean soil organic carbon stock was higher under natural and mixed forest land use compared with other land use types and at all depths ($29.62{\pm}1.95Mg\;C\;ha^{-1}$), which was 36.14, 28.36, and 27.63% more than in cultivated land, open bush land, and Eucalyptus plantation, respectively. This could be due to greater inputs of vegetation and reduced decomposition of organic matter. On the other hand, the lowest soil organic carbon stock under cultivated land could be due to reduced inputs of organic matter and frequent tillage which encouraged oxidation of organic matter. Conclusions: Hence, carbon concentrations and stocks under natural and mixed forest and Eucalyptus plantation were higher than other land use types suggesting that two management strategies for improving soil conditions in the watershed: to maintain and preserve the forest in order to maintain carbon storage in the future and to recover abandoned crop land and degraded lands by establishing tree plantations to avoid overharvesting in natural forests.