This study was conducted to evaluate the effects of different inclusion levels of water hyacinth ... more This study was conducted to evaluate the effects of different inclusion levels of water hyacinth leaf meal fermented with Aspergillus niger on feed utilization efficiency and growth performance of Nile tilapia (Oreochromis Niloticus L.). Fermented water hyacinth leaf (FWHL) at 0, 10, 20 and 30% inclusion levels were incorporated into four isonitrogenous (35% CP), and isoenergetic (18 KJ g-1 g) test diets. The fishes were stocked in 80 liters aquarium units, in a closed, recirculating indoor system. The diets were fed to triplicate groups of fish fingerlings (1.6 g average body weight) twice a day, at 6% of body weight/day, for three months. The study demonstrated that Nile tilapia fed FWHL at levels 30% had a significant negative impact (P<0.05) on weight gain, specific growth rate, feed utilization efficiency, and whole body composition. But, there were no significant changes between diets supplemented with 10% and 20% FWHL when compared with the control group. Therefore, supple...
This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Eth... more This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Ethiopia, with emphasis on potential spatial, size and seasonal effects on ingested food items. This study of the food and feeding biology of O. niloticus in Lake Langeno, Ethiopia, was conducted from March 2016to February 2017. Fish samples were collected monthly from six different sampling sites using different mesh sizes of gillnets. A total of 610 fish specimens with full stomachs were considered for the assessment of feeding biology. In total, seven food items, namely phytoplankton, zooplankton, insects, detritus, macrophytes, fish parts and nematodes, were identified from the fish stomach contents. Phytoplankton was the most commonly consumed food prey, followed by detritus, zooplankton and macrophytes. The other food items were occasionally and randomly consumed. Phytoplankton and detritus were the dominant food prey in the dry season, with zooplankton and macrophytes the main prey d...
International Journal of Sciences: Basic and Applied Research, 2017
This experiment was conducted to explore the effects of chemical and organic fertilizers at diffe... more This experiment was conducted to explore the effects of chemical and organic fertilizers at different levels of stocking density on the growth performance and yield of Nile Tilapia (Oreochromis niloticus (Linnaeus, 1758)) in earthen pond culture in southwestern Ethiopian highland located at an altitude of 1700 m above sea level. The ponds were divided into control and treatment with diammonium phosphate (DAP) and poultry manure application at three levels of stocking densities as 1, 2 and 3 fish m in a completely randomized design. All the experimental ponds had two replicates. The fertilizers were applied to the treatment ponds at a rate of 2 g m per week for 150 days. Juveniles with mean initial weight of 20.9 ± 0.19 g and mean initial length of 11.51 ± 0.16 cm were stocked. -----------------------------------------------------------------------* Corresponding author. International Journal of Sciences: Basic and Applied Research (IJSBAR) (2017) Volume 32, No 2, pp 80-94 81 The res...
International journal of ecology and environmental sciences, 2015
We investigated the food and feeding habits of Nile tilapia, Oreochromis niloticus, in Lake Hayq,... more We investigated the food and feeding habits of Nile tilapia, Oreochromis niloticus, in Lake Hayq, Ethiopia from August 2008 to March 2009. A total 931 fish were collected by gillnets of various stretched mesh sizes, of which 326 individuals of Oreochromis niloticus stomachs contained food. The stomach contents were analyzed using frequency of occurrence, numerical methods and the Geometric Index of Importance (GII). The food items in the stomach covered a wide variety, ranging from various types of phytoplankton to zooplankton and to macrophytes. The major food items in terms of frequency of occurrence were Microcystis (87.7%), Cosmarium (65.13%), Navicula (64.2%) and Daphnia (71%) genera. Numerically, Cosmarium (38.5%) and Microsystis (31%) dominated the food of O. niloticus. However, Geometric Importance Index GII suggested that the most consumed group was Microcystis (83.93%). A monthly variation was also noted in the stomach contents of O. niloticus over the period of investigat...
Nile tilapia (Oreochromis niloticus L.) is indigenous species to Ethiopia and constitutes major p... more Nile tilapia (Oreochromis niloticus L.) is indigenous species to Ethiopia and constitutes major proportion in the country’s fish production. In an attempt to select better performing strains for aquaculture development, tilapia populations from different Ethiopian rift valley lakes showed different growth performances in pond culture. Investigation of desired culture characteristics of target tilapia populations is required to improve their productivity in aquaculture system. The current study was made to investigate phenotypic characters of the tilapia populations in three geographically isolated Ethiopian rift valley lakes (Chamo, Koka and Ziway). A total of 450 adult tilapias of commercial catches were sampled from the three lakes and their phenotypic characters were analyzed during May 2018 to March 2019. Twenty six morphometric character indices, eight meristic counts, total length, standard length, total weight, length-weight relationship and Fulton’s condition factor were con...
The freshwaters of the East African nation of Ethiopia are divided into nine main drainage basins... more The freshwaters of the East African nation of Ethiopia are divided into nine main drainage basins. One of these, the Omo-Turkana basin, spans a large part of southwestern Ethiopian highlands and northern Kenya, and consists of the Omo-Gibe (or simply, Omo) River and a northern portion of Lake Turkana. Despite some development activities, including proposed dam construction with potential impacts on ichthyofaunal diversity, the Ethiopian part of the basin generally lacks comprehensive study or full scientific documentation. During the current surveys 31 species were identified from the lower Omo River and Ethiopian part of Lake Turkana, with some new records for the basin. The Omo River system was found to be richer in species while Lake Turkana has a higher abundance. Ichthyofaunal diversity within Ethiopian waters is specifically addressed, and an annotated checklist for native species of the basin is provided.
International Journal of Fisheries and Aquatic Studies, 2015
The reproductive biology of dominant fish species below the Tisisat Fall of Blue Nile River was s... more The reproductive biology of dominant fish species below the Tisisat Fall of Blue Nile River was studied during the wet season (September-October, 2010) and dry season (March-April, 2011) using gillnets of stretched mesh size 6, 8, 10 and 12cm, monofilaments of different mesh size, castanet and hook and line. A biotic parameters, temperature, transparency, conductivity, pH and total dissolved solid of the river were taken. A total of 857 fish specimens were collected with the two sampling seasons from all sampling sites. Out of the total catch of specimens four dominant fish species was contributed 79 %. The length weight relationship of L. intermedius, L. forskalii and M. kannume were curvilinear and the relation was statistically significant (P 0.05) in both season and sex however, L. forskalii was statically significant (P< 0.01) in seasons only. Except L. nedgia M. kannume, C. gariepinus and O. niloticus species were collected from the Blue Nile river were significant differen...
Six sampling sites of Gilgel Abay River and its tributaries,were sampled by using monofilaments (... more Six sampling sites of Gilgel Abay River and its tributaries,were sampled by using monofilaments (5-55 mm) and gillnets having meshsizes of 6, 8, 10, 12 and 14 cm stretched bar mesh with a length of 25 m and depth of 1.5 m, twice each month from August to October, and once inNovember, 2011. Fishes were identified to the species level. Fork length (FL), total weight (TW) and gonad weight (GW) of each specimen weremeasured. The relationship between FL and TW for the dominant species of Labeobarbus showed curvilinear relationship. Condition factor of L.intermedius, L. brevicephalus and L. nedgia showed that there was significant difference (p<0.001) between sexes in all three species. In all catch, females were more numerous than males. The highest GSI (15.54%) was recorded for L. brevicephalus but the maximum mean monthly GSI (7.01%) was recorded for L. longissimus in September and minimum GSI (0.45%) for L. macrophtalmus in August. Absolute fecundity, mean fecundity and mean FL for...
This study was conducted to evaluate the effects of different inclusion levels of water hyacinth ... more This study was conducted to evaluate the effects of different inclusion levels of water hyacinth leaf meal fermented with Aspergillus niger on feed utilization efficiency and growth performance of Nile tilapia (Oreochromis Niloticus L.). Fermented water hyacinth leaf (FWHL) at 0, 10, 20 and 30% inclusion levels were incorporated into four isonitrogenous (35% CP), and isoenergetic (18 KJ g-1 g) test diets. The fishes were stocked in 80 liters aquarium units, in a closed, recirculating indoor system. The diets were fed to triplicate groups of fish fingerlings (1.6 g average body weight) twice a day, at 6% of body weight/day, for three months. The study demonstrated that Nile tilapia fed FWHL at levels 30% had a significant negative impact (P<0.05) on weight gain, specific growth rate, feed utilization efficiency, and whole body composition. But, there were no significant changes between diets supplemented with 10% and 20% FWHL when compared with the control group. Therefore, supple...
This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Eth... more This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Ethiopia, with emphasis on potential spatial, size and seasonal effects on ingested food items. This study of the food and feeding biology of O. niloticus in Lake Langeno, Ethiopia, was conducted from March 2016to February 2017. Fish samples were collected monthly from six different sampling sites using different mesh sizes of gillnets. A total of 610 fish specimens with full stomachs were considered for the assessment of feeding biology. In total, seven food items, namely phytoplankton, zooplankton, insects, detritus, macrophytes, fish parts and nematodes, were identified from the fish stomach contents. Phytoplankton was the most commonly consumed food prey, followed by detritus, zooplankton and macrophytes. The other food items were occasionally and randomly consumed. Phytoplankton and detritus were the dominant food prey in the dry season, with zooplankton and macrophytes the main prey d...
International Journal of Sciences: Basic and Applied Research, 2017
This experiment was conducted to explore the effects of chemical and organic fertilizers at diffe... more This experiment was conducted to explore the effects of chemical and organic fertilizers at different levels of stocking density on the growth performance and yield of Nile Tilapia (Oreochromis niloticus (Linnaeus, 1758)) in earthen pond culture in southwestern Ethiopian highland located at an altitude of 1700 m above sea level. The ponds were divided into control and treatment with diammonium phosphate (DAP) and poultry manure application at three levels of stocking densities as 1, 2 and 3 fish m in a completely randomized design. All the experimental ponds had two replicates. The fertilizers were applied to the treatment ponds at a rate of 2 g m per week for 150 days. Juveniles with mean initial weight of 20.9 ± 0.19 g and mean initial length of 11.51 ± 0.16 cm were stocked. -----------------------------------------------------------------------* Corresponding author. International Journal of Sciences: Basic and Applied Research (IJSBAR) (2017) Volume 32, No 2, pp 80-94 81 The res...
International journal of ecology and environmental sciences, 2015
We investigated the food and feeding habits of Nile tilapia, Oreochromis niloticus, in Lake Hayq,... more We investigated the food and feeding habits of Nile tilapia, Oreochromis niloticus, in Lake Hayq, Ethiopia from August 2008 to March 2009. A total 931 fish were collected by gillnets of various stretched mesh sizes, of which 326 individuals of Oreochromis niloticus stomachs contained food. The stomach contents were analyzed using frequency of occurrence, numerical methods and the Geometric Index of Importance (GII). The food items in the stomach covered a wide variety, ranging from various types of phytoplankton to zooplankton and to macrophytes. The major food items in terms of frequency of occurrence were Microcystis (87.7%), Cosmarium (65.13%), Navicula (64.2%) and Daphnia (71%) genera. Numerically, Cosmarium (38.5%) and Microsystis (31%) dominated the food of O. niloticus. However, Geometric Importance Index GII suggested that the most consumed group was Microcystis (83.93%). A monthly variation was also noted in the stomach contents of O. niloticus over the period of investigat...
Nile tilapia (Oreochromis niloticus L.) is indigenous species to Ethiopia and constitutes major p... more Nile tilapia (Oreochromis niloticus L.) is indigenous species to Ethiopia and constitutes major proportion in the country’s fish production. In an attempt to select better performing strains for aquaculture development, tilapia populations from different Ethiopian rift valley lakes showed different growth performances in pond culture. Investigation of desired culture characteristics of target tilapia populations is required to improve their productivity in aquaculture system. The current study was made to investigate phenotypic characters of the tilapia populations in three geographically isolated Ethiopian rift valley lakes (Chamo, Koka and Ziway). A total of 450 adult tilapias of commercial catches were sampled from the three lakes and their phenotypic characters were analyzed during May 2018 to March 2019. Twenty six morphometric character indices, eight meristic counts, total length, standard length, total weight, length-weight relationship and Fulton’s condition factor were con...
The freshwaters of the East African nation of Ethiopia are divided into nine main drainage basins... more The freshwaters of the East African nation of Ethiopia are divided into nine main drainage basins. One of these, the Omo-Turkana basin, spans a large part of southwestern Ethiopian highlands and northern Kenya, and consists of the Omo-Gibe (or simply, Omo) River and a northern portion of Lake Turkana. Despite some development activities, including proposed dam construction with potential impacts on ichthyofaunal diversity, the Ethiopian part of the basin generally lacks comprehensive study or full scientific documentation. During the current surveys 31 species were identified from the lower Omo River and Ethiopian part of Lake Turkana, with some new records for the basin. The Omo River system was found to be richer in species while Lake Turkana has a higher abundance. Ichthyofaunal diversity within Ethiopian waters is specifically addressed, and an annotated checklist for native species of the basin is provided.
International Journal of Fisheries and Aquatic Studies, 2015
The reproductive biology of dominant fish species below the Tisisat Fall of Blue Nile River was s... more The reproductive biology of dominant fish species below the Tisisat Fall of Blue Nile River was studied during the wet season (September-October, 2010) and dry season (March-April, 2011) using gillnets of stretched mesh size 6, 8, 10 and 12cm, monofilaments of different mesh size, castanet and hook and line. A biotic parameters, temperature, transparency, conductivity, pH and total dissolved solid of the river were taken. A total of 857 fish specimens were collected with the two sampling seasons from all sampling sites. Out of the total catch of specimens four dominant fish species was contributed 79 %. The length weight relationship of L. intermedius, L. forskalii and M. kannume were curvilinear and the relation was statistically significant (P 0.05) in both season and sex however, L. forskalii was statically significant (P< 0.01) in seasons only. Except L. nedgia M. kannume, C. gariepinus and O. niloticus species were collected from the Blue Nile river were significant differen...
Six sampling sites of Gilgel Abay River and its tributaries,were sampled by using monofilaments (... more Six sampling sites of Gilgel Abay River and its tributaries,were sampled by using monofilaments (5-55 mm) and gillnets having meshsizes of 6, 8, 10, 12 and 14 cm stretched bar mesh with a length of 25 m and depth of 1.5 m, twice each month from August to October, and once inNovember, 2011. Fishes were identified to the species level. Fork length (FL), total weight (TW) and gonad weight (GW) of each specimen weremeasured. The relationship between FL and TW for the dominant species of Labeobarbus showed curvilinear relationship. Condition factor of L.intermedius, L. brevicephalus and L. nedgia showed that there was significant difference (p<0.001) between sexes in all three species. In all catch, females were more numerous than males. The highest GSI (15.54%) was recorded for L. brevicephalus but the maximum mean monthly GSI (7.01%) was recorded for L. longissimus in September and minimum GSI (0.45%) for L. macrophtalmus in August. Absolute fecundity, mean fecundity and mean FL for...
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