Browsing by Author "Renalda N., Munubi"

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    Assessment of body size and catch per unit effort of Nile perch (Lates Niloticus) caught using different fishing gears at Magu district in Lake Victoria, Tanzania
    (African Science Publications, 2020-10-05) Renalda N., Munubi; Julitha N., Nyakibinda
    This study was conducted to assess body size distribution and Catch Per Unit Effort (CPUE) of Nile perch (Lates cf. niloticus) captured using three common fishing gears at Magu district in Tanzania. Three landing sites along Lake Victoria were selected for this assessment. Each site was visited twice per week for two months. At each site 10 boats were identified based on the gear used and randomly selected for fish count. Ten fish per boat were taken for weight and length measurements. The results show that the main fishing gears used to catch fish at all sites were gillnet (GN), long line (LL) and beach seine (BS). Mean length of captured fish recorded from each gear were 33.7, 41.5 and 43.8 for beach seine, gillnets and long lines respectively, which was below the minimal required length of 50 cm. Large proportion of small landed fish were observed in vessels fishing with beach seine, this was due to illegal nature of the beach seine, where by fishermen used small mesh sizes of 10 mm to 12 mm. However, beach seine had higher CPUE (kg/gear/day) (44.9) and gillnet had the lowest (22.6). This study revealed that the mean length from all sites were below the legal minimum size required by the Tanzanian government, suggesting that all beaches are involves in over exploration of fish.
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    Effects of fertilization and concentrate feeding on water quality and growth performance of Nile tilapia (Oreochromis niloticus) grown in concrete tanks
    (African Science Publications, 2020-10-05) Sebastian W., Chenyambuga; Renalda N., Munubi; Nazael A., Madalla; Kwamena, Quagrainie; Emmanuel, Frimpong; Hillary, Egna
    An experiment was conducted to compare the effects of fertilizer application alone, concentrate feeding alone and combination of fertilization and feeding on water quality parameters and growth performance of sex-reversed Nile tilapia (Oreochromis niloticus). Three treatments (weekly fertilization with urea and Diammonium Phosphate (DAP), concentrate feeding at 5% of fish body weight and weekly fertilization with urea and DAP plus concentrate feeding at 2.5% of fish body weight) were randomly allotted to nine concrete tanks. Three fingerlings per m2 were stocked in the tanks and grown for 166 days. Results indicated that treatment had significant effect (p ≤ 0.001) on water Dissolved Oxygen (DO), conductivity, total dissolved solids, nitrate and phosphorus but not on pH, salinity, temperature, ammonia and alkalinity. Fish cultured under the combination of feeding and fertilization had higher (p ≤ 0.0001) weight gain (257.37 ± 5.71 g), growth rate (1.50 ± 0.04 g/day), yield (13,128.35 kg/ha/year) and lower Feed Conversion Ratio (FCR) (1.89 ± 0.03) than those reared under feeding alone and fertilization alone. It is concluded that the combination of weekly fertilization and concentrate feeding at 2.5% of fish body weight is better than either weekly fertilization alone or feeding alone at 5% of fish body weight.