Browsing by Author "Constantine Chobet Ondhoro"

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Exploring the morphological dynamics of Nile tilapia (Oreochromis niloticus Linn. 1758) in Victoria Nile as depicted from geometric morphometrics
(BMC Zoology, 2023-11-23) Papius Dias Tibihika; Manuel Curto; Harald Meimberg; Cassius Aruho; George Muganga; Jerome Sebadduka Lugumira; Victoria Tibenda Namulawa; Margaret Aanyu; Richard Ddungu; Constantine Chobet Ondhoro; Tom Okurut
Background Various anthropogenic activities continue to threaten the fish biodiversity of the East African water bodies such as the Victoria Nile. Although the Victoria Nile is a significant source of livelihood for human populations, the biology and ecology of Nile tilapia in this ecosystem remain understudied with little or no information on the morphology of the fish given varying and immense anthropogenic activities. Here, we use geometric morphometrics to examine the morphology/shape variations of Nile tilapia populations in Victoria Nile to gain insights into their current ecological state. Results Our results indicate unexpectedly smaller Nile tilapia body weights in Victoria Nile than in L. Victoria. Despite this, nearly all the populations displayed a relative condition factor (Kn) of greater ≥1 suggesting a healthy stock. How- ever, two populations, LMF and VN_Bukeeka demonstrated Kn values of less than one (< 1). We also report that some Upper and Lower Victoria Nile populations display morphological similarities. Apart from L. Albert, Nile tilapia populations from Lakes Victoria and Kyoga are morphologically divergent from the riverine ones. We note that Nile tilapia from Nalubale Dam Reservoir is morphologically distinct from the close neighbouring Victoria Nile populations which are likely allied to the influence of the Nalubale Hydroelectric power dam as a barrier. Conclusion Nile tilapia’s morphological variation appears to be influenced by various anthropogenic disturbances notably, over fishing, hydroelectric power dams, and fish translocational history in Uganda. Management should enforce regulatory frameworks to avert human-mediated activities as these are likely to compromise the sustainability of the sheries. Further studies are required to follow these populations with molecular genetics and environmental data to gain a deeper understanding of the sh species for informed sustainable management and conservation options.
Growth and Economic Evaluation of Different Fish Species for Culture in Uganda’s Mid Altitude Areas Using Local Feeds
(Journal of Applied Sciences, 2023-03-02) Constantine Chobet Ondhoro; Ismail Kagolola; Gerald Osipa; Robinson Odong; Godfrey Kawooya Kubiriza; Lawrence Owere
Background and Objective: The East African high-altitude areas remain ecologically challenging to tropical native farmed fish species, the Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) yet the potential for cold-water fish culture is as well unexploited. This study describes the effects of environmental quality and local feed on the growth and economic performance of selected fish species for 5 months along the slopes of Mountain Elgon Uganda. Materials and Methods: Three earthen ponds each 200 m3 by volume were conditioned with hydrated lime at 0.1 kg mG3 for a week. The ponds were stocked with juveniles of Rainbow trout (Oncorhynchus mykiss), Nile tilapia and Mirror carp, averaging 1.5±0.1, 17.9±2.2 and 2.0±0.2 g (±SE), respectively. The fish were fed to satiation daily on 35% C.P local feed for 5 months. Water quality and growth data were collected daily and monthly, respectively. Performance parameters were computed and analyzed using univariate ANOVA and regression analysis in SPSS20. Results: There was a highly significant difference (p<0.001) in mean body weight gain (g/day) between Rainbow trout and the Nile tilapia (mean diff 0.0788, p<0.001) and Mirror carp (mean diff 0.087, p<0.001) and between Rainbow trout and the two species combined (mean diff 0.016, p = 0.006). The highest weight gain (4.8 g/day) overall was demonstrated by Mirror carp in the 4th month of growth. The mean relative condition (Kn) for respective species (p<0.05) were all <1. The Mirror carp was the most profitable, at Ugshs 4, 130, 463 (44.9%) of total revenue, while trout incurred over 92.1% (Ugshs -3, 974, 994.5) losses. Mirror carp demonstrated better economic viability with the experimental feed in the area, however, this can be much better with improved management. Conclusion: The observed growth patterns were consistent with temperature variation and feed quality, thus, Nile tilapia performed poorly due to low water temperature and Rainbow trout was worse due to poor feed quality that negatively influenced visibility and feed intake.