Browsing by Author "Papius Dias Tibihika"

Now showing 1 - 2 of 2

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.
Introgressive hybridization levels of Tilapiine species in Lake Victoria basin, Kenya inferred from microsatellite and mitochondrial DNA genotyping based on next-generation sequencing
(Conservation Genetics, 2023-09-27) Gerald Kwikiriza; Thapasya Vijayan; Papius Dias Tibihika; Manuel Curto; Gerold Winkler; Juliet Kigongo Nattabi; John Kariuki; Harald Meimberg
Despite their high abundance and species richness, tilapiines have been compromised by various factors especially over fishing, climate change, and uncontrolled sh transfers and introductions. Fish introductions have negatively impacted native tilapiine populations through competition, predation, hybridization, and introgression compromising their genetic integrity. The hybridization levels of different tilapiines in the Lake Victoria basin remain relatively understudied. The study utilized nuclear microsatellite and mitochondrial DNA (mtDNA) genetic markers to investigate hybridization signals and compare the genetic diversity of different tilapiines in Lake Victoria, Kenya, using next-generation sequencing. Low levels of hybridization from Oreochromis niloticus into other Oreochromis species were detected by Bayesian clustering analysis and principal coordinate analysis (PCoA). The results contribute to the need for conservation measures for these sh species.