Browsing by Author "Tenywa Mwanja, Matthew"

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    Escape of farmed tilapiines into the wild and entry of wild forms in fishponds, and the possible interactions between wild and farmed tilapiines from a sample of smallholder farms in Central Uganda
    (African Journal of Ecology, 2009) Tenywa Mwanja, Matthew; Waiswa Mwanja, Wilson
    Seven smallholder fishponds in central Uganda were studied between 2000 and 2001 to investigate the interaction of farmed tilapiines with their wild conspecifics. Emphasis was on the features that facilitate escape of fish and ⁄ or entry of fish into the farms and interactions between the farmed and the wild. These included number of species, source of seed, connection between pond and natural watercourses, purpose of the farm, destination of cultured fish and interaction between farmed and wild fish. Fishponds had no screens against entry of wild fish into the farm or escape of farmed fish into the wild and occurred within wetlands close to natural watercourses. Ponds stocked with one fish species were found to have multispecies with some individuals that were apparently intermediate morphs between the species. Fry produced within the growout fishponds was shared with other farmers within and outside the watersheds. This study showed that smallholder farms with little or no control of escape or entry of fish out and into the fishponds, and little or no management present circumstances that facilitate continued movement of tilapiines within and across watersheds in Ugandan waters. The study also indicated possible genetic interaction between farmed and their wild conspecifics through interactions within fishponds.
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    Preliminary results of the analysis of the population structure of the Nile perch (Lates niloticus linnaeus, 1758) of Lake Victoria using microsatellite markers
    (African Journal of Biotechnology, 2008) Tenywa Mwanja, Matthew; Waiswa Mwanja, Wilson
    Preliminary results are provided of a study instituted to analyze the genetic population structure of the Nile perch in Lake Victoria since 2002. 293 individuals from six geographically distinct locations within the lake were analyzed using two polymorphic microsatellite DNA markers. Tests for differentiation with an overall FST = 0.03 (P < 0.05) suggested that populations were genetically differentiated, with the closet population pairs Nyaburu-Rubafu and Mirunda-Maboko as the most differentiated populations. There was an extensive gene flow between the populations (Nm = 20.77). The overall gene diversity (0.17) was low. All the results point to the fact that Nile perch was only recently introduced species in the lake based on a small founder population, which though slow in establishing later exploded to become the most dominant species in the lake. On the whole the two loci indicate some level of differentiation between locations; however, the levels of genetic differentiation shown by the two loci were not enough to define the structure of Nile perch stocks, and assess the level of exchange between locations. Further work is underway using bigger number of microsatellite markers.
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    Socio-economic considerations for rural aquaculture development of Singida tilapia, Oreochromis esculentus (Teleostei: Cichlidae, Graham 1928) in Uganda, East Africa
    (International Journal For Research In Applied And Natural Science, 2018) Banga, Margaret; Kudeeba Mwanja, Richard; Namumbya, Sarah; Owani, Simon-Olok; Nadiope, Eric; Tenywa Mwanja, Matthew; Mwanja, Waiswa Wilson
    Domestication and development of aquaculture of Singida tilapia (Oreochromis esculentus) is being promoted in Uganda as a means of conservation of the species threatened with extinction but also as a means of promoting improved supply of fish to poor communities living in remote fishing communities that cannot afford commercial feeds based aquaculture of current farmed fish species in Uganda. The cost of fish feeds is a big deterrent to rural aquaculture development. Singida tilapia predominantly herbivorous nature coupled with other attributes makes this species a prime candidate for rural aquaculture development. As such a socioeconomic was conducted to assess Singida tilapia suitability for rural aquaculture development between July 2014 and June 2016 as part of the national effort to conserve and restore this previous fisheries highlight as a key fish source for rural Uganda. Knowledge and experience in use of such a species, need to lure rural women and youth in aquaculture, and need for a low input system were assessed against the attributes of Singida tilapia including handling under pond conditions, use of natural feeds, simple hatchery system/processes, and appreciable growth performance under pond culture conditions. Singida tilapia was assessed to fit the rural farmers’ cited attributes for its rural aquaculture development.