Whole body and egg amino acid composition of Nile perch, Lates niloticus (Linnaeus, 1758) and prediction of its dietary essential amino acid requirements

Eggs and tissue of Nile perch juveniles were analysed in order to derive the essential amino acid dietary requirements for Nile perch larvae and juveniles, using the A/E ratio. Results revealed the presence of both essential and non-essential amino acids in Nile perch. A significant difference (p < 0.05) between the amino acids (AA) composition in the eggs and tissue and amongst the four class sizes of juveniles was observed. Estimates of the amino acid dietary requirements revealed that Nile perch has high arginine, leucine, threonine, valine and isoleucine dietary requirements.Key words: Nile perch, amino acids, dietary requirements, larvae, juveniles

Reproductive biology of ningu, Labeo victorianus (pisces: cyprinidae), in the kagera and Sio rivers, Uganda

We investigated aspects of the reproductive biology of the cyprinid fish, Labeo victorianus, locally known as ningu, in the Kagera and Sio Rivers, Uganda. These rivers represent the last remaining refuges for this species within Uganda. L. victorianus is a highly fecund, potamodrometic fish that migrates upstream to spawn. Spawning is generally synchronised with the bimodal water level maxima observed within the rivers. There were, however, some deviations from this pattern. We caught sexually mature fish throughout the year in the Sio River, and noticed that spawing started before the second rainfall peak. Fish from the Kagera matured at significantly larger sizes than fish from the Sio River. Male and female fish, from both rivers, fed intensively during the non-breeding months accumulating significant fat reserves; a probable energy storage mechanism prior to their spawning migrations. The differences between the populations is probably a phenotypic response to differing abiotic factors such as river size, flow velocity and food availability

An overview of domestication potential of Barbus altianalis (Boulenger, 1900) in Uganda

Domestication of fish is a key strategy for diversification of farmed species to meet consumer’s choices and demands as well as conservation of the species for sustainable provision of nutrition benefits and incomes. Initial successful induced spawning of Barbus altianalis was achieved, but there is low adoption attributed to lack of sufficient quality seed. This paper reviews the ecological and social-economic trends, and potential prospects that justify the domestication of this high value indigenous species, and identify gaps that could be addressed to increase seed production for commercialization. Review findings show that due to overexploitation, there is a steady decline of B. altianalis in Ugandan water bodies, with no current record from Lake Victoria where catches had in the past been reported. B. altianalis shows ability to survive in interlacustrine-riverine environments although, the juveniles are largely confined in the river or stream water. Varying levels of adaptability and tolerance to environmental conditions including oxygen and temperature by different age groups occur. The species has a great potential for culture as an omnivorous species with high chances of adapting to varying feeding strategies. Knowledge gaps in size at maturity, appropriate inducing hormones, growth conditions, egg hatchability and larvae weaning were identified as key challenges associated with B. altianalis domestication. Understanding the underlying natural ecological dynamics of B. altianalis will guide further research in the areas mentioned to ensure advancement in domestication so as to meet the rising demand for B. altianalis. This will curtail its overexploitation in the wild and also improve the livelihoods of the communities in the region. Keywords: Cyprinid, Omnivorous, Indigenous species, Domestication, Commercializatio

Aquaculture for increased fish production in East Africa

Fish is produced for human consumption and other purposes through capture fisheries and aquaculture. Fish production from natural stocks has already reached its limits and is declining while aquaculture production is increasing. Aquaculture is making a significant contribution to fish production in several countries thus proving to be a potential alternative to supplement the declining capture fisheries. In East Africa the contribution of aquaculture to the total fish production is still insignificant although it has been practised in the region since the 1900s. The predominant aquaculture production system in East Africa at present is small scale earthen ponds characterised by low inputs and low yields. Important ingredients for the emergence of a commercial aquaculture industry are highlighted with emphasis on the need for a conducive and harmonised policy framework across the region. This paper advocates a focused plan of action for aquaculture development in the region and makes succinct recommendations for fast transformation of the industry.Key words: Aquaculture, East Africa, Lake Victoria basin, production, marketing, regulation, new technologie