Morphometric Variations of Nile Tilapia (Oreochromis niloticus) (Linnaeus, 1758) Local Strains Collected from Different Fish Farms in South Western Highland Agro-Ecological Zone (SWHAEZ), Uganda: Screening Strains for Aquaculture

Abstract

Despite the global contribution of aquaculture as an important pillar for food and nutritional security, its rapid growth has been hampered by inadequate and poor-quality seed due to inbreeding, hybridization of related stocks, and poor-quality broodstock. Phenotypic and genotypic characterization of Nile tilapia in natural water bodies of Uganda has been studied but research gaps remain on the morphometric characterization of farmed O. niloticus in Uganda, which hinders selective breeding initiatives. This study characterized O. niloticus from various farmers in Uganda’s Southwestern Highland Agro-Ecological Zone using their morphometric traits. In this study, 8 morphometric traits were taken on each of the 258 fish samples collected with at least 30 samples sampled from each pond system in the zone. The morphometric data generated were analyzed using multivariate analysis. In order to delineate the populations from the different ponds, Discriminant Function analysis (DFA) was performed on the dataset and distribution plots generated to test on the purity of the strains. There were significant differences in the morphometric traits among the populations with the Victoria fish population having the highest standard length while the Kyoga population had the highest weight. Morphometric characterization grouped the fish into three clusters, indicative that fish farms in the zone possibly had different sources of fish seed. The condition factor, which is a measure of wellbeing of the fish, showed that all the populations displayed an isometric growth which is indicative of the fish growing in length as it is in weight. The results of this study provide evidence that local O. niloticus from different farms display differences in body shape as a result of using fish seed from different sources. This aspect can be applied in selective breeding programs after establishing the genetic structure of the farmed Nile tilapia stock.

Comparative analysis of Oreochromis niloticus and a putative hybrid (Wesafu): A Search for morphometric identity

“…Even in O. niloticus from different populations significant morphological differences were detected across range of environmental gradients [25) due to genetic differentiations, food composition, depth, stocking density, farming method (pond or cage), habitats, and water quality [26,27]. Of all the morphometric traits examined in O. oreochromis 10 of them -SL, HD, HL, DFL, PFL, BDH, Pre-dorsal length, pre-ventral length, pre-pectoral length and dorsal spine length of the morphometric, variables showed low variability (CV˂ 10%) implying homogeneity in those characters.…”

Food Security of Region around Nyangezi in Eastern Congo and Lake Bunyonyi in Uganda

“…According to studies, the population around Lake Bunyonyi lives in relative food security (De Haan, 2016). Kwikiriza's (2016) study on Lake Bunyonyi highlights the potential for aquaculture in Uganda's lakes (notably Lake Bunyonyi). The study suggests that cage culture may be a suitable alternative for landless fish farmers.…”