Natugonza, ViannyOgutu-Ohwayoa, RichardMusinguzia, LabanKashindye, BenedictoJónsson, SteingrímurThor Valtysson, Hreidar2022-12-022022-12-022016Natugonza, V., Ogutu-Ohwayo, R., Musinguzi, L., Kashindye, B., Jónsson, S., & Valtysson, H. T. (2016). Exploring the structural and functional properties of the Lake Victoria food web, and the role of fisheries, using a mass balance model. Ecological modelling, 342, 161-174.https://www.sciencedirect.com/science/article/pii/S030438001630518Xhttps://nru.uncst.go.ug/handle/123456789/5672tHuman and environmental factors have greatly challenged Lake Victoria ecosystem, especially in the lastfour decades. However, the lake continues to support the World’s largest freshwater fishery, currentlyproducing ca. one million tons of fish per year and directly supporting livelihoods of ca. four millionpeople in three riparian countries. We used the Ecopath component of Ecopath with Ecosim modellingsoftware to re-parameterise two existing mass balance models to reflect ecosystem state of Winam Gulfin 1971–1972 and 1985–1986, and construct a new model for the whole lake to reflect ecosystem statein 2014. The aim was to understand the structural and functional properties of Lake Victoria food weband the role of fisheries on the ecosystem. We found a decrease over time in productivity in relationwith biomass and respiration, and food web connectivity, and an increase in biomass cycling. The totalsystem throughput, decreased fivefold between 1971 and 1972 and 1985–1986, but was slightly higherin 2014 with a moderate shift from herbivory to detritivory. The implication of these changes on systemmaturity and resilience are discussed. The trophic level of catches increased between 1971 and 1972and 1985–1986 due addition of high trophic level catches from the introduced piscivorous Nile perch(Lates niloticus) i.e. “fishing up”. However, the decline in trophic level of catches between 1985 and 1986and 2014 seems to have been due to sequential addition of low trophic level catches, especially fromthe native Silver cyprinid (Rastrineobola argentea), a phenomenon termed “fishing through”, as opposedto a decline of high trophic level catches (or “fishing down”). Currently, exploitation is unbalanced andskewed to the least productive species at higher trophic level, with significantly less fishing occurring atthe most productive species at lower trophic level, and the causes are discussed.enBalanced fishingEcopath with EcosimLake Victoria Massbalance ResilienceArticle