Lake Victoria, Africa’s largest lake and the second largest freshwater lake in the world, has undergone major environmental changes over the last century. An increase in fishing pressure, the introduction of exotic species and an increasing human pollution have all contributed to the degradation of the lake’s unique habitats and biodiversity (1) (6).
Commercial fishing began to increase from the 1930s, and by the 1960s most stocks of native fish in Lake Victoria had been greatly depleted. This led to the introduction of numerous exotic fish species, including the Nile perch which now dominates the lake, to increase the number of species available to commercial fisheries. However, many of these introduced species preyed upon native fish, contributing to one of the greatest modern extinctions of vertebrate species, with some 200 endemic cichlid species becoming extinct (1) (6).
The increasing human population around the shores of Lake Victoria is also contributing to the degradation of the waters. Over the last 20 years in particular, agriculture and urbanisation has intensified, leading to an increase in pollution of the lake, as untreated sewage often pours directly into the water. Textile and leather tanning factories, as well as breweries and paper mills, have also recently been developed along the lake’s shoreline, putting further pressure on the delicate ecosystem. As a result of this pollution, the oxygen content of many lake habitats is so low that they are now deemed uninhabitable for wildlife. The increase in commercial fisheries has also caused an increase in deforestation along the shoreline, as trees are felled to provide wood to smoke the fish before being traded, eventually leading to sedimentation and eutrophication (1) (6).