ABSTRACT
There have been distinctive changes in the physical structure of Lake Victoria over the last 40 years associated with climate change, eutrophication, introductions of exotic species, and poor watershed management. More than 100 stations were sampled between 1990 and 1992 to assess the temperature, dissolved oxygen, winds and currents structure on the Kenyan area of Lake Victoria. The lake was stratified between September and May and mixing occured between June and August. This mixing was not sufficient to bring saturated oxygen levels from the surface to the bottom. Oxygen levels were very low below a depth of 40 m and were associated with extensive fish kills.
Current speeds usually were between 0.3 cm/s and 56.5 cm/s with a maximum of 150 cm/s. The studied currents were vertically structured, weak and did not flow in any well developed pattern. Multiple inversions and reversals were observed that may be time dependent and related to local wind changes, internal seiches and solar radiation. Swift currents were observed at channel areas in the late afternoon. The dominant wind on the lake was towards the northeast in the afternoon and to the southwest in the mornings, and ranged in speed from 0.1 to 9.3 m/s.
