We present a GIS-based approach to the delineation of areas that have different levels of suitability for use as tilapia cage culture sites the Kenyan part of Lake Victoria, Africa. The study area was 4,100 km2 . The method uses high-resolution bathymetric dat a, newly collected water quality data from all major fishing grounds and cage culture sites, and existing spatial information from previous studies. The spatio -temporal (space and season) parameters considered are water depth, water temperature, levels of dissolved oxygen, chlorophyll- a concentrations, distances to the lake shoreline and proximity to other constraints on cage culture development. The results indicated that the area most suitable for fish cages comprised about 362 km2, or approximately 9% of the total area; the remaining 91% (i.e. 3,737 km2) was found to be unsuitable for tilapia cage culture (Figure 1) . We conclude that the successful implementation of this approach would need stakeholder involvement in the validation and approval of potential sites, and in the incorporation of lake zoning into spatial planning policy and the regulations that support sustainable use while minimising resource use conflicts. The results of this study have broader applicability to the whole
of Lake Victoria, and other Great Lakes in the world for tilapia cage culture.
Keywords: GIS, Lacustrine; cage culture; wild fisheries; spatial planning; sustainability.