The Kosi Bay System, a complex of six large lakes, two lesser lakes and an estuary and is undoubtedly the best-preserved large estuary along South Africa's Indian Ocean coastline. It is little degraded and supports a great diversity of fish and other aquatic fauna. The system is characterized by undulating grassland interspersed with lakes, pans, streams, marshes and swamps. Primary vegetation communities include marshes, sedge and aquatic communities, swamp forests, mangroves, coastal dune forests, open woodland and palm communities. Many of these communities house numerous rare plant species. The swamp forests found in this area are the largest in the country. The giant palm Raphia australis, on which the palmnut vulture Gypohierax angolensis is dependent, finds its natural southern limit here. This is the only area in South Africa where five species of mangrove, including the species Luminitzera racemosa and Ceriops tagal are found. Kosi Bay supports a great variety of fish and other aquatic fauna. It probably provides the only recruitment for several species of marine fish found along the KwaZulu-Natal coast. There are eight known Red Data fish species in the area, most of which have their largest known populations in the Kosi System. There are always small numbers of greater flamingoes Phoenicopterus ruber and lesser flamingoes P. minor and ospreys Pandion haliaetus are regularly seen. Several bird species at Kosi are also at the most southerly limits of their distribution and are not encountered elsewhere in South Africa. As well as being largely dependent on the surrounding flora, the rural people in the area use traditional fishing methods to harvest the numerous fish species in the estuary. This provides an important protein source to local families and a tourist attraction to Kosi Bay's many visitors. The utilization of resources from the system, and its regulation by the authorities, provides an excellent example of the concept of wise use in action.