Kosi Bay System Designated 28 June 1991

The Kosi Bay System, a complex of six large lakes, two lesser lakes and an estuary, 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 hose 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 nearly 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.