From South African National Parks website:

The Langebaan Lagoon was proclaimed as a marine reserve in terms of the Sea Fisheries Act in 1973 and later in 1985, was proclaimed Langebaan National Park with the name later being changed to West Coast National Park.  It was on 25 April 1988 that the Langebaan Ramsar site was declared.

In the South African Context, the saltmarshes of Langebaan are unique in that no river feeds into the lagoon. These salt marshes constitute approximately 32% of the entire saltmarsh habitat in the country, the largest in South Africa. The lagoon is entirely marine with a relatively stable salinity and supports dense populations of molluscs and crustaceans as well as 71 species of different marine algae. The lagoon also serves as a nursery for the development of juvenile fish; the extensive intertidal areas of the lagoon support up to 55 000 water birds in summer, most of which are waders (23 species), including 15 regular Palaearctic migrants.

http://www.sanparks.org/parks/west_coast/images/maps/map2.jpg

More Information:

Zone B still Zoned Out for Langebaan Fishers (16 June 2014)