Enjoy our river mouths and protect them
Estuaries are some of the most popular recreation sites and offer a wealth of animal and plant life that needs to be protected from overexploitation.
The Eastern and Southern Cape boast a large number of estuarine systems, and of historical interest, the early seafarers and settlers in this region regarded them as sources of wealth.
Some of these Eastern Cape estuaries include those at Zwartkops, in Gqeberha, and in the Tsitsikamma region, while the Sundays River Estuary is narrow with steep banks and has virtually no salt marshes.
Permanent open estuaries are open to the sea and have between one to ten million cubic metres of water entering and leaving them daily. Most southern African estuaries were formed as a result of the inundation of river valleys by the sea, since, during the last 15,000 years the sea levels have a moderate tidal prism the amount of water entering and leaving the estuary over a full spring tide.
There is usually a wetland area in the permanently open estuaries which, in the Eastern Cape are usually salt marshes and, in the former Transkei, mangroves. Salinities in the permanently open estuaries may fluctuate.
Some temporarily open estuaries are linked to estuarine lakes and as a result, their behaviour is closely linked to water level fluctuations in these lakes, since a rise in the lake level due to incoming fresh water may exceed the evaporation and lead to a rise in water levels in the adjacent temporarily closed estuary.
Estuarine plants include seaweeds, for instance, Caulerpafiliformis, which are essentially marine plants, and a variety of submerged aquatic flowering plants such as eelgrass (zosteracapensis).
Bird species found in Eastern Cape estuaries include waders, kingfishers, cormorants, gulls, tern, and even larger birds such egrets and herons.
Terrestrial mammals include the black-backed jackal, caracal, Cape clawless otter and the large-spotted genet.
Herbivores include steenbuck, oribi and bushbuck.