The KRUGER NATIONAL PARK is drained by mainly east flowing systems.
There are two main drainage systems : the LIMPOPO system and the INCOMATI system.
The perenial rivers being the Levuvhu, Mutale, Groot Letaba, Olifants, Sabie and the Crocodile Rivers, normally placid flowing streams during the dry season, the water normally relatively clear. During the rainy season the rivers are in full spate, often muddy and turbulent.
Seasonal rivers, those that only flow for a short while during the rainy season, normally incorporate a series of permanent and semi permanent pools along their length.
The differenent systems are made up as follows :
Levuvhu River - the perennial river with seasonal rivers being : Matukwane, Madziringwe, Mashikiri and Mutale.
Shingwedzi River - the perennial river with seasonal rivers being: Dzombo, Shisha, Bubube, Phugwaqne and Mphongolo.
Groot Letaba River - the perennial river, with seasonal rivers being Shipikane, Hlanganini, Ngwenyeni, Makhadzi, Klein Letaba, Mbyashishi and Tsende.
Olifants River- the perennial river, with seasonal rivers being Bangu, Timbavati, Shisakashangondzo, Nhlarulume, Klaserie and Tsutsi.
The Incomati System
Nwanedzi River - the perennial river, with the seasonal rivers being Sweni, Mtomene and Gudzane.
Nwaswitsontso River - the perennial river, with the seasonal rivers being : Munweni, Nkuane and Vutome.
Sabie River - the perennial river, with the seasonal rivers being : Nwathimhiri, Nwashitshaka, Mtsawu, Mnonodzi, Sand, Mutlumubi and Nwatindlophu.
Crocodile River- the perennial river, with the seasonal rivers being : Nsikazi, Mtjulu, Mlambane, Mbyamiti, Bumi and Vurhami
Water temperatures depend on the ambient temperature and the volume and flowing speed, and also often form a thermal barrier being the cut off points for different species. The faster and deeper, the water flow, the relatively lower the water temperature. Water temperaures vary between 16 C and normally 33 C in exceptionally hot days.
pH levels is normally between 7,6 and 8,3 = alkaline during extremely dry periods the pH level could increase to 8,6.
The turbidity of the water affects the depth of sunlight penetration and has a great influence on the richness or poorness of the aquatic habitat - the distribution of the freshwater fishes. Very often fish swim up the tributaries to spawn, or to escape the muddy flood waters.
The heavily silt laden Levuvhu River is the legacy of erosion caused by poor farming practises upstream, support very fish fauna while the clearer pools in the seasonal tributaries again harbour a very rich and diverse aquatic fauna. The muddy waters of the Levuvhu offers ideal cover for the Crocodiles which contributes signifcantly to the depletion of the fish life.
The fishes of the KRUGER NATIONAL PARK feed the mentioned Crocodiles as well as the Fish Eagles, Kingfishers, Ospreys, Fishing Owls, Herons, Storks, Hamerkops, Darters and Cormorants as well as Otters, Monitors, Terrapins and Water Mongoose. These predators together with the periodic flooding and drying of the systems keep the fish fauna population in balance.
Habitat selection is also crucial to the survival of the species, some prefer rocky areas, others, sandy,others muddy, others clear, others coloured, others fast flowing, others, placid flowing, others pools - shallow or deep, or a combination of some of the above, or some just the vleis, flood plains and pans, to ensure survival and good health.
Many fish live for many years, often reaching maturity at the agre of eight to ten years, others are seasonal- the complete their lifecycle within one season.
The main threat to the survival of the Fishes of all the World, is pollution, caused by overpopulation and greed. Human and Industrial effluent is disposed of in the waters of our Rivers, introducing foreign conditions being acids, salts, enrichment. Catchment dams and weirs without fish ladders, disturb the migration of species, upsetting their breeding patterns and cycles.
I have spent much time parked on the Lower Sabie bridge watching the resident Mud Fish going about their day's business. Much time has also been spent by me and my wife at Nkuhlu watching the small shoals of Tilapia enjoying there freedom, and at Skukuza watching the fish lazily sunning themselves on a winters morning and at the bricge crossing the Shongololo watching the Barbel feeding on whatever being available, once we were fortunate enough to watch some small silvery, and blue tinged Tiger Fish with their red edged fins, hunting in the clear waters of the Crocodile River.
I participate because I care - CUSTOS NATURAE
Convenor of the AIKONA Group.
No to Hotels in and commercialization of our National Parks.
Done 142 visits to National Parks.
What a wonderful privilege.