Clarias ngamensis Castelnau 1861

The Kwando River system is generally construed to consist of the upper Kwando originating in the Angolan headwaters, the middle reach Linyanti swamps and the lower reach Chobe River. The blunt-nosed African catfish (Clarias ngamensis) is a demersal species particularly prevalent in the swampy mid reaches of the river system, where heavily vegetated, shallow and slow moving flow regimes persist. Ion concentrations jgenerally in the rapid flowing river mainstem tends to be low in ionic content; however, swampy areas often contain higher concentrations of nitrate and other ionic components. Correspondingly, planktonic content is only appreciable at these slackwater portions of the river, notably in the Linyanti Swamp. The Kwando waters generally exhibit a lower pH level than the neighboring Okavango River, but have a slightly higher sulfate concentration. The largest native demersal fish species in the Kwando is the 117 centimeter (cm) long tiger fish (Hydrocynus vittatus). Other large demersal native species are the 70 cm Kafue pike (Hepsetus odoe), and the 50 cm western bottlenose mormyrid (Mormyrus lacerda} . Each of these demersal vertebrate species are assigned a high trophic level (in the vicinity of level four).