The water quality of almost all of South Africa's river systems has worsened progressively as a result of increasing urbanization and industrialization; the adverse effects of poor water quality have been compounded by the operation of water storage reservoirs and abstraction of increased volumes of water for human uses (Ashton, 2007). This has resulted in a progressive - and sometimes dramatic - reduction in the numbers and abundance of several sensitive species of insects, amphibians, fish and aquatic mammals in the worst affected river systems (O'Keeffe et al., 1989; Darwall et al. 2009). More recently, public attention has been caught by the deaths of large numbers of Nile crocodiles (Crocodylus niloticus) at several points along the Olifants River, the largest of several rivers flowing through South Africa's renowned Kruger National Park (Steyn, 2008; Van Vuuren, 2009). Keywords: Aquatic conservation, Marine ecosystems, Freshwater ecosystems, Nile crocodiles, Olifants River, River systems.