Available information on macroinvertebrates of the Mhlathuze coastal lakes: setting the ecological reserve (lake water requirements)
This paper reviews current information on the macroinvertebrates of four coastal lakes in the Mhlathuze catchment of Zululand. The fauna are described in terms of the potential influence of lake level changes in response to increasing anthropogenic pressures for available potable and industrial water resources. The aim of the study was to provide background information to determine the Lake Water Requirements (LWR) for an ecological reserve study. Lakes Nsezi and Mangeza are drowned river valleys with muddy substrates and resident benthic populations indicative of their historically freshwater influences. Lakes Mzingazi and Cubhu are relict estuarine systems with faunal components and sediment characteristics reflecting this. All relict estuarine crustacea are now physiologically adapted to complete their life cycles within a closed freshwater system with no permanent connection to the sea. Few relict estuarine lake systems occur in southern Africa and their uniqueness must be a factor contributing to their conservation.