Potential for a commercial inland fishery or just another water storage facility at Spring Grove Dam, KwaZulu-Natal, South Africa?

Abstract

South Africa's inland fisheries are generally undervalued, though there is developing interest in the sector. Spring Grove Dam in the KwaZulu-Natal Midlands became operational as a water storage facility in 2013 to provide water to the growing urban population in the province. We assessed whether the impoundment could potentially support commercial fisheries as had been proposed during its design and construction. We conducted seasonal fish community surveys from 2020 to 2021 at sites along the impoundment and in the mainstem of the Mooi River which feeds into the impoundment. We recorded a total of nine fish species, including six non-native fishes with invasive characteristics. Only three of 10 expected native species were found, namely the KwaZulu-Natal yellowfish Labeobarbus natalensis, chubbyhead barb Enteromius anoplus and African longfin eel Anguilla mossambica. Catch per unit effort (CPUE) was low in the sampling surveys using mostly gillnets and fyke nets, and relatively low yields (14.97 tonnes yr-1) were subsequently calculated for the impoundment, making commercial fisheries unviable. However, the existing subsistence and recreational fisheries for non-native salmonids and the native L. natalensis would benefit by controlling the distribution range and abundances of non-native centrachids Micropterus spp. We offer recommendations and suggestions for management plans for Spring Grove Dam in the context of local fish diversity, a changing climate, further construction of water storage facilities on east-flowing rivers in the province, and a nationally neglected inland fishery industry.