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Fish conservation in South African estuaries
Author(s) -
WHITFIELD A. K.
Publication year - 1997
Publication title -
aquatic conservation: marine and freshwater ecosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 77
eISSN - 1099-0755
pISSN - 1052-7613
DOI - 10.1002/(sici)1099-0755(199703)7:1<1::aid-aqc213>3.0.co;2-8
Subject(s) - overfishing , overexploitation , threatened species , ecology , fishery , estuary , habitat , habitat destruction , geography , fishing , biology
1. Habitat degradation, mainly through land use changes and excessive freshwater abstraction, has a major negative effect on southern African estuarine systems. Less important at present, but showing increasing signs towards becoming a major problem is environmental pollution, especially organic and inorganic wastes from industrial, agricultural and domestic sources. Although the major threats to estuarine‐associated fishes are usually linked to environmental degradation, there is also evidence to suggest that certain fish species are declining in abundance primarily as a result of overfishing. 2. The viability of estuaries as nurseries and feeding grounds for fishes is directly related to the accessibility and productivity of these systems. Examples of the mismanagement of South African estuaries through excessive siltation, freshwater deprivation, poorly planned dredging activities, and artificial manipulation of estuary mouths, are discussed. 3. The need for conservation legislation based on a sound knowledge of the biology and ecology of threatened fish species, their communities and their habits is highlighted. Examples of possible ‘indicator’, ‘keystone’, ‘umbrella’ and ‘flagship’ species for South African estuaries are given. 4. Although estuaries on the subcontinent have long been recognized as nursery areas for a number of recreationally important marine fish species, these systems have not formed an integral component in the selection of marine reserves. The dependence of many marine teleosts on estuarine habitats necessitates the inclusion of these ecosystems in any aquatic reserve planning exercise. 5. The plight of endemic fish species is discussed, with the effects of both environmental degradation and overexploitation being highlighted. 6. It is concluded that the future health of South Africa's estuaries and their fishes depends on imaginative resource management and on the improved implementation of conservation measures in partnership with decision‐makers, managers, scientists and estuarine users. © 1997 John Wiley & Sons, Ltd.