Development and application of a fish-based Sensitivity-weighted Index of Biotic Integrity (SIBI) for use in the assessment of biotic integrity in the Klip River, Gauteng, South Africa

  • P J Kotze Department of Zoology, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa
  • G J Steyn Department of Zoology, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa
  • H H du Preez Department of Zoology, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa<br>Rand Water, Hydrobiology Section, Vereeniging 1939, South Africa
  • C J Kleynhans Department of Zoology, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa<br>Resource Quality Services, Department of Water Affairs and Forestry, Private Bag X313, Pretoria 0001, South Africa
Keywords: bio-monitoring, biotic integrity, Fish Assemblage

Abstract

Biotic indices using fish assemblage characteristics have been applied with great success in river assessments around the world. Internationally the most commonly applied fish index is the Index of Biotic Integrity (IBI), whilst in South Africa the most commonly applied index is the Fish Assemblage Integrity Index (FAII). The Sensitivity-weighted Index of Biotic Integrity (SIBI) was developed as an alternative multimetric fish index, incorporating important principles from both the IBI and FAII. This study indicated that the SIBI was a valuable index which used fish as indicators of biotic integrity in the Klip River. The SIBI was also suited to the analysis of site-specific data and the investigation of specific impacts. It is envisaged that the SIBI concept could be applied to other aquatic systems and could possibly be used as an alternative fish index for South African rivers, especially when investigations necessitate site-specific evaluations. The application of the SIBI and IBI in this study also emphasised the FAII\'s potential underestimation of biotic integrity. The results obtained from the use of the SIBI indicated that the biotic integrity of the Klip River System is currently moderately to critically modified from its natural condition.

African Journal of Aquatic Science 2004, 29(2): 129–143
Published
2005-03-01
Section
Articles

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eISSN: 1727-9364
print ISSN: 1608-5914