Get access
Advertisement

River flow and fish abundance in a South African estuary

Authors

  • A. K. Whitfield,

    Corresponding author
    1. South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa and
      Author to whom correspondence should be addressed. Tel.: +27 46 603 5829; fax: +27 46 622 2403; email: a.whitfield@ru.ac.za
    Search for more papers by this author
  • T. D. Harrison

    1. Council for Scientific and Industrial Research, P. O. Box 17001, Congella 4013, South Africa
    Search for more papers by this author

Author to whom correspondence should be addressed. Tel.: +27 46 603 5829; fax: +27 46 622 2403; email: a.whitfield@ru.ac.za

Abstract

The ichthyofauna of the Thukela Estuary, a small (55 ha), shallow (<1·5 m) system on the KwaZulu-Natal coast (mean annual river runoff of 3865 × 106 m3, from a large catchment of 29 000 km2, is seasonal: peak inputs occurring between November and March), was dominated by the juveniles of marine taxa that used the estuary as a nursery area. A striking feature of the above community was the decline in fish abundance with increasing river input, with flow values >100 m3 s−1 leading to increased loss of species from the system. This decline was linked to the lack of saline intrusion into the estuary and increased freshwater flooding through the system.

Get access to the full text of this article

Ancillary