Reviews in Fish Biology and Fisheries

, Volume 28, Issue 1, pp 19–31 | Cite as

Causes and consequences of human induced impacts on a ubiquitous estuary-dependent marine fish species

  • Alan K. Whitfield
  • Gareth N. Grant
  • Rhett H. Bennett
  • Paul D. Cowley


Decreasing populations of common estuary-associated marine fishes are being documented globally and red flags associated with such declines are often ignored due to the high relative abundance of these species when compared to more rare and threatened taxa. The Cape stumpnose Rhabdosargus holubi (Steindachner 1881) is an abundant and widespread southern African sparid that is dependent on estuaries as a primary nursery area. Historical and current information on the species is comprehensive and the accumulated evidence strongly suggests that this ubiquitous fish is under pressure, mainly due to degradation of estuaries and associated catchments, increasing fishing pressures from recreational and subsistence anglers, habitat loss relating to reduced submerged macrophyte areas in many systems, industrial and agricultural pollution, infrastructural developments in and around estuaries, and climate change. In particular, the temporary loss of Lake St Lucia, which accounts for approximately 50% of the estuarine surface area in South Africa, has drastically reduced the nursery area availability for R. holubi on the subcontinent. Overall we present strong evidence to support the hypothesis that present-day stocks of R. holubi are much smaller than those in the pristine state and that urgent management measures need to be considered and implemented to prevent current depleted populations of the species from declining further.


Estuarine degradation Global change Over-exploitation Population decline Rhabdosargus holubi Sparidae 



We thank the National Research Foundation (NRF) for funding that made this review possible.


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Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Alan K. Whitfield
    • 1
  • Gareth N. Grant
    • 1
    • 2
  • Rhett H. Bennett
    • 1
  • Paul D. Cowley
    • 1
  1. 1.South African Institute for Aquatic Biodiversity (SAIAB)GrahamstownSouth Africa
  2. 2.Department of Ichthyology and Fisheries Science (DIFS)Rhodes UniversityGrahamstownSouth Africa

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