Predictor variables for moggel (Labeo umbratus) biomass and production in small South African reservoirs

  • WM Potts Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
  • AJ Booth Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
  • T Hecht Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
  • TG Andrew Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa

Abstract

The biomass and production of moggel, Labeo umbratus, in five small previously unexploited Eastern Cape reservoirs were estimated and related to environmental conditions. Biomass and production estimates varied widely between the reservoirs. Whilst the production/biomass ratio was not a good indicator of fishery potential, conductivity, mean reservoir depth and surface area proved to be the most suitable predictors of moggel biomass and production, whereas chlorophyll a concentration was somewhat less suitable. Results suggested that reservoirs with high conductivity (>50mS.m–1), small area (<50ha) and shallow depth (<3m) would have the highest moggel biomass and production.

Keywords: age and growth, empirical modelling, moggel, small water bodies

African Journal of Aquatic Science 2006, 31(1): 107–117
Published
2006-08-01
Section
Articles

Journal Identifiers


eISSN: 1727-9364
print ISSN: 1608-5914