Validation of growth zone deposition in otoliths of two large endemic cyprinids in Lake Gariep, South Africa

  • Henning Winker
  • Bruce R. Ellender
  • Olaf LF Weyl
  • Anthony J. Booth

Abstract

We tested the hypothesis that growth zones in the astericus otoliths of smallmouth yellowfish (Labeobarbus aeneus) and Orange River mudfish (Labeo capensis) were deposited annually. Two methods, fluorochrome marking and edge analysis of otoliths were used. For fluorochrome marking, specimens of both species were injected with 60 mg/kg fish mass oxytetracycline hydrochloride (OTC) and released into large earthen ponds under ambient conditions adjacent to Lake Gariep. Twenty-three L. aeneus and one L. capensis were recaptured 10–14 months later. Edge analysis was based on the optical interpretation of L. aeneus (n = 342) and L. capensis (n = 512) otolith margins collected between November 2006 and May 2008 from Lake Gariep. The frequency distribution of opaque margins over time was fitted using a binomial periodic regression. The estimated cycle length was not significantly different from a hypothesized 12 months for both species. The number of growth zones distal to the OTC mark was consistent with findings from the edge analysis, providing evidence that growth zones in astericus otoliths of both species can be interpreted as annuli.

African Zoology 45(1): 133–138 (April 2010)

Author Biographies

Henning Winker
Department of Ichthyology and Fisheries Science, Rhodes University, P.O. Box 94, Grahamstown, 6140 South Africa
Bruce R. Ellender
Department of Ichthyology and Fisheries Science, Rhodes University, P.O. Box 94, Grahamstown, 6140 South Africa
Olaf LF Weyl
South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, 6140 South Africa
Anthony J. Booth
Department of Ichthyology and Fisheries Science, Rhodes University, P.O. Box 94, Grahamstown, 6140 South Africa
Published
2017-05-01
Section
Articles

Journal Identifiers


eISSN: 2224-073X
print ISSN: 1562-7020