A telemetry experiment on spotted grunter Pomadasys commersonnii in an African estuary

  • SE Kerwath Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa; current address: Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa
  • A Götz Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
  • PD Cowley South African Institute for Aquatic Biodiversity, Private Bag X1015, Grahamstown 6140, South Africauth Africa
  • WHH Sauer Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa
  • C Attwood Marine and Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa
Keywords: estuary, fish behaviour, fish movement, <i>Pomadasys commersonnii</i>, telemetry

Abstract

The feasibility of using telemetry equipment to study the movements of estuarine-associated fish in South Africa was investigated by conducting a tracking experiment on spotted grunter Pomadasys commersonnii in the East Kleinemonde Estuary. The telemetry equipment comprised two VEMCO V8 transmitters and a VEMCO VR60 receiver linked to a directional hydrophone. Field experiments demonstrated that the equipment's maximum detection range was 400m. The transmitters were tuned to different frequencies, and interference between these was found to be negligible. The accuracy of locating the transmitter equalled the previously determined Global Positioning System (Garmin GPS 12) accuracy of approximately 5m. Two fish were tracked over a seven-day period. The fish preferred the lower reaches of the estuary where they made repeated and prolonged use of some areas. A tank experiment was conducted to examine the effects of the transmitter implantation. Fish recovered quickly after the surgical procedure, and no differences in swimming behaviour and growth rates were found between these fish and the controls.

Keywords: estuary; fish behaviour; fish movement; Pomadasys commersonnii, telemetry

African Journal of Marine Science 2005, 27(2): 389–394
Published
2005-11-04
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X