The spatial ecology of adult Labeobarbus marequensis and their response to flow and habitat variability in the Crocodile River, Kruger National Park

Abstract

The spatial movement of Labeobarbus marequensis was evaluated by attaching radio transmitters to 16 adult fish and tracking them from August 2009 to July 2012 in the Crocodile River, Kruger National Park, South Africa. Monthly monitoring surveys acquired 1 620 manual and 64 499 remote observations. Results showed adult L. marequensis did not participate in any migrations. Habitat preferences for L. marequensis were deep runs and fast glides, and there was disproportionately high use of submerged boulders as a cover feature. Tagged individuals also made use of rapids and pools, however, avoided shallow sandy slow glides. There was a reduced activity response of tagged individuals to rapid changes in water discharge. Continued changes in flow and instream habitat might threaten the Crocodile River population. Additional investigation into the effect of altered flows and associated habitat availability to the movement of L. marequensis is needed to better understand the effect of anthropogenic water resource use on L. marequensis in the Crocodile River.

Keywords: biotopes, cover feature, diel movement, radio-telemetry, water discharge, yellowfish