Oral Presentation Australian Society for Fish Biology Conference 2017

Freshwater catfish, Tandanus bostocki, move further and maintain larger home ranges during elevated flow in a regulated river, Western Australia (#74)

Leah Beesley 1 , Paul Close 1 , Matthew Long 1 , Michael Moroz 1 , Daniel Gwinn 2 , Wayne Koster 3 , Timothy Storer 4
  1. UWA, Albany, WA, Australia
  2. Biometric Research, Albany, WA, Australia
  3. Arthur Rylah Institute, Melbourne, Vic, Australia
  4. Department of Water, Perth, WA, Australia

Movement and migration of fish can be important to the completion of life cycles and the persistence of meta-populations. However, fish movement can be impacted by river regulation if it disconnects habitats and removes the hydrological cues required. Managed water releases, i.e., environmental flows, can be used as a restoration tool; however, their efficacious design and implementation requires a robust understanding of flow-ecology relationships. In this study we used radio telemetry to investigate whether river discharge influenced the movement of Tandanus bostocki, a plotisid fish endemic to south-western Australia and impacted by regulated river flows. Movement was assessed for 15 adult fish (males, females) at three temporal scales: bihourly, daily around a flow pulse and weekly. Movement of T. bostocki was strongly associated with elevated river flows, with fish moving downstream once flow exceeded 50 Ml/d, although the average distance travelled was relatively modest (< 800 m). While fish maintained larger home ranges during seasonally elevated baseflow, the linear distance moved by individuals per unit time did not vary with baseflow magnitude. We constructed flow-movement models that support a link between flow and movement of T. bostocki. The study highlights the importance of managing base-flow, and the magnitude, duration and recession rate of elevated flow events, to facilitate both localised and larger scale movements in regulated rivers.