Oral Presentation Australian Society for Fish Biology Conference 2024

Fish community change associated with fishway construction - Buchan Weir Rock Ramp Fishway (111125)

Tim Marsden 1 , Thomas Molloy 1 , Melinda Scanlon 1
  1. AFPS, Fern Bay, NSW, Australia

The Buchan River in East Gippsland, Victoria, is an integral part of the Snowy River catchment, hosting a variety of native and threatened fish species. To enhance fish passage a rock ramp fishway was constructed on Buchan Weir, the only barrier within the system. This study aimed to evaluate the impact of this new infrastructure on local fish communities. Baseline and post-construction fish community sampling was conducted at multiple sites upstream and downstream of the weir using electrofishing and at the weir using trapping methods. Pre-construction sampling recorded 457 fish from seven species, while post-construction sampling captured 631 fish from eight species, indicating a positive response to the fishway installation. Key findings include an increase in species diversity and catch rates, particularly upstream where previously isolated habitats are now accessible, and the passage of threatened species through the fishway, with the rock ramp fishway also providing habitat for various fish species and size classes, thereby enhancing rocky habitat availability and ecological connectivity.