The Flow-MER Border Rivers, Barwon and Namoi (BBN) fish monitoring program, a collaboration between Griffith University, La Trobe University, and NSW Fisheries, was established to build a long-term evidence base for environmental water management in the region. The program comprises two complementary components: area-scale monitoring, focused on small-bodied native fish in off-river habitats using a suite of methods (backpack electrofishing, small fyke nets, seine nets and box traps) specifically designed to target species that can be under-represented in conventional, boat-based riverine survey approaches; and basin-scale monitoring, using boat electrofishing in main-stem watercourses.
Area scale sites across the three catchments were stratified by aquatic habitat type (riverine, floodplain, palustrine and lacustrine), with additional in-river littoral sites included where off-river habitat was unavailable or inaccessible. This design allows fish assemblages to be compared across catchments and across the habitat gradient connecting rivers and their floodplains.
Here we present findings from the first year of monitoring in the BBN selected area. A range of small-bodied and off-river-dependent native fish species have been collected, including evidence of recruitment in oxbow and floodplain wetlands. These early findings suggest that, when targeted appropriately, floodplain and wetland habitats are actively supporting recruitment for a range of native species, with early comparisons suggesting the area- and basin-scale components are capturing different segments of the BBN fish community.
As one of Flow-MER's newer selected areas, BBN's monitoring dataset is still in its early stages relative to some other selected areas. We outline the program's design and aim, and present these first-year results as a foundation for the longer-term monitoring needed to understand native fish responses to flow and habitat management in the BBN catchments.