Long Oral Presentation 11th Australian Stream Management Conference 2024

Improving outcomes for a highly fragmented, poorly known River Blackfish population in peri-urban Melbourne (#9)

Matthew C Le Feuvre 1 , Simon Treadwell 1 , Teresa J Mackintosh 2
  1. Jacobs, Melbourne, VIC, Australia
  2. Waterways and Catchment Operations, Melbourne Water, Melbourne, VIC, Australia
  • Watsons Creek is a seasonal, rainfall-driven creek flowing through bushland, agricultural areas and acreages on the fringe of Melbourne. Historically, Watsons Creek supported a small, fragmented population of River Blackfish, which were a favoured food by the Wurundjeri Woi-wurrung. However, the status of the population was unknown, particularly with flows declining over the past 20 years. Recent eDNA monitoring showed that River Blackfish remained in the creek. Melbourne Water wished to better understand the River Blackfish population in Watsons Creek and the distribution of refuge habitat, and to develop management actions to improve Blackfish habitat.
  • We mapped the distribution and quality of refuge pools along Watsons Creek. We then surveyed a subset of refuge pools for River Blackfish. Based on the results of the surveys, we developed management actions to improve Blackfish habitat. To share knowledge, the Wurundjeri Woi-wurrung Cultural Heritage Aboriginal Corporation (Narrap Rangers) were involved in surveys and refining management actions.
  • We found that potential refuge pools were present along much of Watsons Creek. However, River Blackfish were limited to a short reach of the creek, where groundwater likely supports permanent pools and flows are less flashy. While the population appears healthy, recruitment is limited. Management actions to improve habitat for local Blackfish are largely limited to the landscape scale.
  • The outcomes of the project highlight the importance of catchment-scale management actions to improve outcomes for aquatic values. These can include catchment-wide measures to minimise water quality impacts, particularly runoff from unsealed roads, and protecting groundwater-surface water interactions.
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