Governments have a strong vision for future development in northern Australia, including the expansion of irrigated agriculture. However, we need to further our knowledge to understand the ecological impacts of changes to river flows. Making decisions involving trade-offs between the water needs of communities, the environment and future industries is made more challenging without this knowledge.
The need to understand how our river systems work is particularly pressing in the Northern Territory’s Daly River catchment. Most of the Northern Territory’s current irrigation activity occurs in the Daly, and its reliable groundwater reserves and relatively good soils make it a prime candidate for further agricultural development. The Daly River is a unique, perennial river system in northern Australia that supports an abundance of aquatic wildlife, including 90 species of fish and eight species of freshwater turtle. The river is highly valued by the region’s Indigenous people for cultural purposes and as a food source. Furthermore, the river is arguably home to some of the best recreational fishing in northern Australia.
To better assess the impacts of further water development on these values, we need an increased ecological understanding of the river. A priority is the risk of reduced flows during the dry season and understanding the effect on the river’s ecology.
The amount of water within the river, particularly during the dry season, as well as the timing of flood pulses in the wet season, is important for supporting the river’s wildlife, including fish and turtles. This project is determining the water requirements of key environmental assets within the river and improve our capacity to predict the impact of current and future water allocations. The outcomes will inform water policy, water allocation planning and fisheries policy and management of the Daly River.
This project is building on previous research in the river, including research by the Tropical Rivers and Coastal Knowledge (TRaCK) research hub, the NERP Northern Australia Hub and the Northern Territory Government. The project is incorporating existing research, along with targeted research activities including remote sensing, habitat mapping and ecological studies to produce models that explore the relationship between river flows and key ecological assets of the Daly River system.
The research is taking place in the Daly River catchment. Field work is being conducted from Katherine township to Nauiyu/Daly River crossing where the impact of dry season water extraction on in-stream flows is predicted to be the greatest.
Roberts, B.H., Morrongiello, J.R., King, A.J., Morgan, D.L., Saunders, T.M., Woodhead, J. & Crook, D.A. (2019). Migration to freshwater increases growth rates in a facultatively catadromous tropical fish. Oecologia. https://doi.org/10.1007/s00442-019-04460-7
Turschwell, M.P., Stewart-Koster, B., King, A.J. Pusey, B., Crook, D., Boone, E., Douglas, M.M, Allsop, Q., Jackson S. & Kennard, M.J. (2019). Flow-mediated predator–prey dynamics influence fish populations in a tropical river. Freshwater Biology. https://doi.org/10.1111/fwb.13318
Keller, K., Allsop, Q., Brim Box, J., Buckle, D., Crook, D., Douglas, M.M., Jackson, S., Kennard, M., Luiz, O., Pusey, B., Townsend, S. & King, A. (2019). Dry season habitat use of fishes in an Australian tropical river. Scientific Reports. 9. 5677.
Martin Kainz presents how fatty acids can be used as biomarkers in analysing food webs and trophic flow.
David Crook discusses how otolith chemistry can help explain and document fish life history.
The project is being led by Associate Professor Alison King at Charles Darwin University. Associate Professor King is being supported by researchers from Charles Darwin University, Griffith University, Northern Territory Department of Environment & Natural Resources and Northern Territory Department of Primary Industry and Fisheries.
Alison King, Charles Darwin University