Restoration & Recovery

Restoration & Recovery is about bringing back freshwater fish.

This research theme supports the wellbeing of fish in NSW aquatic ecosystems and helps people provide critical care to fish when times get tough. The theme prioritises and drives uptake of best-practice management approaches, conservation techniques and water infrastructure technologies to save water, save money and protect fish.

Theme Leader: Dr Craig Boys

Impact highlights

  • Pioneering research and leading multidisciplinary international teams in the design of fish-friendly infrastructure in NSW, Asia, Europe and the U.S.A.
  • Creating a potential $3.6b industry bringing best-practice screening technology to NSW water pumps and channels, benefitting business and biodiversity.
  • Developing ecology-based mitigation targets to complement engineering approaches, leading to predictive capacity to manage water in ways that protect native fish.

Research focus

  • Identifying how fish use habitats and what works best to restore habitat quality, quantity and access for fish, to guide restoration action.
  • Quantifying how fish are impacted by water infrastructure and the value of adopting new technologies, working with the manufacturing and agricultural sectors.
  • Understanding and testing innovative ways to provide the conditions fish need to live, feed and breed, to survive droughts and produce thriving, diverse populations.
  • Developing effective hatchery breeding programs using data on fish life cycles and genetics, to improve the resilience of threatened species.

Current projects

Fish passage

Most native fish species need access to a range of habitats to complete their life cycle but have their migrations through rivers and between catchments blocked by water infrastructure. Our research deepens the understanding of how dams, weirs, hydropower (traditional and pumped) and fishways can be designed and operated to facilitate the safe upstream and downstream movement of fish. Key research includes both the optimisation of designs as well as assessing their effectiveness. Project Lead: Dr Craig Boys

Modern fish screens

NSW DPI is driving uptake of modern fish-protection screens for water offtakes. This technology protects 90% of native fish, while supporting regional communities. We’ve developed a new best-practice to guide manufacturers to help deliver real benefits for fish and farms. Find out more at Project Lead: Dr Craig Boys

Cold water pollution

Large instream structures (like dams and weirs) can alter the thermal conditions of rivers – reducing water temperatures by up to 16°C below natural. NSW DPI Fisheries is working to understand how fish are affected by these unnatural water temperatures and guide management actions that best support the health and persistence of our native fish populations. Project Lead: Dr Laura Michie


Fish stocking – raising fish in hatcheries and releasing them into the wild – is a key action used by conservation managers to increase the abundance of fish populations. FishGen is collaborative project that compiles genetic data on parent fish housed in hatcheries. This information is used to identify whether the fish captured in natural waterways have come from a hatchery or from natural spawning events. Project Lead: Dr Meaghan Duncan

Emergency response

Drought and bushfires have significant impacts on native fish populations. Our research supports pre-emptive and immediate responses to these events. This includes assessment of water aerators to avoid fish kills, post-fire surveys to assess populations of threatened species and monitoring of conservation actions such as riverbank revegetation. Project Lead: Dr Craig Boys

Key publications

  • Boys, C. A., Baldwin, D. S., Ellis, I., Pera, J. and Cheshire, K. (2021).  Review of options for creating and maintaining oxygen refuges for fish during destratification-driven hypoxia in rivers. Marine and Freshwater Research 73: 200-210.
  • Boys, C. A., Pflugrath, B. D., Mueller, M., Pander, J., Deng, Z. D. and Geist, J. (2018).  Physical and hydraulic forces experienced by fish passing through three different low-head hydropower turbines. Marine and Freshwater Research 69: 1934-1944.
  • Boys, C. A., Pflugrath, B., Singhanouvong, D., Phonekhampheng, O., Phommavong, T., Vorasan, P., Homsombath, K., Baumgartner, L., Fowler, T. and Kelly, B. (2020). Improving the design of irrigation infrastructure to increase fisheries production in floodplain wetlands of the Lower Mekong and Murray-Darling Basins. Final Report to the Australian Centre for International Agricultural Research No. FIS/2012/100. NSW Department of Primary Industries, Taylors Beach, 79 pp.
  • Boys, C. A., Rayner, T. S., Baumgartner, L. J. and Doyle, K. E. (2021). Native fish losses due to water extraction in Australian rivers: evidence, impacts and a solution in modern fish- and farm-friendly screens. Ecological Management & Restoration 22:134-144.
  • Doyle, K. E., Silva, L. G., Ning, N., Brambilla, E. M., Boys, C. A., Deng, Z. D., Fu, T., Du Preez, J. A., Robinson, W. and Baumgartner, L. J. (2020).  Gambusia holbrooki survive shear stress, pressurization and avoid blade strike in a simulated pumped hydroelectric scheme. Frontiers in Environmental Science 8: 201.
  • Stocks, J.R., Walsh, C.T., Rodgers, M.P. and Boys, C.A. (2019). Approach velocity and impingement duration influences the mortality of juvenile Golden Perch (Macquaria ambigua) at a fish exclusion screen. Ecological Management & Restoration 20:136-141.
  • Michie L. E., Thiem J. D., Facey J. A., Boys C. A., Crook D. A., and Mitrovic S. M. (2020). Effects of suboptimal temperatures on larval and juvenile development and otolith morphology in three freshwater fishes: implications for cold water pollution in rivers. Environmental Biology of Fishes 103:1527-1540.
  • Silva A. T., Lucas M. C., Castro-Santos T., Katopodis C., Baumgartner L. J., Thiem J. D., Aarestrup K., Pompeu P. S., O'Brien G. C., Braun D. C., Burnett N. J., Zhu D. Z., Fjeldstad H.-P., Forseth T., Rajaratnam N., Williams J. G., and Cooke S. J. (2018). The future of fish passage science, engineering, and practice. Fish and Fisheries 19:340-362.
  • Rourke M. L., Robinson W., Baumgartner L. J., Doyle J., Growns I., and Thiem J. D. (2019). Sequential fishways reconnect a coastal river reflecting restored migratory pathways for an entire fish community. Restoration Ecology 27:399-407