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Despite significant investment, fish conservation efforts fall often short due to barriers like weirs, dams, and culverts, that obstruct critical fish migration in rivers and freshwater systems. With tens of thousands of barriers in place, fishways are the most widely used mitigation strategy. However, no universal or “silver bullet” fishway exists, and traditional designs are frequently costly. As a result, innovative and alternative fishway solutions are emerging.����

To tackle this challenge, a multidisciplinary research team from the Centre for Ecosystem Science (CES) in BEES and the Water Research Laboratory (WRL) in CVEN has been pioneering the development of pipe fishways. These systems are designed to provide cost-effective, adaptable, and reliable solutions for safe fish migration both upstream and downstream past barriers. Pipe fishways are scalable, retrofittable, require less water, quick to install, making them suitable for seasonal or emergency use. They also support the passage of a wide range of species, including smaller and weaker-swimming fish.����

Our team combines expertise in hydraulic engineering and aquatic ecology, supported by state-of-the-art facilities for fish husbandry, hydraulic physical modelling, and dedicated fieldwork equipment with specialised technical support. Through rigorous experimentation, including live fish trials, hydrodynamic testing, and numerical modelling, we are developing innovative and evidence-based pipe fishways that can be deployed across a wide range of environments to restore connectivity in freshwater ecosystems.

Approach:

There are two key elements: fish attraction into a pipe chamber and safe fish transport through a vertical riser. The attraction design concept involves applying existing fishways’ knowledge to attract free-swimming fish into a chamber. The transport process utilizes the acceleration of flows in the tube system to move the chamber contents, with the fish, vertically through a riser pipe at near atmospheric pressure and over the dam wall.

Progress to date:

The Tube Fishway was our foundational pipe fishway and has been under continuous development since 2019. In controlled laboratory settings, the system has successfully lifted native Australian fish species over vertical heights of up to eight metres. Temporary field trials at five diverse sites across New South Wales and Queensland have further demonstrated the Tube Fishway’s hydraulic performance and operational reliability under a variety of environmental conditions. To date, twelve fish species have been safely lifted with the Tube Fishway in lab and field trials.

Underpinning research:

The development and testing of innovative pipe fishways are underpinned by interdisciplinary research on fish attraction, passage and safety of fish. Under controlled laboratory conditions, systematic research has examined how factors such as attraction flow, pipe dimensions, entrance geometries, and lighting can be manipulated to encourage fish motivation to enter a piped entrance. These experiments have demonstrated that fish can be reliably guided into pipe fishways. These laboratory findings have been validated through field-based attraction trials, confirming their real-world ecological applicability.��

Building on our fish attraction research, we further investigated the motivation of a range of native Australian fish species, such as silver perch (Bidyanus bidyanus) and golden perch (Macquaria ambigua), to voluntarily swim through a 3 m high pipe with hypobaric pressure gradient. This research underpins the fundamental biological operation of the siphon fishway.��

To ensure that fish can be transported safely and without injury through pipe fishways, we systematically evaluated hydrodynamic conditions within key pipe components, including entrances, expansions, contractions, and bends. This research integrated laboratory-based hydrodynamic measurements with Lagrangian pressure and acceleration sensors, live fish observations, and computational fluid dynamics (CFD) modelling. The combined approach provided unique insights into hydrodynamic thresholds that are biologically safe for fish, offering critical guidance for the design of fish-friendly pipe transport systems.

The next steps:

1. Conduct longer-term and larger-scale field trials of the Tube Fishway.

2. Implement field trials of siphon fishway and cascading vortex pipe fishway.
3. Systematically evaluate the efficiency of pipe fishways compared to more traditional fishways.
4. Undertake supplementary research on fish attraction and safety across a wider range of fish species, sizes and life-history stages.

5. Develop and test downstream passage solutions for barriers.��

References

• Cox, R. X., & Felder, S. (2025). Injury-free transport of fish through closed conduit components. Journal of Ecohydraulics, 0(0), 1–16. ��

• Cox, R. X., Senevirathna, L., Mulligan, S., & Felder, S. (2025). Particle tracking to assess safe fish transport through closed conduit components. Ecological Engineering, 218, 107677. ��

• Jeremy, Y., Martino, J., Felder, S., Kingsford, R. T., & Suthers, I. M. (2025). Tackling Fish Passage Problems: Conservation Implications of Fish Ascending Hypobaric Pressure Gradients in a Pipe. Aquatic Conservation: Marine and Freshwater Ecosystems, 35(1), e70050. ��

• Martino, J. C., Suthers, I. M., Kingsford, R. T., Doyle, K. E., Baumgartner, L. J., & Felder, S. (2025). Pipe fishways: Opportunities and challenges for effective fish passage. Environmental Technology Reviews, 14(1), 471–487. ��

• Farzadkhoo, M., Jadraque, D., Kingsford, R. T., Suthers, I. M., & Felder, S. (2024). Entrance geometries of closed-conduit fishways to attract juvenile fishes. Ecological Engineering, 209, 107421. ��

• Cox, R. X., Kingsford, R. T., Suthers, I., & Felder, S. (2023). Fish Injury from Movements across Hydraulic Structures: A Review. Water, 15(10), Article 10. ��

• Farzadkhoo, M., Kingsford, R. T., Suthers, I. M., & Felder, S. (2023). Flow hydrodynamics drive effective fish attraction behaviour into slotted fishway entrances. Journal of Hydrodynamics, 35(4), 782–802. ��

• Farzadkhoo, M., Kingsford, R. T., Suthers, I. M., Geelan-Small, P., Harris, J. H., Peirson, W., & Felder, S. (2022). Attracting juvenile fish into Tube Fishways – roles of transfer chamber diameter and flow velocity. Ecological Engineering, 176, 106544. ��

• Peirson, W. L., Harris, J. H., Suthers, I. M., Farzadkhoo, M., Kingsford, R. T., & Felder, S. (2022). Impacts on fish transported in tube fishways. Journal of Hydro-Environment Research, 42, 1–11. ��

• Peirson, W. L., Harris, J. H., Kingsford, R. T., Mao, X., & Felder, S. (2021). Piping fish over dams. Journal of Hydro-Environment Research, 39, 71–80. ��

• Harris, J. H., Peirson, W. L., Mefford, B., Kingsford, R. T., & Felder, S. (2019). Laboratory testing of an innovative tube fishway concept. Journal of Ecohydraulics, 5(1), 84–93.

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