A multi-faceted approach for evaluating fishway performance in south-eastern Australia
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Date
2015-06-24
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Publisher
University of Massachusetts Amherst
Abstract
In the coastal rivers of south-eastern Australia 70% of fish migrate at some stage between the rivers and estuary to complete their life cycle, predominantly as catadromous and amphidromous migrations. A major threat to diadromous fishes in this region is the construction of artificial barriers, such as dams, weirs and road crossings. Traditionally, fishways in Australia were based on those designed to pass salmonids, thus limiting fish passage for the comparatively poorly swimming Australian native species. However, in the past few decades fishway design has been refined to accommodate native species’ swimming ability and wide range of body sizes (40- 1000mm). Ongoing monitoring programs have facilitated the refinement of modern fishway design to ensure successful passage of the target community.
The Hawkesbury-Nepean and Shoalhaven rivers are the second and fifth largest regulated coastal river systems within the state of New South Wales. Barriers in these systems were retrofitted with either vertical slot or high-dam fishways completed over the last six years, together with new environmental flows. Sampling techniques for fishway evaluation on these rivers includes monitoring fish communities above and below the barrier; PIT tagging to assess timing of migration through fishways; and fishway entrance and exit trapping to assess the success of the fishway at passing individual species. Modern sampling techniques such as genetics and stable isotope analysis (SIA) are also being used on historically fragmented habitats to detect changes in population genetic structure and trophic shifts. Finally, analysis of fish movement (derived via acoustic telemetry) in response to environmental variables is providing detailed information on potential migration cues and flow regimes required to stimulate fish movement. This multi-faceted research approach not only provides empirical and real-time data for evaluating the performance of fishways in improving fish passage, but also informs operational managers on their efficiency and assists engineers in refining future fishway design.
Description
Keywords
Coastal regions, Australia, Fishes, Estuaries, Life cycle, Fish passage facilities, Migration, Dams, Roads, New South Wales, Stable isotopes
Citation
Walsh, C., Duncan, M., Paull, T., Reinfelds, I., Mazumder, D. & Giligan, D. (2015). A multi-faceted approach for evaluating fishway performance in south-eastern Australia. Paper presented at Fish Passage 2015 – International conference on river connectivity best practices and innovations, 22- 24 June 2015, Groningen, Netherlands. Retrieved from:https://scholarworks.umass.edu/fishpassage_conference/2015/June24/62/