Fish passage in the Murray‐Darling Basin, Australia: Not just an upstream battle

Abstract

Summary Construction of instream barriers, preventing fish from accessing spawning, nursery and feeding habitat, is a major issue impacting fisheries sustainability throughout the world. Since European settlement, development in the Murray-Darling Basin for irrigation and potable water supplies has led to the construction of over 10,000 barriers to fish movement. The Native Fish Strategy listed fish passage as a major driving action and was proactive in progressing cost-effective solutions to help inform large-scale rehabilitation programmes. The strategy identified a list of high-priority barriers for mitigation works based on feedback from jurisdictional agencies. Research initiatives were then implemented, with measurable outcomes, to help address key knowledge gaps. Research demonstrated that a project to restore passage to the Murray River main channel was meeting all ecological and engineering objectives. Follow-on work identified low-cost mechanisms to improve the effectiveness of existing fishways without compromising ecological functionality. The Native Fish Strategy was also explicit in addressing fish passage issues at irrigation infrastructure and wetland regulators. Work to minimise these impacts included quantifying the scale of irrigation-associated infrastructure and also optimising screen designs to be retrofitted to pump systems to prevent fish entrainment. Options to enhance lateral movement were also identified. The objective of this study is to summarise the fish passage issues progressed by the Native Fish Strategy to develop basin-wide solutions to enhance fish passage over the long term.

The future of fish passage science, engineering, and practice

“…However, the concept that migration routes for fish can be universally reinstated through the installation of fishways resulting from the transfer of expertise and infrastructure between and within geographical regions has generated substantial debate (Kemp, ). Some successes have been reported (Barrett & Mallen‐Cooper, ; Baumgartner, Zampatti, Jones, Stuart, & Mallen‐Cooper, ; Parsley et al., ), especially at sites where solutions were specifically developed to meet target species and hydrology. But the precarious conservation status of native population reduction of migratory species in South America (Agostinho, Gomes, Fernandes, & Suzuki, ; Agostinho, Gomes, & Latini, ), and the disrupted river connectivity throughout Africa (Jewitt, Goodman, Erasmus, O'Connor, & Witkowski, ; Nel et al., ; Wasserman, Weyl, & Strydom, ) and Asia (Dudgeon, ), clearly indicates that these strategies cannot be applied everywhere.…”

Comparative movements of four large fish species in a lowland river

“…Indeed, the MDB rates amongst the most highly affected river basins in the world with only 40–50% of its water course length remaining free‐flowing (Liermann et al , ). It is suggested that >10 000 barriers have been constructed on MDB rivers and floodplain channels that pose barriers to fish passage (Baumgartner et al , ).…”

Laying the foundations for fish recovery: The first 10 years of the Native Fish Strategy for the Murray‐Darling Basin, Australia

“…It included a significant multijurisdictional monitoring programme, which has resulted in continual adaptive, cost‐effective improvement of fishway designs and approaches (Baumgartner et al . ). Most fishways have been fitted with an automated PIT (Passive Integrated Transponder) telemetry system to assess the effectiveness of the fishways with more than 35 000 fish tagged and now at liberty along the river Murray (Barrett ).…”