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

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.