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Native Fish Outcomes

A key objective of the Sustaining Riverland Environments (SRE) program is to improve habitat connectivity and population resilience of native fish species on a landscape-scale in South Australia’s Riverland.

To assist in achieving this objective, the Native Fish Outcomes project (NFO) is delivering 3 components:

Re-snagging - installation of tree root balls (snags) in water bodies for native fish habitat
Fish screening - promoting and increasing the use of fish screens throughout the River Murray
Lock 2 Reach - a number of sites have been identified for infrastructure solutions and habitat assessments. Data collected will support the general implementation of screens and aid in developing business cases for priority future funding opportunities.

Additionally, the project is undertaking Murray cod monitoring and considerable research and management actions aimed at reversing the decline of this iconic species.

Re-Snagging

The re-snagging component works with communities and First Nations groups to reinstate instream woody habitat, also known as ‘snags’, to improve habitat condition and availability, and hydraulic variability at a micro-scale. This will contribute to an increase in abundance and diversity of native fish and other aquatic organisms, as well as improve connectivity between species populations in the SA River Murray. This component will also establish a re-snagging delivery program model to be continued for future funding opportunities.

Find out more on the Re-snagging: restoring in-stream habitat webpage.

Fish Screening

In the Murray-Darling Basin, irrigation offtakes have been demonstrated to remove aquatic biota (notably fish eggs, larvae and juveniles), generally resulting in mortality, but there is currently no data on the actual degree of fish entrainment in South Australia or the varying impacts of different sized offtakes.

The Fish Screening component will be undertaken by the South Australian Research and Development Institute (SARDI) and consist of two elements:

1. Ecological analysis of fish entrainment trials

The fish entrainment trials investigated the potential ecological benefit of irrigation offtake screens in the South Australian River Murray. Trials were conducted over a 4-week period in spring/summer 2024-25 and involved examining the fish caught in portable pumps used for environmental watering of off-channel wetlands to assess fish entrainment. These pumps had various offtake sizes (150 mm to 500 mm diameter) and are similar to irrigation offtakes, representing a useful experimental apparatus for the trials.

2. Irrigator interview

The second component involved interviewing 20 irrigators to ascertain their knowledge of fish screens, attitudes towards their use and other key factors that could potentially limit uptake of the technology.

Interview questions were developed by DEW, with assistance from the New South Wales Department of Planning and Environment, with the aim of understanding irrigators’ backgrounds, land/organisation structure and preferred methods of communication, as well as what measures can be taken to encourage uptake in the future.

Lock 2

Subject to approvals and funding, this component includes works to improve hydraulic connectivity and enable management actions to achieve throughflows or return flows to the River Murray, returning valuable nutrients to the system to support healthier native fish populations. Some of the existing infrastructure in the Lock 2 Reach requires upgrading to improve safety and operability, and small modifications could further enable better through flow management, improve fish passage opportunities and provide a wider diversity of management actions.

To assist in achieving SRE's objective of improving habitat connectivity and population resilience of native fish species, a number of sites in Lock 2 were identified for opportunities to improve environmental watering, increase the provision of habitat and assess passage for native fish through infrastructure solutions and habitat assessments. Identified sites include:

Nigra Creek-Schillers Lagoon Complex - flows around Lock 2 and provides habitat for a range of native fish and other native species that would benefit from a more dynamic watering regime and improved hydraulic conditions for passage and breeding events.
Yarra Wetland Complex - has potential to support salt tolerant native fish species, with habitat feasibility assessments required to identify further opportunities to support recovery efforts of threatened native fish species, including for Murray hardyhead.
Wigley Reach and Parcoola wetlands - two temporary pumped wetlands that currently support a diversity of native flora and fauna species. Small infrastructure solutions would better integrate wetland management with weir pool manipulation and enable the return of valuable nutrients to the river through return flows, benefitting a range of biota, including native fish.

Murray cod monitoring

Historically, the Murray cod was one of the most abundant fish species in the River Murray, but populations declined throughout the 1900s due to the impacts of river regulation, habitat loss, overfishing and invasive species.

To address this issue, the Sustaining Riverland Environments (SRE) program, funded by the Murray-Darling Basin Authority and managed by the South Australian Department for Environment and Water, is undertaking considerable research and management actions aimed at reversing the decline of this iconic species. Activities include re-snagging, fishway construction, investigations of weir pool lowering and restoration of flowing creeks, which will complement the delivery of water for the environment to boost numbers of Murray cod in the South Australian River Murray.

To provide effective management interventions, SRE is also undertaking research to gain better understanding of the species, including its habitat use and movement in the lower River Murray.

Find out more on the Murray Cod Monitoring page.

Activity sheets

Get involved

We are committed to working with First Nations people, local communities and the broader South Australian community throughout the life of the SRE program.

Subscribe to our email list for updates and SRE engagement opportunities.

Contact us

Email us at dew.sreprogram@sa.gov.au
Call the Department for Environment and Water (DEW) on (08) 8204 1910.

More information

Department for Environment and Water social media

SRE project pages

Weir pool manipulation

Other resources

The Sustaining Riverland Environments program is a $37.6 million program funded by the Australian Government through the Murray-Darling Basin Authority and delivered by the Government of South Australia through the Department for Environment and Water.