Lower Darling-Baaka Recovery Reach

The importance of this Recovery Reach

The Lower Darling River is significant for native fish in the Murray-Darling Basin. Iconic species such as Golden perch, Murray cod, Silver perch and Freshwater catfish, as well as a number of important small-bodied native fish species, live in this special river. The Darling River supports the breeding and recruitment (growth and survival) of fish, with Golden perch adults, for example, spawning upstream so that larvae and young fish drift downstream. As they drift they grow, so by the time they reach the Menindee Lakes, there are juveniles and adults able to repopulate, both in an upstream and downstream direction. Recent science demonstrates that Golden perch in the Murray system (from Echuca down to the Lower Lakes in South Australia) are often those that began life in the Darling River.

The Lower Darling River Murray cod population is particularly important for the recovery of adjacent populations in the mid and lower Murray River system that in recent years, have suffered severe declines with blackwater fish deaths across thousands of river kilometres.

Recovering the Lower Darling

NSW Department of Primary Industry, in collaboration with other State and Commonwealth agencies and organisations, are implementing management actions to protect and recover native fish populations.

Long Term

Increasing restocking efforts
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Improving fish passage through the region
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Rehabilitating aquatic habitat at priority reaches of the river
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Working with other state and federal agencies Engaging and building capacity with local communities, to deliver further management actions to support the movement, breeding and recruitment of native fish

School children helping to restock Murray cod and Golden perch

Short Term

Water quality monitoring to inform real time water management an minimise risk to fish stocks

Identification and mapping of refuge pools to focus conservation and recovery actions

Creation of artificially aerated refuge areas in the Lower Darling during periods of no flow
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Relocation of fish from diminishing pools to better quality waterbodies
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Mapping of key habitat types (snags, river benches) to inform delivery of flows through the Lower Baaka-Darling and ensure best outcomes with limited water volumes
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Community engagement and capacity building regarding water management and ecological recovery following the fish kills
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Fish community monitoring to track recovery of local fish stocks and highlight potential risks.
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Progress implementation of fish passage strategies to ensure fish can move to where they want to be!
Increasing restocking efforts

Recent updates (August 2024)

NSW Government response to OCSE Recommendations

The NSW Government has committed $25 million in new funding over 4 years for a suite of short, medium, and long–term actions that respond to the recommendations of the Office of the NSW Chief Scientist and Engineer. DPIRD Fisheries in collaboration with partner agencies and community will lead specific fish focused actions including:
- More than $6.5 million to trial state-of-the-art temporary fish passage technologies such as a new retrofitted tube design which allows fish to pass over weirs and river barriers to escape poor water quality events and reduce the chance of future mass fish deaths.
- $6 million to complete a detailed business case for permanent fish passage in the Lower Darling-Baaka and Menindee Lakes system which could restore 518km of connectivity between the northern and southern Murray-Darling Basin. This is in addition to the $2.3 million dollars committed by the Commonwealth Government for business case development.
- $600,000 shared with Western LLS for strategic planning for onground rehabilitation works to improve water quality, and ecological and cultural outcomes.

Fish passage focus
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‍With the announcement of funding commitments, early project planning works are now underway for the Menindee Fish Passage Program, with focus on upcoming stakeholder and community engagement events over the coming weeks. This will give the project team an opportunity to ask community members how they would like to be involved and engaged through the program. Other early project works currently underway include: Finalisation of funding agreements Development of detailed project plans and timelines Establishing a dedicated Menindee Fish Passage Delivery Team so we have the right mix of skills and resources to deliver the program Progressing the tender process for the temporary fishway trial, including an onsite meeting with interested proponents and agencies later this month.

Lake Menindee Outlet Regulator. Source: NSW DPI

SPOTLIGHT: Lower Darling-Baaka Fish Passage program

The Lower Darling Fish Passage Program was funded by the Commonwealth in 2020 following the 2018-2019 fish death events, with the objective to restore fish passage connectivity along the Lower Darling-Baaka by refurbishing existing fishways at Weir 32, Pooncarie and Burtundy weirs. After initial site investigations, discussions and recognising potential interactions from other NSW projects and a better understanding of costs, it was decided to remove construction phase for Weir 32 and Pooncarie Weir from the program, with the focus and funding shifted to Burtundy Weir.

Burtundy Weir
Phase 1 (pre-construction) of the program was completed in 2023 and delivered concept and detailed designs for the new fishway, site assessments, regulatory approvals, consultation and business case preparation. Phase 2 (implementation) will replace the current fishway with a contemporary vertical slot fishway that will significantly improve fish passage at the site over a wider range of flows. Construction is expected to commence in 2024 (subject to river conditions). The new fishway will also allow a wider range of species, age and size class of fish to pass upstream. This will provide a critical role in the Lower Darling-Baaka fish species assemblage distribution and ecology. The new fishway will not change current hydrology and continue to provide weir pool drought security during low flows.

Pooncaire Weir
A fishway functionality review was undertaken during Phase 1 of the Lower Darling Fishway Passage program to better understand the performance capabilities of existing fishways against contemporary designs. The vertical slot fishway at Pooncarie Weir was found to be under-performing and not providing appropriate conditions for optimum fish passage. A review recommendation was for a complete replacement of the fishway to address weir stability, poor operation at high flows, high fishway entrance turbulence, and high internal pool turbulence. Pooncarie Fishway is included in the detailed Business Case for permanent fish passage in the Lower Darling-Baaka and Menindee Lakes system.
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Weir 32
Similar to Pooncarie, the functionality review at Weir 32 found that the fishway was not meeting performance standards and was recommended for a complete replacement. Excessive turbulence both within the fishway and at the entrance was limiting movement of fish upstream. The Weir 32 fishway will also be included as a priority site under the detailed Business Case for permanent fish passage in the Lower Darling-Baaka and Menindee Lakes system that DPIRD Fisheries will be undertaking. The existing fishway at Weir 32 has been temporarily closed as a response to the mass fish deaths in 2023 to reduce biomass and oxygen demand within the Menindee town weir pool above Weir 32. A decision to open the fishway will be considered based on government and community consultation, as well as other important information such as river flows, water quality conditions, fish biomass and related fish passage activities.

Fish findings from the field

DPIRD Fisheries were busy in May and June, undertaking standardised electrofishing sampling in the Great Darling Anabranch and Lower Darling Baaka River. Sampling has been undertaken as part of numerous State and Commonwealth funded projects including the Lower Darling Recovery Reach (MDBA), Darling River Health (NSW DCCEEW) and Lower Darling-Baaka e-flows (CEWH) projects.

Initial insights from the field include:

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Catch rates of large-bodied native species Golden Perch and Murray Cod remain low upstream of Pooncarie, including upstream of Weir 32, following 2023 fish deaths.
Golden Perch catches were moderate downstream of Pooncarie, with catches dominated by adult and sub-adult fish and minimal evidence of recent recruitment.
Bony Herring continue to be abundant throughout the Lower Darling-Baaka River, with evidence of annual recruitment in most years.
Catch rates of Common Carp and Goldfish had decreased in comparison to 2023 levels, with limited evidence of recent recruitment.

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Additionally, a combination of targeted sampling and mathematical modelling funded by the CEWH and NSW Biodiversity, Conservation and Science Group, estimated that the Golden Perch population size in Lake Cawndilla in February 2023 was 1.59 million fish (at a single point in time).

Further targeted sampling has been undertaken in lakes Wetherell, Pamamaroo, Tandure, Cawndilla, Menindee, Balaka, and Bijijie to help inform up-to-date relative densities and size structure of Golden Perch for these systems.

Introduction to freshwater fishing operations

In early June 2024, DPIRD Fisheries delivered the ‘Introduction to Freshwater Fishing Operations’ program with the Barkandji community at Menindee. This innovative new program was developed as part of the NSW Government response to the OCSE independent review into the 2023 fish deaths in the Darling–Baaka River at Menindee. The program focused on building the Barkandji communities’ capacity to engage in potential economic opportunities in commercial fishing and broader freshwater actions.

Participants developed their skills in commercial fishing operations, freshwater fisheries research techniques and small vessel handling. The week brought together a group of over 40 people including Barkandji Rangers, Barkandji Elders, Menindee community members, commercial fishers and DPIRD Fisheries staff. The program continues to build positive relationships between DPIRD Fisheries and the broader Barkandji community.

Outcomes from the training included:

Increasing the Barkandji Rangers capacity to assist Fisheries; Freshwater Ecosystems Research in eDNA sample collection and electrofishing; Significant progress to achieving their Coxswain Grade 3 vessel qualification; The group gained an in depth understanding of freshwater commercial fishing operations with several participants identified to go on and assist commercial fishers as crew; and 1 tonne of Carp from the Lower Darling-Barka was removed in just 3 days!

Sekola Havilli, Project Officer from the Barkandji Native Title Prescribed Body Corporate said:

“Fishing and caring for our waterways are part of who we are. This training supports our cultural practices and aligns with our commercial goals, helping us to employ more Indigenous people and enable them to become self-employed.”

DPIRD Fisheries would like to thank the First Nations community for their involvement and support in this project. DPIRD Fisheries will continue to work with the Barkandji community who aspire to own and operate a multi-purpose commercial vessel equipped to assist with fish kill response, environmental monitoring contracts and commercial fishing opportunities.

What else has been done?

Investigating the 2024 fish deaths – The most recent update to the community (12th of April 2024) provided key insights into the most recent fish deaths. The dissolved oxygen levels at the Menindee Weir pool remain at adequate levels with water quality monitoring showing a decrease in water temperature and an increase in dissolved oxygen which remains above the critical threshold for fish health. The volumes of water being released from lakes Menindee and Pamamaroo were adjusted as a response to improved dissolved oxygen and to aid in the preservation of water resources in the upper lakes. Despite detailed investigations and sample analysis, no single factor has been identified as the cause of the fish deaths that began in February of 2024.

Restocking – So far NSW Fisheries have released Murray cod and Golden perch fingerlings bred from adults that were ‘rescued’ from a drying lower Baaka-Darling, and relocated to the Narrandera Hatchery back in 2019. Local Barkandji representatives, school students, collaborating with landowners, TO’s and local community representatives were invited to the re-stocking events at Pooncarie and Menindee (December 2020 and March 2021). Silver perch fingerlings are expected to be restocked back in to the Lower Baaka-Darling later inn 2021.

Barkandji River Rangers Water Quality Monitoring – We are working with the Menindee-based Barkandji River Rangers to monitor water quality (particularly risk of hypoxia) as inflows reach Menindee through 2021. The rangers will then assist with monitoring water quality downstream of Menindee during subsequent releases to the Lower Baaka-Darling, to manage potential risks to fish.

Environmental fish flow delivery and monitoring in the Lower Darling in spring-summer 2020/21 and now again for later in 2021. Our efforts aim to ensure interested community members are engaged in the planning of environmental flows to improve stakeholder understanding of environmental objectives and outcomes. In doing so we hope to also consider social or cultural concerns regarding environmental flow deliveries.

Contribution to development and planning for a potential Menindee Hatchery. We provide ongoing support and technical advice to the steering committee exploring opportunities for a fish hatchery or grow out facility in Menindee.

Fish in schools program – we have secured aquariums for Menindee/Pooncarie primary schools, and awaiting native Rainbowfish to house in them which the students will nurture.

Fisheries have conducted several rounds of community sampling within the Lower Baaka-Darling including the Menindee Weir pool. The primary objectives of this sampling are to document the status of the remnant fish populations, and; track any recovery in subsequent years. Preliminary analyses indicate a positive short-term change in the fish community after the fish death events as flows returned to the region.

Water quality monitoring through recent hypoxic blackwater events was conducted by Menindee and LDBR locals, which has informed real time management of inflows to the Menindee Lakes, and in turn, minimised risks to native fish.

Fish flow outcomes to date:
- Researchers from NSW Fisheries are reporting good survival to date by Murray cod spawned in spring 2021, on the back of good spawning and recruitment the year before (spring 2020). This is great as natural breeding is by far the most effective way to recover Murray cod stocks in flowing rivers.
- Strong numbers of Golden perch juveniles ranging from several months to 2 years old continue to develop in the Menindee lakes. These are the result of spawning events in the northern catchments, with young transported to the Menindee lakes “nursery habitats” in the ongoing high flows. Many of these juveniles are already moving back into the darling and then dispersing upstream to the Northern Murray Darling Basin, while thousands more are dispersing downstream via the Lower Darling River and the Great Darling anabranch. It is expected these fish will make an important contribution to Golden perch populations in the Murray River.

Fish Community Monitoring report (August 2023)

Varied responses were observed in species abundances in the study reaches, attributed to the various life-history traits and reproductive strategies of native fish.

The abundance of some native fish species in the LDBR has declined (in comparison to data collected since 2019) following the fish deaths events of early 2023.

Murray Cod and Golden Perch abundance has declined in comparison to previous data collected since 2019.

There were consecutive years of Murray Cod spawning in the LDBR between 2020-2021 on the back of water for the environment delivery.

Carp were the most abundant species caught during the 2023 sampling.

The results presented a fish community in continued stress. This is despite earlier demonstrated recovery of native fish from 2020-2022, driven by natural flows and deliveries of water for the environment to the LDBR.
Sustained and holistic management actions are needed for native fish protection and recovery, with continued monitoring guiding and tracking the effectiveness of these actions in the region.
With appropriate flow regimes, native fish communities will gradually recover, although catastrophic events such as fish kills related to lack of flow or hypoxic blackwater will hinder, and potentially undermine this recovery. Being long-lived, recovery of local populations of Murray Cod, Golden Perch and Silver Perch will take time.

Source: Fish kills in NSW – NSW DPI
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View the full report (PDF)

Working with community:

There will be a number of activities with key stakeholders relationships in the Lower Darling region to provide on-ground coordination and information sharing across fisheries-related activities:

Trackers are being used with 300 Golden Perch in the lower Darling-Baaka. Credit: NSW DPI.

Iain provides regular updates to local stakeholders including landholders. In his 1st April 2022 update on fish recovery and monitoring, in collaboration with DPI Environment, Energy and Science, he discussed a range of issues related to flow, including efforts to track Golden perch.

Purple-spotted gudgeon are native to the Murray-Darling Basin. Unfortunately, they are no longer found in the Lower Darling-Baaka River. Students from Pooncarie Public School are caring for a small school of Purple-spotted gudgeon in this tank to build awareness in their community around the importance of healthy rivers. Another tank is also located at BMEET – Barkindji Wiimpatya Murra Centre.

Pooncarrie School custodians of Purple-spotted gudgeon. Credit: Iain Ellis.

Freshwater dreaming - catfish. By Sam Assan

A “Fish, Flows and Cultural outcomes for the Lower Darling River “program will also be established so that Aboriginal voices are heard in water management activities and decision making. This will involve working with local Barkindji representatives so that they can inform future water management activities and decision making. This program is intended to align with the development of a “Healthy Country Program” by the Barkandji Native Title Group Aboriginal Corporation. Read the paper they produced here.

Iain presented at the Mildura Thinking Fish Forum in February 2022. This OzFish run event was designed to educate and inspire local community members and organisations to participate in local restoration efforts, benefitting waterways across the Mallee region. Iain spoke about the fundamental role flow plays in supporting the survival, movement, and breeding of native fish.

Iain Ellis presenting at the Mildura Thinking Fish Forum February 2022. Credit: NSW DPI.

Juvenile Murray cod June 2021. Photo credit: NSW DPI.

Iain ran two webinars in November 2021 with the first providing an update on native fish recovery in the reach and the second discussing how flows are planned for native fish in the Lower Darling-Baaka. In the second webinar Iain was joined by Richard Mintern and Ivor Stuart.
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Learn more and view the webinar recordings

Iain had an information stand in conjunction with the MDBA and DPI Fisheries Fish Care at the Pooncarie “Ballads on the Baaka” (in March 2021). May have even played a few songs!

Iain Ellis performs for "Ballads on the Baaka." Photo credit: Iain Ellis.

Iain Ellis at the Menindee information session. Photo credit: NSW DPI

A community workshop was held in Menindee in late November 2019 to kick off on-ground engagement. It is hoped that more events like this one will provide a channel for more effective public engagement and local knowledge to be incorporated into research activities. It will also assist researchers and managers to dispel misinformation associated with particular topics and addressing wider community issues/concerns.

Training in the use of monitoring equipment and data collection through photo-point monitoring will be provided so that community members can create photo point time series, or use photo diaries to document changes in their river, ideally pre and post drought recovery. Water quality units will also be made available for use by community members so that water quality data relating to assessing the effectiveness of aeration units Fisheries and the MDBA have installed in 2019-20 can be gathered.

Adding water into the river via the Jamesville pump. Photo credit: NSW DPI