A dry Darling-Baaka River in early 2019.
Iain Ellis

In the summer of 2018-19, after two years of low flows in the lower Darling Baaka River in western New South Wales, a series of three mass fish kills occurred near Menindee, resulting in the deaths of millions of native fish. The size of the fish kills was unprecedented, with millions of native Bony herring perishing, and thousands of culturally and recreationally important Golden perch, Silver perch and Murray cod also dying.  Thousands more died throughout the rest of 2019 as refuge pools along the Lower Darling Baaka dried up.

Post-fish kill assessments suggested the Menindee fish kills were the result of a series of factors relating to a lack of flow. Prolonged low-no flow periods in the Darling Baaka River during summer 2018/19 led to the weir pool at Menindee becoming thermally stratified (a warmer surface layer of water sits above a cooler, deeper layer in which dissolved oxygen becomes depleted). The summer heatwave was interrupted several times by sudden cool weather changes, which resulted in the deeper water layer mixing with the surface layer, causing a sudden drop in oxygen which killed fish.  

These studies of the impacts of fish kills are important, but they tend to focus on the ecological and economic impacts,  generally overlooking the cultural and community impacts. To address this, I led a study in 2021 along with a team of researchers and community representatives, to document the impacts of the 2019 Menindee fish kills on local Indigenous people and non-Indigenous communities.  We found a sense of loss, despair and helplessness in the community resulting from the fish deaths, as well as frustration towards water management and policy in the Murray Darling Basin.    Our recommendation going forward is that the environmental, social and economic elements of fish kills must not be considered as separately, but inter-dependently.

Impact on First Nations People

Baakandji people rallying for the health of the Darling Baaka at Wilcannia. Source: Sofie Wainwright.

Aboriginal communities have lived in the lower Darling Baaka region for over 45,000 thousand years. The word Barkandji means “belonging to the Baaka River”. For millennia, the Darling Baaka River was the center of resources for the Baakandji people, providing food, water, resources and medicine. Fish from the river provided a key source of sustenance in a harsh semi-arid region, hence fish and fishing practices are embedded within the Baakandji’s cultural identity. Today, fish from the river are a relatively cheap source of good quality protein and fish oil (used in traditional medicines) for some Aboriginal communities along the Baaka.

For the Barkandji, fish are much more than just a resource. Some native fish species are family totems, while the Murray cod is known as the creator of the river and an ancestor to the Barkandji people. Baakandji elder Badga Bates explains how the river and its health are important for the community and reinforce indigenous people’s connection to country.  

When the river is healthy, everything flows and Baakandji people are happy. However, when the river is sick, the Baakandji people are sick both physically and socially. Crime rates, family violence and mental health issues rise when the Baaka doesn’t flow” (Badga Bates)

Large Murray cod that perished near Menindee on the lower Darling Baaka River in the summer of 2018-19. Source: P. Heath, DPI Fisheries.
Masses of bony bream and herring were found in the Darling Baaka following the 2019 fish kills. Source: G. McCrabb.
Perished native fish found at the Menindee Boat Ramp after the fish kills. Source: Iain Ellis.
Dead Murray cod found on the banks of the Darling Baaka. Source: Wayne Smith.

Impact on non-Indigenous communities

Non-Indigenous communities on the Darling Baaka River were also affected by the death of millions of native fish. From an economic perspective, native fish and recreational fishing has been estimated to contribute in the order of $1.3 billion annually to the Murray-Darling Basin. Fishing based tourism is vital to the towns of Menindee and Pooncarie.  As explained by Josh Sheard, former Pooncarie publican:

when there was no water… the tourists didn’t come. Fishing stopped… [but] as soon as the water returned, so did the tourists”.

Beyond the economic impacts of the fish kills, observing the deaths of millions of native fish was traumatic for many locals. Repeat kills only added to the heartbreak – and a feeling of powerlessness. Some people made efforts to preserve fish by trying to aerate water with pumps (in collaboration with State and Commonwealth Agencies) or boat motors to little avail. Aerators installed by NSW Fisheries and local community members ran day and night throughout much of 2019 to maintain oxygen levels in a handful of refuge pools. Volunteers assisted NSW DPI Fisheries in rescuing and relocating stranded fish to captive maintenance facilities or sections of river that retained suitable water quality for fish survival. While these admirable efforts preserved some local fish, it was small consolation to many who experienced the fish kills first hand.

NSW Fisheries Manager Iain Ellis and Lower Darling farmer Wayne Smith (& son Dusty) relocating a stranded Murray cod to more secure water. Source: P. Heath.

The fish kills at Menindee and the conditions that contributed to them also impacted the town’s water supply at Menindee. Even after water from the river was treated, locals remember it retaining “foul odours”, and some people believe skin conditions were linked to the poor-quality water. Fresh drinking water was delivered by trucks into the region for months at the expense of local councils and volunteer organizations.

So what can be done to prevent mass fish kills?

Ultimately, flows from the northern Murray Darling Basin were the only thing that would have prevented ongoing deaths of fish, as refuge pools along the Lower Darling Baaka dried one by one throughout 2019.

Finally, in early 2020, heavy rains in the northern catchments resulted in a return of flows to the Darling Baaka, filling the Menindee Lakes again. The nutrient rich flows brought life back to the Menindee Lakes and carried fish to the Lower Darling-Baaka (including millions of juvenile Golden perch spawned in response to the elevated river flows in the northern Murray Darling Basin).

The Darling-Baaka starting to flow again in March 2020, a couple of kilometres downstream of Menindee. Source: Iain Ellis.

The return of flow provided opportunities for agencies and community to work together on a number of restoration activities supported by the Native Fish Recovery Strategy. These include:

  • Environmental flows being delivered to assist with the recovery of native fish in the Lower Darling Baaka, and dispersal of juvenile fish south to the Murray River. Local community stakeholders provided input into the planning of these flows.  
  • Mapping of habitat and deeper refuge holes where conservation and recovery activities can be focused.
  • Restocking of Murray cod fingerlings to the lower Darling Baaka River (bred from those rescued in 2019).  
  • Monitoring of fish communities in the Lower Darling Baaka and Menindee Lakes with assistance from local Barkandji River Rangers.
  • Water quality monitoring conducted by local stakeholders including the Barkandji Rangers.
  • Progress towards improved fish passage in the Lower Darling-Baaka.

Ultimately, however, native fish rely on flow. In the case of the lower Darling-Baaka, this comes from the northern Murray Darling Basin. An Independent Panel appointed by the Australian Government to assess the Menindee Fish kills found that contributing factors included climatic conditions hydrology and water management. The panel recommended that Murray-Darling Basin governments commit to protecting low flows in drier conditions, as well as the first flow down the river system after significant rainfall as this is very important for connectivity in the river.  Barriers to fish movement and refining operational procedures at the Menindee Lakes were also recommended actions.  The panel also wanted  increased investment in research (in rivers and climate change impacts), monitoring, emergency warning and response capability, as well as collaboration with local communities.

Ongoing research is critical. Mallen-Cooper and Zampatti recently published work that highlights the near perennial (continuous) flow of the Barwon Darling system prior to river regulation and development –  which should be taken into account in water planning.

Whilst Lower Darling Baaka Communities understand climate and drought will result in drier periods, they also recognize that occasional short low or cease to flow events are very different to the protracted dry river experienced throughout 2019. The flora and fauna of inland semi-arid rivers are tough – they have adapted over millennia to withstand intermittent periods of low flow (or cease to flow), but even they have limits to survival in a highly modified river system facing ongoing climate change.  

Lower Darling communities are united in their advocacy for improved water management to prevent repeats of the Menindee Fish kills. Ideally, by learning from the millions of deaths seen in 2019 and their impacts on people connected to the river, such large catastrophic fish kills can be avoided in future.  

More information:

Featured image: A dry Darling Baaka in early 2019. Source: Iain Ellis.

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