More than one-third (37%) of our native freshwater fish species are at risk of extinction, including 35 species not yet listed as threatened. Dozens of our native freshwater species could become extinct before children born today even finish high school (Lintermans et al., 2024).  

A recent study led by Associate Professor Mark Lintermans, Senior Research Fellow in Freshwater Ecology at the University of Canberra, along with a team of 52 freshwater fish experts, highlights the alarming state of Australia’s freshwater native fish. These findings were also explored in a recent Conversation article, “Troubled waters: how to stop Australia’s freshwater fish species from going extinct,” which offers further insights into the study’s implications.

While some efforts to protect them are underway, there’s a clear-cut gap between the threats driving species decline and what needs to be done. Without urgent intervention, Australia could lose some of its most unique aquatic species forever.

To better understand what's causing these declines and what can be done we spoke with Dr. Nick Whiterod, freshwater ecologist and Science Program Manager at the Coorong, Lower Lakes and Murray Mouth Research Centre, and one of the study’s contributing authors.

Why are our native fish in trouble?

According to the study, invasive species are the single biggest threat to native freshwater fish, impacting 90% of threatened species.

Dr. Whiterod says to conserve threatened freshwater fish we must address the threat posed by invasive species.

The second biggest threat was found to be modified stream flows and ecosystems (82%), followed by climate change and extreme weather (54%).

Conservation policy gaps in Australia

The study highlights significant gaps in Australia's freshwater fish conservation policies, which fail to adequately protect many freshwater fish species.

Dr. Whiterod identified three major issues that must be addressed to improve freshwater fish conservation:

• Underrepresentation of Threatened Species: The Environment Protection and Biodiversity Conservation (EPBC) Act doesn’t include many species that clearly meet the criteria for protection. The study identified 35 additional species that should be urgently assessed for listing.

• No National Action Plan for Freshwater Fish: Without coordinated action, conservation efforts remain fragmented and under-resourced. We need an overarching national strategy to achieve coordinated responses to many threats and to implement strategic conservation actions.

• Lack of Recognition for Key Threatening Processes: There are currently no invasive species listed as a Key Threatening Process under the EPBC Act, despite their widespread and devastating impact.

Success stories offer hope

We also asked Dr. Whiterod about his favourite success story in freshwater fish conservation. He highlighted the recovery of the southern pygmy perch in the Lower Lakes of the Murray-Darling Basin.

After being wiped out from the region in 2008 during the Millennium Drought, a dedicated group of not-for-profit organisations, universities, government agencies and community members decided to act. Together, they rescued and bred the species in safe locations, in turn enabling reintroductions into its former habitats around the lakes as favourable conditions returned. Fast forward to the present, and a species that was on the brink of extinction has reestablished in the region.

He describes this as a glimpse of what’s possible when we acknowledge the seriousness of the challenge and take collective action.

The bigger picture: why this matters

Dr. Whiterod emphasised that the decline of freshwater fish is not just an isolated concern, they are indicators of entire river health.

Dr. Whiterod explained, “Healthy rivers support diverse and abundant fish populations, but degraded systems lead to declines.”

He also stressed that the loss of a single species might seem minor, but it can have cascading effects on entire ecosystems. Individual species each play critical roles in maintaining habitat structure, nutrient cycling, and food webs. If culturally or ecologically significant species disappear, it not only can weaken ecosystem resilience but also impact First Nations communities' connections to Country.

Human activities, including water extraction, dam construction, pollution, and habitat destruction, have driven these declines. But as Dr. Whiterod highlighted, the same human intervention can reverse the damage. Conservation strategies like habitat restoration, improved water management, and invasive species control can bring native fish populations back from the brink.

Making a difference: what can you and I do?

Australia’s native fish are facing an uphill battle, but we all have a role to play in ensuring their survival. Dr. Whiterod stressed that awareness is the key and that our actions, both big and small, influence freshwater fish populations.  

Dr. Whiterod highlighted that the most effective way to make a difference is to understand what’s happening in your local waterway, recognise the threats, and work together to minimise our impact.  

“The keys are really to better understand what occurs in your area as well as the threats and work with others to minimise the impact that you may be having on threatened species.”  

By becoming more aware of the challenges facing our native fish, we can support local conservation efforts, help reduce the impact of invasive species, and advocate for better policies. Whether it’s through habitat restoration projects, responsible fishing practices, or simply spreading the word, small actions can lead to big change.

Protecting our freshwater ecosystems is a shared responsibility, one that requires all of us to step up before it’s too late.

With the right policies, funding, and community engagement, we can protect these species for future generations. The time to act is now.

Resources

Read the full study here

Read The Conversation article here