This is a great story of major effort underway to revive a once apex predator that helped regulate the river’s ecosystem. The Brisbane River Cod vanished from the waters nearly a century ago, leaving a gap in the natural food chain.

Healthy Land & Water has been on the case, recently releasing some 12,500 Mary River Cod into the Brisbane River. Read on to find out why this is so important and check out our great photo spread.

In early December 2024, approximately 12,500 Mary River Cod were released into the Brisbane River’s waters – not just any fish, but the closest living relative to the Brisbane River Cod, an apex predator that disappeared from these waters nearly a century ago.

Think of it as fixing a missing piece in nature’s puzzle. The original Brisbane River Cod disappeared between the 1920s and the 1940s, leaving the river’s ecosystem off-balance.

Apex predators like the Brisbane River Cod play a vital role in maintaining the health of river ecosystems. They regulate populations of smaller fish, keep the food chain balanced, and help preserve biodiversity.

The cod's absence has created an ecological gap, which the Brisbane River Cod Recovery Project seeks to fill by reintroducing a closely related species, the Mary River Cod.

This year’s release event, coordinated by Somerset & Wivenhoe Fish Stocking Association with support from Resilient Rivers, continues to promote cod populations in Warrill Creek, the Mid Brisbane and Bremer Rivers. This release event is a significant milestone in this project, aiming to enhance biodiversity and ecosystem balance.

Healthy Land & Water’s project team members Josh McDonald-Davis, Margie Dickson and Hannah Sherlock were there to participate in the release and witness these young cod, called fingerlings, take their first swim in their new home.

One cod to rule them all – the ecological importance of the Brisbane River Cod

		Ecosystem rebalance Fish habitat enhancement as a co-benefit at the DRFA Pine Mountain and Borallon sites.
		Restoring vegetation Revegetation of the riparian corridor and enhancement of instream habitats will be integrated into riverine sites.
		Water improvements Riverine works to improve water quality.

The Brisbane River was once abundant with Brisbane River Cod (Maccullochella sp.), known as Bumgur to the Jinibara people.

The Brisbane River Cod was the top apex predator before going extinct, leaving behind an ecological and food chain void that rippled through the entire river system, affecting the balance of local fish populations and habitats.

Think of the Mary River Cod (Maccullochella mariensis)as nature’s closest backup plan. Scientists identified it as the closest suspected genetic makeup to the lost Brisbane River Cod, making it the ideal candidate to step into those fins.

This is where the Brisbane River Cod Recovery Project comes in. Run by the Somerset-Wivenhoe Fish Stockers Association (SWFSA), the project is “re-establishing the self-sustaining presence of an apex predator Maccullochella sp. cod species into the Brisbane River catchment and tributaries” with restocking efforts aiming to rebalance ecosystems with the re-introduction of this apex fish.

Healthy Land & Water team members attended the event in December 2024, releasing Mary River Cod fingerlings into the Brisbane River as part of the Brisbane River Cod Recovery Project.

There ain’t no party like a cod release party – a step toward ecological restoration

The SWFSA team isn’t working alone. Their team is the driving force behind restocking these native fish throughout the Brisbane Valley’s waterways. This isn’t just about numbers – it’s about creating a self-sustaining population that can thrive across South East Queensland’s river system.

At this cod release event, the Healthy Land & Water team supported the release of Mary River Cod fingerlings into the Bremer River, Warrill Creek, Reynolds Creek and Bundamba Creek.

Fingerlings were also released into the lower mid-Brisbane River where Healthy Land & Water are implementing important environmental resilience work as part of the Riverine Flood Recovery Project, with assistance provided through the jointly funded Commonwealth-State Disaster Recovery Funding Arrangements.

The numbers tell an impressive story: since 2020, approximately 86,000 Mary River Cod fingerlings have found new homes in the Brisbane River and its tributaries. Add to that the 14,000 cod released in late November 2024 and you have got a serious restoration effort underway.

Crucial support for this important project

Fingerlings being released into the Bremer River, Warrill Creek, Reynolds Creek, Bundamba Creek & (lower) mid-Brisbane River.

Healthy Land & Water is bringing its expertise to the Brisbane River Cod Recovery Project through several key initiatives. These include:

• Fish habitat co-benefit offered under DRFA Pine Mountain and Borallon sites.
• Revegetating riparian corridors and enhancing instream habitats at riverine sites.
• Implementing riverine works to improve water quality.

The Brisbane River Cod Recovery Project is a vital initiative aimed at restoring the ecological balance and biodiversity of South East Queensland’s waterways. As Mary River Cod populations grow with each release, the project aims to restore the health of the rivers and support the recovery of threatened freshwater fish species.

Acknowledgements

This project is supported by:

• Australian Government
• Queensland Government
• Ipswich City Council
• CleanCo Queensland
• Resilient Rivers / Council of Mayors South East Queensland
• Scenic Rim Regional Council
• Cummins / Global Giving
• Somerset Regional Council

With assistance being provided through the jointly funded Commonwealth-State Disaster Recovery Funding Arrangements.