Mary River Cod log trials kick off in the Brisbane River
A new series of riverside hotels has opened in Pine Mountain, Ipswich, but this hotel chain won’t be welcoming guests of the human kind anytime soon. 25 cod log hotels have been installed underwater in the Brisbane River to support the recovery of the Mary River Cod, an apex predator introduced to replace the extinct Brisbane River Cod which disappeared from local waters over a century ago. These purpose-built shelters, made from disused logs that were otherwise heading to the chipper, have been installed to provide additional breeding habitats for this endangered species, aiming to boost its population. This follows recent efforts by Healthy Land & Water, supporting the release of Mary River Cod fingerlings into the Brisbane River.
Read on to learn more about the importance of the cod log hotels and the inspiration behind the recent installation at Pine Mountain.
Vital works after the 2022 floods
Our project site at Pine Mountain is currently undergoing vital on-ground recovery works following significant damage from flooding in 2022, which stripped vegetation and caused significant damage to aquatic habitats.
Pine Mountain Reach erosion of the inset floodplain, channel shortcutting, and vegetation stripping..
As part of the Riverine Flood Resilience Project, this site was identified as a priority location for restoration to support the long-term health and resilience of the Brisbane River.
Key works already underway include:
- Pile field construction and revegetation.
- Rehabilitation and restoration of flood-affected environments to maintain healthy ecosystems and other environmental values.
- Improved resilience for future disaster events.
Important flood resilience works are underway to help prevent future disaster events in the Brisbane River.
A key focus of this project is to improve the resilience of the reach against future flooding events by reducing fluvial scour across the inset floodplain. This is expected to improve water quality and limit the widening of the chute cutoff, reducing the intensity of downstream pressures. Co-benefits include the improvement of aquatic habitat quality, enhancing biodiversity along this section of the Brisbane River.
This reach holds significant ecological value, thanks to riparian vegetation that provides shade, as well as slow-flowing pools that offer stable water, food sources, and potentially ideal breeding conditions for native species including the Queensland lungfish and the Mary River Cod.
Historically, the presence of the Mary River Cod populations sustained through translocation works in this area has been limited due, in part, to river barriers and the impact of past flooding events, which stripped vegetation and disrupted habitats. Our civil construction work aims to stabilise the streambank, making it more resilient to erosion during floods or strong flows. This will help protect and restore critical habitats for fish and other aquatic life.
Nature-based opportunities and collaboration at work
While the installation of underwater cod hotels is a first for Healthy Land & Water in South East Queensland (SEQ), this method is currently under successful trial in the Burnett Mary region.
This initiative is a joint project between Griffith University and two Natural Resource Management (NRM) groups – the Mary River Catchment Coordinating Committee (MRCCC) and the Burnett Mary Regional Group (BMRG).
Nathaniel Larsen, project officer at MRCCC has been fundamental in making this trial a reality in SEQ by sharing lessons learned with our project teams, design specifications and installation methods, highlighting the power of collaboration and knowledge sharing in the NRM sector.
To bring this project to life in SEQ, it made use of a timely opportunity to support habitat growth when a sustainably minded arborist offered large, hollowed-out timber logs that were destined for the chipper.
The cod logs are being given a second life.
Creating a healthy ecosystem
The newly installed cod logs are helping to create a safe and suitable spawning habitat for the endangered Mary River Cod. These specially placed logs act like underwater hotels – offering shelter and protection for eggs, keeping them safe from predators, and giving this species a better chance to thrive.
The Healthy Land & Water team recently hit the waters to install these cod logs, with generous support from the volunteers at Somerset Wivenhoe Fish Stocking Association, a not-for-profit organisation who are instrumental in restocking native fish in Queensland waterways.
This nature-based solution involved rolling extremely heavy (up to 100kg) logs into the Brisbane River, using floats to guide them downstream and securing them in place.
And it’s not just the Mary River Cod moving in. These log hotels will also provide habitat for a variety of native aquatic species, including fish, eels, turtles, and even water dragons.
The project team and volunteers installing the cod logs.
Cod log hotel – now open for bookings
The project team and volunteers installing the cod logs.
The cod log hotels are now officially open! The incredible team of volunteers at Somerset Wivenhoe Fish Stocking Association will look after the ongoing maintenance and monitoring of the underwater habitats to track how the cod are enjoying their stay.
We’re confident it’s going to be a five-star experience – both for the cod and the future of our river ecosystems.
Project collaboratorsThis project is supported by Healthy Land & Water, with assistance provided through the jointly funded Commonwealth-state Disaster Recovery Funding Arrangements (DRFA). Partners include the Resilient Rivers Initiative, ICC, Port of Brisbane and Lockyer Valley Regional Council. Thank you to the landholder for allowing us access via their property to complete these works, the team at MRCCC for sharing their learnings and thank you to Fitzy and his team at Somerset Wivenhoe Fish Stocking Association for bringing the muscle (and good vibes!) to install day. |
