The Lungfish Habitat Rehabilitation project is working to ensure the long-term survival of the Australian lungfish by re-establishing submerged aquatic plants in the Brisbane River between Wivenhoe Dam and the Mount Crosby Water Treatment Plant. The plantings will also improve river health and water quality of Brisbane’s major source of drinking water.
This habitat rehabilitation program forms part of a broader strategy that Seqwater has developed to ensure the survival of the Australian lungfish in South East Queensland rivers.
Stable populations of Australian lungfish are only found in three river systems in the world so protecting their habitat in those rivers is critical to their survival.
About the project
- Restoring lungfish breeding habitats in the Brisbane River.
- Improving river health and water quality.
- Increasing knowledge of riparian restoration and lungfish habitat in the Brisbane River system.
Why this project is important
The Australian lungfish is a prehistoric species that first appeared in the fossil record 380 million years ago, well before dinosaurs. The Australian lungfish is the oldest known living vertebrate, remaining unchanged from its current form for over 100 million years, and is listed as a vulnerable species under the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act 1999.
Several factors are putting pressure on lungfish populations, including loss of breeding habitat, barriers that block access to, or inundate breeding habitats, egg predation by invasive fish, and extreme weather conditions.
While the numbers of Australian lungfish in the Brisbane River remain good, their breeding opportunities have been impacted by significant floods. The aquatic plants they lay their eggs in were ripped out of large areas of the riverbed and have not recovered.
Surveys conducted by Seqwater have confirmed very few juvenile lungfish are found in the river and without intervention, the reduced breeding opportunities may start to affect the population in the Brisbane River.
On ground action
The innovative program is re-establishing submerged aquatic plants (macrophytes) vital for lungfish breeding that were damaged in the significant floods of 2011 and 2013. The program involves re-establishing the river’s macrophytes – that have been grown in plant nurseries – on tiles of biodegradable coir matting, then transplanting them into the riverbed.
The coir planting tiles are kept in place using a few large rocks as well as stakes made from corn starch which break down after a few years. To transplant the tiles, the team wades out into knee deep water, digs a shallow hole in the riverbed, places the tile in the hole and secures it to the riverbed using the stakes and covers them in a layer of sand and rocks.
The tiles must be planted in shallow water (less than one metre), as the macrophytes need sunlight to grow, and these areas of shallow gently flowing water are the ideal conditions for lungfish to lay eggs once the macrophytes establish.
Griffith University is conducting research to evaluate the effects of different water depths, river speed and riverbed material on the success of the planting program
The program aims to plant over 100 square meters of macrophytes in total, which will grow and expand to new areas of the river over time.
Healthy Land and Water and Seqwater plan to publish the findings from the program to share the information with counterparts working on riparian restoration and lungfish projects in the Mary and Burnett river systems.
This project is delivered in partnership with Seqwater. Other key project collaborators include Griffith University and the Australian New Guinea Fish Association (ANGFA).
Not only is the program restoring lungfish breeding habitats in the Brisbane River, but it is also improving river health and water quality of Brisbane’s major source of drinking water.
As a result of the program, there has been an increase in knowledge of macrophyte restoration techniques and lungfish habitat status. This information can be used to respond quickly if a large flood event causes similar damage in the future, as well as assist future projects in the other two locations Australian lungfish are found, the Mary and Burnett river systems.
Macrophytes grown in plant nurseries are transplanted into the riverbed on tiles of biodegradable coir matting.
To transplant the tiles, the team wades out into knee deep water, digs a shallow hole in the riverbed, places the tile in the hole and secures it to the riverbed using the stakes and covers them in a layer of sand and rocks.