Oyster Restoration Project

Background to the project

Picture for oyster project media release.

Some of Australia’s best scientists gathered in late 2014 to discuss possible restoration and management options for the Noosa River.

It was the first time such a holistic approach had been applied to the Noosa River, in the quest to improve the diversity of aquatic species, such as prawns, bream, mullet and crabs.

The panel of 10 scientists agreed that one of the most effective ways to improve biodiversity was to restore some of the oyster ecosystems that once dominated the Noosa River.

Check out the detailed report from the workshop.

What is an oyster ecosystem?

These ecosystems are made up of oysters, mussels, and a multitude of other creatures, offering a whole suite of ecosystem services. They work just like coral reefs as fish factories.

Oysters are incredible filter feeders. They eat by pumping large quantities of water through their body and remove algae and nutrients. This makes the water clearer and cleaner for seagrasses and other marine life. Half a hectare of oyster reefs can filter the equivalent of 36 Olympic swimming pools of water every day.

Outcome of the trials?

The Nature Conservancy conducted a preliminary scoping study in early 2015, to determine if there were still enough oyster larvae (known as spat) in the river to create new ecosystems.

The results showed good spat settlement within the estuary and the study recommended installing a number of pilot structures for further monitoring and assessment.

Noosa Council co-funded and provided in-kind support for a small-scale oyster restoration unit trial.

A University of Sunshine Coast (USC) project team identified that 15 sites were needed for the oyster restoration units, which were placed in a range of locations in the Noosa River and lakes.

These trial units were not reefs, but experimental units specifically designed to help provide answers to some key questions associated with the project. They consisted of nine coir bags filled with cleaned oyster shells, at each of the 15 sites.

USC established a biannual monitoring program, with clear monitoring methods and performance targets.

In November 2018, the first year results indicated excellent recruitment of oysters in the trial units and no negative impacts on the adjacent environments.

The oysters hadn’t yet joined together but this wasn’t expected after just 12 months. There were some signs of propeller damage to a couple of the reefs, and these were repaired.

Two months later, in January 2019, a further inspection found much more widespread damage, thought to be from propellers and anchors over the busy Christmas period, and 10 of the 14 units were removed. The remaining units continued to be monitored with a second year and final report.

As well as this monitoring, USC also undertook various other studies, including the way the way fish used the new experimental units and provided a detailed report on the outcomes.

Council and The Nature Conservancy Partnership

The Noosa River was once full of oysters and the Kabi Kabi came from all over the region to eat here. Now they are gone. In areas of the world where oyster ecosystems still occur, they are areas of high biodiversity, much more so than muddy substrates.

Years of carefully designed trials in Noosa River have indicated that a project can succeed. In recent years many countries, states and local areas have begun the process of trying to restore these habitats in recognition of this.

No organisation in the world has more expertise in this area than The Nature Conservancy. The Nature Conservancy is one of the world’s largest practical conservation organisations, working in over 70 countries, with over 400 scientists on staff and links to every major research institution in the world.

The Nature Conservancy approached Council in late 2018 to enter into a partnership, where both parties provided $1.2M each, to restore some of the lost oyster ecosystems of the Noosa River.  A partnership agreement was endorsed by Council in 2019 and a TNC project team was on the ground in early 2020.

Council endorsed a project plan in July 2020. For more details, the following reports are provided;

Council has prepared a report for the General Committee Meeting on 24 October 2022 and all Background documents (Appendixes to Report) can be found via this LINK.

Construction of the reefs has begun, and it is expected to take approximately six weeks, dependent on site conditions. The four restoration sites are at Tewantin, Goat Island and Noosa Sound East and West. Three reefs have been built at Goat Island, and three also at the Tewantin site, with works to commence shortly in Noosa Sound. Read the current Project News for more information.