Restoring Noosa River’s Oyster ecosystems
PROJECT UPDATE: Designs for proposed oyster ecosystem restoration sites have been released. READ THE FULL UPDATE >>
Noosa has a reputation as one of Australia’s most desirable holiday and living destinations. It’s known for its expansive beaches and colourful bays, but not for its once abundant oyster ecosystems.
Over 100 years ago, oyster beds were common throughout the Noosa estuary. There is still evidence of those beds today in a local feature the ‘Lions of Tewantin’, which are aboriginal shell middens, (structures formed from discarded shells from the seafood eaten by the aborigines) several metres high.
Unfortunately, by the early 1900s, Noosa’s oyster beds had become functionally extinct through over-harvesting and dredging. This drastic habitat change contributed to declines in local fish stocks such as snapper, bream and mullet.
The story is no different for the southern coast of Australia and globally, where 85% of oyster-dominated shellfish ecosystems have become extinct as a result of overharvesting, disease, and poor water quality.
Oyster beds once abundant in Queensland
Slide the arrow in the image below to see oyster beds before and after they were overexploited.
Left photo: taken in 1906, of natural oyster bed at Toorbul Point, Queensland. These reefs were a structurally complex habitat that provide feeding opportunities, shelter and spawning areas for fish in estuaries. Oyster beds can also slow erosion processes and can improve water quality.
Right photo: Toorbul Point over 100 years later. There is a very high number of dead oysters and a lack of oyster recruitment. Abundant algal growth traps sediment, giving the rocks a dirty appearance.
Returning oyster ecosystems to the Noosa River
The Nature Conservancy, Noosa Shire Council and the Noosa community together with support from the Thomas Foundation and Australian Marine Conservation Society are working together to rebuild oyster beds and reefs in the Noosa River. The project will improve habitat for fish and marine life, filter the water, and help to keep Noosa’s much-loved estuary clean and clear for locals and visitors to enjoy. The project will help to improve Noosa’s reputation as a destination of choice, enhancing nature-based tourism and outdoor lifestyle living.
With support from our partners, we’re planning to double the size of the planned reef from 1 to 2 hectares. We’ve also signed formal partnerships with three local groups to help deliver the community-led Noosa oyster gardening project and engagement activities in secondary and junior schools across the Noosa catchment.
An important goal of the project is to enhance Noosa’s fishing experiences. Rock oysters form complex natural structures that provide food-rich habitat for a diversity of marine plants, invertebrates and fish species. For estuarine fishes, oyster beds provide two key functions:
- They provide structurally complex habitat that fish use for resting, seeking refuge from predators and spawning; and
- They provide a diverse range of food resources, including planktonic prey, smaller fishes and the oysters themselves, which occur in higher concentration in and around the reefs.
Benefits of restoring shellfish ecosystems
Bringing back Australia’s most threatened marine ecosystem, these native shellfish reefs, also bring back a wealth of benefits for people and nature. This includes:
- improved local fish populations as beds and reefs act as fish nurseries
- better water clarity due to the filtration power of shellfish
- extra feeding habitat for threatened migratory shorebirds
- an overall increase in biodiversity
Shellfish ecosystem restoration across Australia
This project is part of our bigger program to rebuild shellfish ecosystems across southern Australia. See our other shellfish ecosystem restoration projects: