1 million mussels ready to be deployed in the Swan-Canning Estuary to revive shellfish reefs

JOINT RELEASE: The Nature Conservancy (TNC) Australia’s Swan-Canning Estuary shellfish reef restoration project is entering an exciting new stage, with one million mussels about to be seeded across 24 pilot reefs in June.

“It’s an exciting time for us and an important day for our shellfish reefs,” says Andrew Bossie, Project Coordinator for TNC Australia’s Oceans Program.

“This week more than one million live, locally-grown native Blue Mussels will be deployed across our pilot reefs built between Point Walter (Bicton) and Point Dundas (Applecross). The information they provide will help us determine the best sites for building our full-scale reef, which is planned for mid to late 2022.” 

Minderoo Foundation recently released the second tranche of a $2 million pledge to help support the estuary's health, bringing the total funds for this restoration project to about $5 million. The project has received additional support from the Department of Biodiversity, Conservation and Attractions, the Australian Government as well as Jock Clough, Adrian & Michela Fini, Austral Fisheries, Gavin Bunning, The McCusker Foundation, Major Holdings Pty Ltd, and Michael & Margrete Chaney. The project was originally kick started thanks to support of more than $1.2 million from Lotterywest.

Mussel reefs will boost the health of the estuary by filtering millions of litres of water, providing habitat for many different species and increasing fish productivity. It is estimated that one hectare of fully restored and fully functioning reef can filter about 2.7 billion litres of estuary water a year.

“The Swan and Canning rivers have incredible cultural and recreational significance for the Perth and Fremantle communities,” said Tony Worby, CEO of Minderoo Foundation’s Flourishing Oceans initiative.

“We need to ensure the rivers are kept clean and healthy. They play a big part in the lives of many West Australians and are a critical component of our state’s environmental ecosystem.”

“Shellfish reefs and then later extensive shell banks once covered large parts of the estuary, but they have largely disappeared through changes in the estuarine environment and dredging. Rebuilding these reefs, and adapting the shellfish species to suit our changing conditions, will help bring back vital functions to keep our estuary healthy and more resilient to stress,” says Andrew Bossie.

The pilot reefs, the limestone substrate for which was built in June 2020, have already shown some very positive signs and lots of life, including many settling organisms like scallops, sea squirts, fan worms and macroalgae. A high number and diversity of fish as well as crabs have also taken up residence around the rocky reefs.

The Swan-Canning Estuary is one of 13 sites identified for reef restoration under Reef Builder, a partnership between the Australian Government and TNC to bring shellfish reefs back from the brink of extinction and support the economic recovery of communities impacted by bushfires and COVID-19 restrictions. This Project is part of TNC’s larger national shellfish restoration program that aims to rebuild 60 shellfish ecosystems across Australia. If achieved, Australia will be the first nation in the world to have recovered a critically endangered marine ecosystem.