Gamay is one of Australia’s most developed estuaries . . .

housing major air and seaport infrastructure and fringed by dense industrial and residential areas.

Despite this large human influence, the bay maintains a diverse marine ecosystem, popular with SCUBA divers and naturalists.

However, sensitive habitats, like Posidonia meadows, have declined dramatically and need a helping hand.

Posidonia needs plenty of light and stable sediments to grow.

Coastal development can reduce the light that passes through the water, either by suspending sediments in the water column during constructing or adding structures that create shade.

Often hydrodynamics are changed when structures are added to the coast, causing sediments to move and erode seagrass meadows or even smother them.

Development activities like dredging have been widespread in Gamay since European settlement, and entire sections of the bay’s former seagrass meadows have now disappeared. 

All hands on deck

A creative solution to restore a precious species

Posidonia grows very slowly, so even in places where threatening processes have subsided, it doesn’t recover on its own. Collecting beach-cast fragments of Posidonia to use in restoration helps us restore meadows without damaging vulnerable populations.

This exciting solution gives community members the opportunity to assist with marine conservation in a hands-on, meaningful way, all in the name of protecting the underwater world on their doorstep. 

Collaborators

Gamay Rangers

The Gamay Rangers are an Indigenous Ranger group from Gamay, Botany Bay, based in La Perouse. They are the first Indigenous Ranger group operating in an urban area. Read about their important work here.

We are working closely with the Rangers on the ground to deliver our Posidonia restoration project. The team is highly skilled in environmental management, boating and free-diving. We are also providing two-way training opportunities, such as training in marine ecology techniques.

The Port Authority of NSW

Over more than ten years, the Port Authority of NSW has undertaken significant ecological monitoring around the Penrhyn Estuary and Foreshore Beach areas of Botany Bay, including monitoring the health and extent of local seagrass meadows.

In late 2016, Port Authority invested $3.7million to construct three groynes along Foreshore Beach to mitigate beach erosion, sediment transport and to stabilise sediments to protect and improve conditions for seagrass.

The great news is their work and investment to stabilise sediment movement on the seafloor has already seen the ecological recovery and re-establishment of Zostera and Halophila seagrasses in the area, signalling conditions may now be favourable to re-establish Posidonia.

The Port Authority of NSW is a key partner in our project in Gamay Botany Bay and are supporting the establishment of a seagrass holding pen for temporary storage of our Posidonia transplants nearby to Foreshore Beach. Initial restoration is planned for target areas near Foreshore Beach in waters managed by the Port Authority.

Operation Posidonia acknowledges the Traditional Custodians of the land & waters where we conduct our research. We recognise their continuing connection to these places, and thank them for protecting this coastline and its ecosystems for many generations. We extend these respects to Elders past and present, and extend these respects to all First Nations people.