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Boat mooring chains have devastated 130,000 square metres of seagrass in NSW by scraping along the bottom of bays and creating “scars” that take two decades to recover.
To counter this destruction, Project Restore will trial the installation of 16 seagrass-friendly moorings – which have tethers that float above the sand - and restore meadows destroyed by dragging chains.
“It’s really a critical time because right now, there’s still enough Posidonia that we can build on and there are still some healthy meadows near Sydney, but they are declining really fast,” Verges said.
The plant can reproduce sexually but mostly expands slowly by self-cloning. It can take a year for the plant to create a new shoot.
“It’s a strategy that has served the species well. It’s been able to survive through millennia. But with the kind of stressors that we’re subjecting the species to now, through urbanisation and climate change, it may not be enough.”
Verges had restoration success in Port Stephens, where Operation Posidonia recruited a “storm squad” of citizen scientists to collect strands of washed-up seagrass that were used to restore and create new meadows.
She plans to use a similar approach to transplant seagrass from Port Hacking and Pittwater into Sydney Harbour, including at a proposed site near HMAS Penguin at Balmoral.
Project Restore will trial 16 seagrass friendly boat moorings, which have floating tethers rather than chains that drag along the sand and create seagrass “scars”.Credit: Operation Posidonia
Seagrasses provide critical habitat for fish species such as snapper in the early months of their lifecycle and secure particles in sediment, making surrounding seawater cleaner and clearer. They’re also a major carbon sequestering force.
“If you were to put in a core down through a seagrass meadow, it’s a bit like an iceberg,” Verges said. “You can actually go back in time … one metre of Posidonia [sediment] would be about 1000 years. That’s all the carbon that has accumulated throughout the millennia.”
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Project Restore will launch officially next month. Meanwhile, project manager Dr Paco Martínez-Baena is engaging with communities around the harbour to help choose sites for seascape restoration.
“They are the ones who are in the harbour all the time, fishing, snorkelling, swimming, enjoying the harbour,” he said.
“We’re really positive and really hopeful that the community is going to back us up, and we’ll be able to make it happen.”