WATCH: Seagrass shows promising recovery

Researchers from UNSW took to the water at Penrhyn Estuary, Gamay Botany Bay to assess survival and growth rates of Posidonia australis, examining how the transplanted seagrass fragments were adapting to their new environment.

“Posidonia seagrass meadows are increasingly rare in Sydney and NSW waters but incredibly important as nursery habitats for juvenile fish and endangered species such as White’s seahorse,” said Port Authority of NSW group executive, people, environment and legal, Amy Beaumont.

“It’s really encouraging to see the planted seagrass fragments establishing so well just three months after being moved from our holding tank nursery. Their progress is certainly promising.”

UNSW postdoctoral fellow and research spokesperson Dr Giulia Ferretto said the health check results are a positive sign for one of the state’s most threatened marine ecosystems.

“Seagrasses like Posidonia are crucial for supporting biodiversity, protecting coastlines from erosion, and capturing carbon,” Dr Ferretto said.

“Once damaged, Posidonia meadows rarely recover naturally, which makes this collaborative restoration work so important.”

Despite heavy rainfall in recent months, the transplanted shoots have withstood freshwater inflows better than expected. The team aims to refine scalable restoration methods and develop a genomic toolbox to strengthen resilience in the face of climate change.

The project, involving UNSW, the La Perouse Local Aboriginal Land Council (Gamay Rangers) and Port Authority of NSW, integrates traditional knowledge with marine science.

The next health check is due in two months, continuing efforts to restore a seagrass species deeply significant to the Kamaygal Traditional Owners of Botany Bay.