Seagrass restoration trial in Leschenault estuary gains momentum

The latest seagrass restoration trial in the Leschenault Estuary is underway, with volunteers, researchers, and Indigenous rangers working together to pioneer new techniques for restoring Western Australia’s underwater habitats.

This marks the first successful collection of Halophila ovalis (paddleweed) fruit in the project, after previous attempts in January and March last year missed the ideal timing. Volunteers and researchers gathered over 190 fruits, each containing between 8-12 tiny seeds, which will now be germinated by a University of Western Australia research student before being returned to the estuary.

Unlike the larger, slow-growing Posidonia seagrass, which has been the focus of OzFish’s Seeds for Snapper project, Halophila is a fast-growing species with the potential to rapidly reestablish meadows. However, its seeds have proven trickier to work with—taking longer to drop and germinate compared to Posidonia. The team is trialling new methods to understand the best way to use these seeds in restoration efforts.

“Getting the timing right for seagrass restoration is critical,” said Steve Pursell, OzFish WA Program Manager. “We know Halophila fruits at the end of summer, but pinpointing the exact window for collection has taken some trial and error. This year, mid-February proved to be the sweet spot.”

The latest collection event saw the Gnaala Karla Booja Rangers join the effort, working on Noongar Country to gather 103 additional fruits – containing approximately 1,000 seeds.

The rangers also assisted with drone operations, helping to map the estuary’s seagrass beds. Their involvement is an important step in integrating cultural knowledge with modern restoration science, strengthening connections to Country while improving the health of the estuary.

The restoration project has drawn support from a wide range of volunteers, including participants from the Seeds for Snapper initiative in Cockburn Sound, who made the journey south to lend a hand. Collecting seagrass fruit isn’t as glamorous as diving – this work involves wading through the estuary’s muddy shallows, searching for the tiny seed pods by hand. Despite the challenge, volunteers were eager to be part of the new initiative.

With seeds now being nurtured in aquariums, the next stage of the trial will see them planted at an upcoming estuary festival on April 6, where the public can take part in the restoration process.

This project is made possible thanks to Leschenault Catchment Council (Leschenault Estuary Connect Program), Lotterywest, Western Australia Department of Water and Environment Regulation, The University of Western Australia, Water Corporation and BCF – Boating, Camping, Fishing.