“The loss of seagrass meadows within Cockburn Sound (south of Fremantle) was linked to the poor water quality evident during the 1970s,” said Mr Tunbridge.

“Over the last decade or more water quality has improved to a level reported to be theoretically suited to support seagrass growth, but the seagrass has not yet returned.”

Mr Tunbridge, his supervisors Dr Eric Paling and Dr Mike van Keulen, and a team of divers from Murdoch’s Marine and Freshwater Research Laboratory (MAFRL) successfully transplanted seagrass into the nine metre waters of Cockburn Sound during his Honours study, creating a platform for future seagrass rehabilitation efforts.

In an attempt to discover the best chances for transplantation success, Mr Tunbridge identified the best manual transplant method, and the influence of location within the Sound and depth upon the survival of transplanted Posidonia sinuosa.

Mr Tunbridge and the team from MAFRL hand-planted seagrass, using two different methods (plugs and sprigs), to 13 sites scattered over the Sound.

After six months he found that 82.7 per cent of plugs survived, more than double the survival of sprig transplants, and found areas which had conditions that seemed to be far more conducive to seagrass survival.

Having successfully discovered a seagrass transplantation method suitable for Cockburn Sound, Mr Tunbridge is helping the seagrass to grow during his PhD research.

“If seagrass was left to spread naturally it could take more than a decade to form a meadow,” he said.

“The next step is to look at growth regulators to speed up the process.”

Over the next three years Mr Tunbridge will be planting along the eastern bank of Cockburn Sound, Buchanan and Luscombe Bays at Garden Island, and various shallow water sites (three metre depth) within the area. The research will also assess the amount of stress imposed on the plants during transplantation, and the rate of recovery of seagrass within donor regions.