Oyster Harbour and Princess Royal Harbour, two marine inlets on the south coast of Western Australia, lost up to 80% of the seagrass cover between the mid-1960s and 1988 due to clearing for agriculture and use of phosphatic fertilizers. A seagrass transplant pilot study in Oyster Harbour measured survival and growth in situ for 4 years. Long-term survival rates were high (96–98%), providing plants were anchored into the sediment. All unanchored plants were lost in the first winter. Following the success of the pilot study, a more comprehensive program began 3 years later with over 500 transplant units. The project demonstrates that Posidonia australis could be transplanted with a high degree of success into a protected embayment previously vegetated with seagrass meadows.

Seagrass

Method: Transplanting: rhizome fragments

Seagrass species: Posidonia australis

Planting density: 2.6ha transplanted

Hybrid structure: Rhizomes anchored into sediment