Rehabilitation of Penrhyn Estuary continues

As part of the Port Botany container terminal expansion, Sydney Ports will spend $8 million to rehabilitate, expand and maintain Penrhyn Estuary, as well as create 6.5ha of seagrass habitat.

The aim is to reverse the declining quality of the estuarine habitat for migratory shorebirds, seagrass and saltmarsh and to retain the habitat as a site for migratory shorebirds.

Mapping seagrass beds off Foreshore Beach since 2003 identified a rapid natural decline of seagrass habitat in the area. In 2003, about 9.7ha of seagrass were recorded.

This had fallen to about 4.7ha in 2006. The seagrass continued to decline in 2007 and the most recent mapping in May 2008 identified only patches of mixed seagrass of poor quality equalling about 352m².

The cause of this decline is unknown but sediment on the seagrass beds is evident. The creation of 6.5ha of seagrass habitat as part of the Port Botany expansion will aim to reverse the seagrass decline.

Mapping also revealed that isolated patches of Posidonia australis would be lost due to construction works. To eliminate such loss, these patches have been transplanted to Quibray Bay, near Kurnell, in areas that already support existing Posidonia beds.

This transplant project was completed in September and a total of 100m² of Posidonia was transplanted. Initial results are positive. Sydney Ports will monitor the project during and after construction as part of the long-term monitoring of Penrhyn Estuary.