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Science informs ship anchoring

Our scientists worked with port authorities to improve anchoring options for ships and protect marine life.

 

The Great Southern Reef extends south from Brisbane around the southern half of the Australian continent, which includes the coast off Wollongong south of Sydney.

The reef off Wollongong supports a diverse range of temperate marine plants and animals including fish relevant to commercial and recreational fishers. It is also where ships drop anchor while they wait to enter Port Kembla.

The challenge

Anchors can be big – cargo or freight ships use anchors that weigh several tonnes, plus hundreds of metres of steel chain that secure them to the ship. Anchors and chains can drag on the sea floor and damage the seabed environment, including plants and animals.

Operators of cargo ships waiting to enter Port Kembla had assumed the seabed was sediment. But local fishers were aware there were reefs in deeper water offshore, and surveys by the Royal Australian Navy about 20 years ago confirmed these reefs existed.

However, there were many knowledge gaps. No one knew what the potential risk to biodiversity was from ships anchoring in the area.

This offshore area is a big area to map. It’s only in recent years that technology, including multibeam echosounders, underwater cameras and sophisticated vessel tracking, has made it possible to know what seabed habitats or ecosystems exist and to see where ships are anchoring.