Reefs created in Sydney dredging project

The dredging of Sydney Harbour is another step closer to completion.

The dredging of Sydney Harbour is another step closer to completion.

Eight artificial reefs were created around the harbour in the last few months. The reefs are designed to replace the natural habitat destroyed by the dredging.

Bruce Hatcher, chairman of Marine Ecosystem Research at Cape Breton University, said 750,000 tons of rock was put in the harbour.

"This is big rock. This is the kind of rock you see used to armour shorelines and line breakwaters and that kind of thing," he said.

"It has a mixture of smaller pieces amongst it. It's all higgily piggily on the bottom, just the way nature placed rock on the bottom when the glaciers retreated."

The reefs will be monitored for five years to see if lobster, crab and other marine life locate there.