*Featured Image: Mark Kriedemann.
Sydney Harbour is set to look a little different in the next five years thanks to the daring aspirations of a few marine biologists.
A team from the Sydney Institute of Marine Science (SIMS) is looking to reintroduce oyster beds into urban estuaries around Sydney, and they’ve set their sights on the city’s iconic harbour.
The oysters will make “the whole ecosystem kick back into action,” according to University of Sydney marine biologist Dr Ana Bugnot, who also doubles as a manager of the SIMS research program.
Dr Bugnot says the harbour used to be teeming with marine life before settlers harvested oysters. Then the area became “desolate”.
“We don’t know if we can bring them (life) back,” she said. But, by creating oyster reefs, life could return to the area naturally.
The idea for the research project was first floated in 2018 and received funding from the Australian Research Council, the Nature Conservancy, the Department of Primary Industries of NSW and the Sydney Institute of Marine Science Foundation.
However, there’s a catch.
The oyster restoration will mean placing large concrete blocks around the harbour, to allow oysters to settle on them and eventually grow.
If it’s approved, it’s a new look, and the reason the research project has met resistance.
The locations of the reefs have not yet been determined because of the difficulty in obtaining permits in Sydney, especially since the harbour has multiple uses and different parties can compete for space.
“For example, fishermen want it because they know more fish will come, but oyster reefs can be obstacles for boating…swimmers may also not like it because they could get cuts and so on.”
For that reason, researchers are focusing their efforts on first securing permits in less urbanised areas, although the aim is to secure Sydney Harbour and Botany Bay as the primary locations, according to a statement from the University of Sydney.
To create an oyster bed, spats (oyster larvae) must first be sold to the oyster growers, before being cultivated underwater in cages and trays at high intertidal levels for around a year. After that, they are collected and sold and can be placed anywhere.
“Oysters filter water, they help restore water quality and so aspects of the environment can be restored,” Dr Bugnot said. For instance, when seagrass is allowed to grow in optimum conditions with good water quality, it can then create more food for fish and invertebrates.
Dr Bugnot says oyster reef research has only just scratched the surface of possibilities. The next steps are to understand what oysters do and how they survive; and to test for other oyster species in the harbour.
“There’s definitely room for a few generations of scientists to study [this].”
— Story, Emily Harper. Additional editing Alex Turner-Cohen @AlexTurnerCohen