Port Phillip Bay shellfish reef project a first step in restoring Australia’s underwater kingdoms

Several nautical miles offshore, a particular diving boat is a mere speck in Port Phillip Bay. 

The bay, comprising nearly 2,000 sq. kilometres, followers southwards from Melbourne, Australia’s second-biggest metropolis.

Two divers carrying dwell shellfish are descending on a synthetic reef, taking one other small step in an formidable reef restoration project — the biggest but undertaken in Australia.

Known as Reef Builder, it’s backed by federal and state governments and overseen by The Nature Conservancy.

“Our Commonwealth funding has produced 40 hectares of shellfish reefs, and it is a actually implausible program,” Environment Minister Sussan Ley stated.

Artificial reef restoration

Shellfish reefs had been as soon as distinguished round a lot of the Australian shoreline.

Reef Builder is restoring marine habitats from Noosa in Queensland to Perth in Western Australia.

In 2017, Port Phillip grew to become the first of many deliberate future initiatives.

Two men in diving suits stand on a boat.
Simon Branigan prepares to dive with marine scientist Simon Reeves.(Landline: Tim Lee)

Mr Reeves has been closely concerned in the labour-intensive and difficult work.

Once a web site for a reef is recognized, a giant barge is used to convey in big limestone blocks which might be lifted by a crane and dropped overboard.

Within months they may grow to be, fairly actually, the constructing blocks of life.

Photo of a large barge is used to bring in huge limestone blocks.
A big barge is used to convey in limestone blocks.(Supplied: The Nature Conservancy)

Divers then disperse juvenile shellfish onto the brand new reef web site in a course of known as seeding.

The tiny oysters connected themselves to scallop or oyster shells which have been salvaged from seafood wholesalers and eating places, a part of a recycling initiative known as Shuck Don’t Chuck.

Breeding hatchlings

The younger oysters and mussels are grown on the Queenscliff Shellfish Hatchery, a state government-run facility on the western aspect of Port Phillip.

The restoration project has been producing the angasi or native oyster, typically known as the flat or mud oyster.

Port Phillip Bay was as soon as teeming with them, however in Melbourne’s early days they had been an all-too-convenient meals supply and the shellfish reefs had been a nuisance to marine navigation.

Photo of oyster shell.
The angasi or native oyster as soon as flourished in Port Phillip Bay.(Landline: Tim Lee)

Oyster shells additionally supplied the lime essential to constructing the town’s grand colonial buildings. Within a long time the shellfish reefs had been overfished or dredged to oblivion.

By the Nineteen Sixties, dredging for scallops in the bay additional decreased the inhabitants of angasi and blue mussels — it means the shellfish hatchery is essential to the restoration project.

“This is admittedly the linchpin of the restoration operation,” Mr Branigan stated.

Photo of a fresh oyster
The angasi oyster broods its younger internally and releases them into the water.(Landline: Tim Lee)

The scientists have needed to uncover a lot about the little-known and cryptic angasi oyster.

A man inspects oysters.
Kim Weston checks on the breeding standing of oysters used to replenish shares in the bay.(Landline: Tim Lee)

Unlike the extra widespread Sydney rock oyster, it broods its younger internally after which, when circumstances are appropriate, releases them into the water.

“We started off with little or no success; we possibly received 300,000 on the market in the preliminary phases,” hatchery supervisor Kim Weston stated.

An formidable objective

Twelve hectares of synthetic reefs have been constructed in Port Phillip — the final word intention is an formidable 100 hectares.

Even if that’s achieved, it can solely characterize a tenth of what was there on the time of European settlement.

Rebuilding these underwater kingdoms is paying dividends; six years into the project and leisure anglers are catching legal-sized whiting and different species that had been beforehand onerous to search out.

A man stands in a boat shed.
Bob Pearce is joyful to see marine life flourishing in Port Phillip Bay.(Landline: Tim Lee)

But Bob Pearce from the Albert Park Yachting and Angling Club, which has been instrumental in the reef rebuild, believed there was extra at stake than merely catching a feed of fish.

Oyster spat are grown in nutrient-rich tanks of seawater.
Newly spawned oyster spat are raised in these nutrient-rich tanks of sea water.(Landline: Tim Lee)

Marine scientists Simon Branigan and Simon Reeves are seeing a higher variety of marine life each time they go to the reef websites.

With an estimated 80 per cent of shellfish reefs misplaced worldwide — Mr Reeves believed the restoration of Port Phillip’s reefs had come in the nick of time.

Watch this story on ABC TV’s Landline at 12:30pm on Sunday, or on ABC iview.

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