Gathering Indigenous knowledge to replenish oyster reefs and country

When the Oyster-beds Act of 1868 was introduced the damage was already beyond repair. The first European settlers of Australia found a coastline virtually encrusted with oyster beds. As it came into Sydney Harbour, the first fleet had to carefully pick its way past oyster beds covering up to 10 hectares.

In the following years, Australia’s Aboriginal peoples no doubt looked on in horror as the oysters and the beds they rested on were savagely harvested, including to make lime for cement.

Some of those Indigenous witnesses would have been forebears of Dunghutti man, Mitchell Gibbs (PhD (Science) ’21). His family still lives in the part of Dunghutti traditional land now called Kempsey, in north-eastern New South Wales, though Gibbs himself moved to Sydney to study and pursue a career in marine biology. He has a special interest in oysters, but with a wider goal in mind.

“I want more recognition of the Indigenous practices that were used all around Australia for thousands of years,” says Gibbs who has a large, easy smile and a welcoming energy. “Indigenous people used techniques that promoted revitalisation. It was about propagating.

“They’d apply that to oysters, native grasses, yams. Lots of different things.”

The most visible evidence of the interaction of Indigenous peoples and oysters are the shell middens dotted around the coast and built up over thousands of years as oysters were eaten and their shells added to the stack by travelling groups passing through.

Middens in Sydney have been carbon dated to 6000 years old, though much older middens would likely have been destroyed by previous sea level changes.

“Middens are often markers of big oyster reefs now lost,” says Gibbs. “The reefs also fed and sheltered so much other marine life that there are efforts underway to bring them back. The part that’s missing is that Indigenous knowledge of oyster reefs.”

A lesson on following your interests

Perhaps unexpectedly, the road that brought Gibbs to marine biology went via forensic science, where he majored in chemistry and worked on chemical structuring. Gibbs was helped during his studies by scholarships that allowed him to continue his studies even when his father became seriously ill.

“If I hadn’t had a scholarship, I couldn’t have travelled to Kempsey to be there for my father during the times he needed me,” says Gibbs. “So, I probably would have had to quit doing my PhD.”

His forensic science studies completed, Gibbs was approached about a project, “The uni needed someone to look at the chemical structure of oysters,” says Gibbs. “It involved nuclear magnetic resonancing, which I’d done, and it sounded really interesting, so I took it on.”

The project led Gibbs to study marine biology which played to his passion for the environment, and he has since worked on papers with names like ‘The impact of climate change on larvae of oysters’ and ‘Can early exposure to stress enhance resilience to ocean warming in oysters?’

A vision for protecting Indigenous knowledge and practices

Now doing post-doctoral work at the University, Gibbs is preparing his proposal for gathering Indigenous knowledge of oyster growing.

“It’s knowledge that is mostly handed down through families,” says Gibbs. “There are places where families have been working with oysters and incorporating Indigenous understanding for generations.

“They are experts at what they do, and I want to be a conduit so they can share their knowledge more widely.”

It is thought that long before European settlement, Indigenous peoples may have used oyster aquaculture to encourage them to grow in more accessible bays and inlets. What is unquestionable, is that Indigenous people were fundamental to the growth of the oyster farming industry after natural supplies of oysters were exhausted.

The commercial growing of Sydney rock oysters started around 1870, with Indigenous people often finding the best locations and actually building the farms. Many Indigenous people are still employed in the oyster industry, which in 2019 was a $59 million industry growing more than 76 million oysters a year.

“There is so much Indigenous knowledge, not just about oysters, but so many other things,” says Gibbs. “If you asked me what my greatest ambition is, I’d say to properly incorporate Indigenous science into university science curriculums.”