How Coffin Bay’s First Dive Shop is Helping Restore Lost Underwater Ecosystems 

Explorer Callum joins Coffin Bay’s first (and only) scuba diving company to learn about how they’re looking after an isolated underwater ecosystem.

The nudibranch had been resting on a sprig, barely the length of my pinky fingernail. The small, slug-like creature resembled something found in a suburban garden. But even amongst the disturbed sediment and layers of neoprene, I can sense Manny’s excitement.

It was a typical muck dive: low visibility on a loose sedimentary bottom, where keen eyes are needed to spot the weird and wonderful critters through all the silt. 

Manny had told me that this was the first sighting of the Polycera melanosticta species in the region. At the time, Manny had been cataloguing the different species found in the relatively unexplored waters of Coffin Bay on the Eyre Peninsula. This small nudibranch had been a big find.

It’s been nearly two years since my time in Coffin Bay and things have changed quite a bit for the town’s first and only scuba diving company. 

Coffin Bay Scuba Co. was established in 2021 by Manny and his wife Jessie. What started out as a desire to share the underwater worlds of the Eyre Peninsula with locals and tourists, has transitioned into a mission focused on restoring the loss of ecosystems in this rural and isolated part of the country.  

Read more: 8 Ways to Minimise Your Impact While Snorkelling and Diving

World-Renowned Oyster Farms

Coffin Bay has always been synonymous with seafood.

Guidebooks will show pictures of visitors in waders and rubber boots, standing in waist-deep water surrounded by rows of oyster racks. Shucking your own oyster is done there and then, in the soft-blue ocean, offering a simple and raw ‘ocean-to-plate’ experience.

For the locals of Coffin Bay, fishing and oyster farming have dominated as a pastime, a world-renowned export, and a means of putting food on the table.

This connection to the ocean predates colonialism, with the Traditional Owners and Custodians of the land – the Nauo people – using intertidal traps to contain fish, or ‘kuju’, in the shallow enclosure. The Nauo people also relied on the oyster reefs, an important source of nutrition and trading resources in the coastal communities.

Colonialism had introduced dredging, whaling, and the commercial exploitation of oysters in the region – the impact of which is evident in the state of the ocean floor to this day.

The oceans of Coffin Bay have long been seen as a source of wealth and sustenance.

An Afternoon Dive in Coffin Bay

Coffin Bay comprises a handful of different bays and estuary ecosystems, and each one is home to different species. There are also plenty of open ocean dive sites in the national park that offer bommies and ledges, which are home to larger, oceanic species.

Spotting the smaller creatures can be a challenge. But Manny’s eyes are trained to see through the slush and expose the little wonders of this unassuming ecosystem. He looks for any abnormal movement, flickering fins and eyes in the sand, staring back up at him.

Read more: A Beginner’s Guide to Scuba Diving

In the bay, sponge crabs scuttled beneath us; spotted pipefish sat still among the reeds; flatheads and weedfish watched us with great suspicion from the seabed. A Southern Pygmy leatherjacket stared back at us from the safety of its seagrass cocoon.

Only the head of a Southern-Keeled octopus was visible above the sand. Manny joined his arms across his chest and rocked them back and forth, signalling that the octopus is a mother, protecting her eggs. It quickly became clear that there was still plenty of life among the muck.

But fast forward two years and Manny says the dive I went on with Coffin Bay Scuba Co wouldn’t really happen like that today. There’s now less of a focus on tourism in isolation, aware of the damage it can have both above and below the waves if not put in check.

Manny still guides people on memorable dives, showing the unique life forms. But a dive will rarely be done without some form of survey or task designed to contribute towards conserving the underwater ecosystems.

A portion of the dive might be spent creating 3D models of the seafloor using photogrammetry techniques, conducting fish and invertebrate count surveys, or even just doing a simple clean-up dive.

‘I truly believe that tourists want to be a part of improving the places they travel to, as it leads to more meaningful and memorable experiences’, says Manny.

Restoring Coffin Bay’s Native Oyster Reefs

My dive in Coffin Bay had mainly been spent along a sandy bottom, with scattered rocks and sea grass.

But Manny knows this isn’t what the ocean floor should look like.

The seafloor had once consisted of sandstone and limestone bottom, with oysters growing over each other, providing reef and nursing habitat for fish to spawn and thrive.

Dredging practices and overfishing in the 1800s have resulted in the destruction of these native oyster beds. Without the natural filtration system that the oyster reefs once provided, around 1-2 metres of sand has filled in the bays and suffocated the ecosystem.

Water quality continued to decline from an increase in coastal developments and the inflow of nutrients and pesticides that flow from farmland. Without the natural filtration system provided by native oyster reefs, water and the quality of life in it continues to decline.

Luckily, leading oyster reef researchers are looking to rebuild Coffin Bay’s lost oyster reefs.

Coffin Bay Scuba Co has been essential in galvanising the community, with a strong desire from the locals to see these oyster reefs restored.

Diving the estuaries has been critical in data collection and monitoring stages but also in deploying semi-artificial reefs to the sea floor, such as biodegradable mesh bags filled with dead oyster shells from local oyster farms. Hydro-acoustics are then used to attract oyster spawn to settle on these semi-artificial reefs.

Scuba diving will continue to be an essential part of the process, ensuring that intrusive turfing algae won’t interfere with restoration and using underwater photography to reconstruct 3D models of the reef to observe changes.

Changing Perceptions Beneath the Waves

Coffin Bay Scuba Co’s priority has become less about tourism in recent years. The primary focus is now implementing a citizen science program around the Eyre Peninsula to develop baseline knowledge of the local marine ecosystems. This is done to ensure better protection going forward.

The company continues to train and guide new divers in these unexplored waters, showing them the variety of marine life that exists in their backyard.

The dive shop runs a scholarship program for local public school students. While the intention is to educate and inspire, there’s an added bonus of recruiting divers to carry out native oyster reef restoration work.

These students have already helped in collecting dead oyster shell deposits found around the bay, which have been placed in baskets and deployed in the water, inside and outside of sanctuary zones. These baskets are pulled out and analysed, with each shell checked under a microscope by students to count and measure oyster recruitment levels.

This data will indicate where the best place to begin restoration work is. Come summer 2024-2025, students will deploy the semi-artificial reefs, which will be settled upon by native oysters during seasonal spawning times.

Given the opportunity to venture underwater for the first time and contribute to restoration projects, local kids have been inspired to pursue careers in marine biology and environmental management. Coffin Bay Scuba Co. has become a staple in the community, continuing to nurture that love affair with life beneath the waves.

‘Providing educational resources for both diving and the local marine environment has greatly improved the community’s overall knowledge and understanding of how to better interact with our waters’, says Manny.

Joining Manny as he was beginning to chart life in these waters and log a new species in the area had made for great diving. It’s that sense of discovery and exploration — to see something new and witness the natural world in such close proximity — that keeps so many divers coming back for more.

But it also exposes the fragility of these worlds and the continued degradation of these ecosystems. Learning about what’s beneath the waves was just the start for Coffin Bay Scuba Co, triggering a mission to protect and preserve. And the team has set out to take other people on that same journey: from exploration to restoration, instilling a desire to take action.

Interested in helping out? Find out more at the Coffin Bay Oyster Reef website, where you can make a donation or learn more from the Reviving Coffin Bay’s Lost Oyster Reef podcast.