By Maddie McAllister, ACUA Board Member
Off the coast of Townsville, Australia, a shadow rises from the seafloor— a huge iron hull, at rest, lying on its starboard side. Sitting in between the Australian mainland and the Great Barrier Reef (GBR), the wreck has become an oasis in a desert. It is cloaked in corals and sponges, swarming with fish that vanish in and out of the wreck like ghosts. This is SS Yongala. To divers, it’s a world-renowned site – an underwater oasis teeming with life. To archaeologists, it’s one of Australia’s most iconic shipwrecks. But what if it’s something else as well? Something more?
Shipwrecks like Yongala, sit at a strange intersection: part relic, part reef, part time capsule, part habitat. While they are legally protected as underwater cultural heritage sites and treasured for their biodiversity, the true nature of their identity—as hybrids of the human and non-human world—is still underexplored. Yongala reminds us that on the Great Barrier Reef (GBR), these wrecks aren’t just static heritage—they are living systems. And right now, we know far too little about how they work.
SS Yongala – More than just a wreck dive
SS Yongala was an Adelaide Steamship Company vessel – built in 1903. A regular sight along the east Australian coastline, Yongala navigated the GBR, carrying many people from city to regional town in the days when this was far quicker than any route on land. Tragically, Yongala disappeared during a cyclone in 1911 with all 122 people on board. What exactly happened remained a mystery until decades later when the wreck was discovered lying on its side in 30 meters of water. Since then, it has become one of the most visited dive sites in the world, and a magnet for marine biodiversity.
Ecologically, Yongala thrives—home to sea snakes, barracuda, wrasse, coral trout, Queensland grouper, turtles, rays, sharks, sea fans and whips and more. Culturally, it holds the stories of early 20th-century maritime travel, sudden tragedy, and the development of Australia’s underwater heritage protection laws. The towering structure of Yongala encapsulates a range of incredible artifacts from the early 20th century – artifacts excavated throughout the 1980s range from navigational and radio equipment, personal belongings, dining ware and parts of the ship itself. Significantly, Yongala is the final resting place of the 122 people onboard. A tragedy that still echoes in the corridors of buildings the ship was meant to reach. A large bronze plaque is featured within Townsville Hospital, acknowledging the two-nursing staff who were meant to arrive, yet never did. Yongala’s significance ensured it was listed as a protected site under the Underwater Cultural Heritage Act (2018). Today, you can dive the site via one of the permitted dive companies – yet no one can enter the hull for both recognition of those whose remains lie within and the structural integrity of the hull itself.
Ecologically, Yongala thrives—home to sea snakes, barracuda, wrasse, coral trout, Queensland grouper, turtles, rays, sharks, sea fans and whips and more. Culturally, it holds the stories of early 20th-century maritime travel, sudden tragedy, and the development of Australia’s underwater heritage protection laws. The towering structure of Yongala encapsulates a range of incredible artifacts from the early 20th century – artifacts excavated throughout the 1980s range from navigational and radio equipment, personal belongings, dining ware and parts of the ship itself.
Significantly, Yongala is the final resting place of the 122 people onboard. A tragedy that still echoes in the corridors of buildings the ship was meant to reach. A large bronze plaque is featured within Townsville Hospital, acknowledging the two-nursing staff who were meant to arrive, yet never did. Yongala’s significance ensured it was listed as a protected site under the Underwater Cultural Heritage Act (2018). Today, you can dive the site via one of the permitted dive companies – yet no one can enter the hull for both recognition of those whose remains lie within and the structural integrity of the hull itself.
But somewhere along the way, its archaeological and cultural values have been overshadowed by the site’s diving fame and ecological allure. Yongala is a case study in duality—yet we continue to frame it through singular lenses: either as a shipwreck or a reef, a cultural artifact or a habitat.
Black corals, fish and a unique oasis for marine life
SS Yongala stands as a remarkable example of a bio-diverse marine habitat, where the boundary between artificial structures and natural colonization fosters a unique ecological niche. Recent studies, notably by marine scientist Erika Gress (2023), have highlighted the shipwreck’s role in supporting an exceptionally diverse marine community. Gress’s research focuses on the structural habitat provided by antipatharian corals (black corals) colonizing the wreck, which in turn offers shelter and breeding grounds for a multitude of fish species and macro-invertebrates.
The abundance of black corals on Yongala is particularly noteworthy, as these corals are more prevalent on the wreck than on nearby natural reefs. This proliferation creates a complex habitat that supports a high biomass of fish, potentially among the highest per unit area globally. Moreover, intriguing interactions have been observed between herbivorous fish species, such as the streaked rabbitfish (Siganus javus), and black corals, indicating complex ecological relationships that are still being unraveled.
Yet here, even this important research removes the cultural undertow of the habitat the black corals call home and, it highlights the need for integrated research approaches that consider both the ecological and cultural significance of such sites – a hybrid ecology.
Image Left: Black coral (antipatharian) colony on Yongala (credit: Victor Huertas).
What is a Hybrid Ecology?
A hybrid ecology refers to an environment where human-made objects and natural lifeforms interact in complex, co-productive ways. In shipwreck contexts, it means the wreck is no longer “just” a cultural artifact—it’s also become a living system. Coral encrusts metal. Fish spawn in sheltered parts of the hull. The wreck and the reef shape each other over time.
This idea draws from fields like multispecies ethnography (that considers how humans and non-humans co-exist and shape each other’s worlds) and new materialism (that suggests that matter—like ship hulls, sediment, and rust—has agency and influence). Hybrid ecologies challenge the old idea that wrecks are static remains. Instead, they are evolving, responsive ecosystems.
The Gap in the Reef: What We Still Don’t Know
Despite Yongala’s visibility, surprisingly little is known about the combined interaction of its cultural heritage and its ecological function. This is not just a Yongala problem—it’s a gap that spans across the Great Barrier Reef (GBR).
Of the more than 1000 potential shipwrecks across the GBR, only a handful have been found and even less archaeologically investigated. And none have been studied through a biocultural lens—combining insights from heritage, marine biology, and community knowledge.
Image left: Coral and fish abundance on Yongala’s hull (Victor Huertas)
Consequently, some questions remain:
- How do shipwrecks influence reef biodiversity over time?
- Could they serve as micro-refugia in changing oceans?
- How are they valued by divers and scientists alike?
- Are we missing crucial signals by failing to integrate these perspectives?
In a time when we’re investing in coral restoration and reef resilience, it’s surprising how absent shipwrecks are from that conversation. These sites may not be coral bommies [bommie is an Australian term for an isolated coral outcrop or pinnacle], but they function like them in many ways—structurally, ecologically, symbolically.
Why This Matters Now
The Great Barrier Reef is in flux. Coral bleaching, rising sea temperatures, pollution, and ocean acidification are shifting the ecological baseline. At the same time, our cultural memory of the reef—its shipwrecks, its maritime history—is slipping beneath the waves.
Shipwrecks, like Yongala, matter because they anchor memory. But they also serve as unexpected allies in the climate crisis: relatively stable, long-standing structures that support marine life and record environmental change over time.
If we don’t start treating shipwrecks as hybrid cultural-ecological assets, we risk losing not just the history of the reef, but parts of its ecological future too.
Before the Reef Forgets
SS Yongala is not just the remains of a lost ship. It’s an active, living system—a reef, a relic, a record of both human tragedy and oceanic transformation. And yet, our frameworks for studying and managing it remain fragmented. It’s time to bridge that gap.
To do that, we need to embark on interdisciplinary research – combining archaeology, ecology and other related disciplines. We need to embrace ideas and approaches that frame these wrecks as heritage systems not isolated sites.
Categorised in: Deep Thoughts