Cockatoo Island / Wareamah Marine Restoration Pilot Project

The Cockatoo Island Marine Restoration Pilot Project, a collaborative initiative between the Sydney Institute of Marine Science (SIMS) and the Sydney Harbour Federation Trust (Harbour Trust), seeks to enhance marine biodiversity and expand our knowledge of the island’s marine environment.

This effort is integral to the Harbour Trust’s Cockatoo Island / Wareamah Draft Master Plan, aiming to explore and trial ecological remediation methods that could be applied more broadly at the site.

This pilot project not only tests the feasibility of restoration in areas impacted by historical disturbances but also sets the stage for creating educational and interpretive opportunities for visitors to discover the vibrant life of our iconic harbour. Additionally, it allows SIMS to evaluate the effectiveness of these restoration techniques, potentially linking this work to similar initiatives across the harbour to foster a healthier, more resilient marine ecosystem that benefits both nature and the community.

The History of Cockatoo Island / Wareamah

Cockatoo Island, known traditionally as Wareamah, is the largest island in Sydney Harbour, located at the confluence of the Parramatta and Lane Cove rivers. It connects to the waterways and homelands of the Wallumedegal, Wangal, Cammeraygal and Gadigal peoples. Historically, the island has undergone extensive transformations, with land reclamation and the construction of seawalls and pilings, effectively making it fully man-made in its current form.

In 1839, Cockatoo Island / Wareamah was repurposed as a convict penal station, marking the beginning of its colonial history. By the mid-19th century, it had evolved into a major shipbuilding yard, a shift that significantly altered its landscape and ushered in an era of industrial activity. This industrial legacy continued until the late 20th century when shipbuilding activities ceased.

Following its industrial era, Cockatoo Island began a transformation into a cultural hub. In 2010, Cockatoo Island Convict Sites was inscribed on the UNESCO World Heritage List with 10 other heritage sites nationwide, collectively known as the Australian Convict Sites World Heritage Property. Today, it serves as a vibrant part of Sydney’s cultural scene, a cherished location managed by the Harbour Trust, offering educational tours, a variety of community events, harbourside camping and attracting numerous visitors daily.

Despite its bustling surface activity, the waters around Cockatoo Island bear an underwater ecosystem that has been largely overlooked in historical and environmental assessments. Previous activities on the island have left an unclear impact on the surrounding marine environment. This initiative aims to shed light on the current ecological state and explore effective restoration methods. Through this project, we hope to integrate the island’s rich history with a renewed focus on marine conservation, providing a holistic approach to preserving and enhancing both the cultural and natural heritage of Cockatoo Island / Wareamah.

Cockatoo Island, February 1944.
John Jeremy Collection
Present day Cockatoo Island
Harbour Trust

The Cockatoo Island / Waremah Marine Restoration Pilot Project

This pilot project seeks to gain an understanding of the under-explored marine environment at Cockatoo Island / Wareamah in order to inform the marine restoration interventions to be implemented by SIMS. Initial assessments of the site began in April 2024 to explore what lies beneath the surface. An ecological baseline study was conducted using an underwater drone to identify benthic and fish communities, define habitats around the island, and assess water quality and pollution levels.

The results from the baseline study revealed a marine environment in better condition than anticipated, characterised by abundant kelp and a diverse range of fish species. Notably, the study documented the presence of the endangered White’s seahorse, marking the farthest known extension of this species into the Port Jackson estuary.

The White’s seahorse is endemic to southeastern Australia and can be found in Sydney Harbour, Port Stephens, Port Hacking, and other regions of NSW and QLD. Listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999, this species faces significant threats primarily due to habitat loss and degradation. Key natural habitats, such as the endangered seagrass Posidonia australis and cauliflower coral Dendronephthya australis, are also in decline, contributing to the seahorse’s precarious situation.

Moreover, the observation of the species at Cockatoo Island / Wareamah is significant not only for its geographical distribution, but it also demonstrates the potential for expanding SIMS’s Sydney Seahorse Project and enhancing conservation efforts within Sydney Harbour.

A White’s seahorse captured on camera at Cockatoo Island via underwater drone.
Pregnant captive-bred White’s seahorses in Chowder Bay
Jayne Jenkins

Future Plans

Following the ecological baseline study at Cockatoo Island / Wareamah, SIMS is now working on targeted marine restoration interventions tailored to the specific environmental conditions of the location. The project will prioritise restoration techniques and innovations such as eco-engineering to revitalise the underwater environment.

Once restoration interventions are underway, the project will include rigorous scientific monitoring to track the efficacy of these methods, aiming to improve future conservation efforts at Cockatoo Island and beyond.

Watch this space for more updates on what is coming to Cockatoo Island in late 2024!

SIMS vessel The Rampage arriving at Cockatoo Island.