Assessing the ecological values of the reefs of the southern Gulf of Carpentaria

The marine park contains a National Park Zone, where extractive activities are prohibited, and two Special Purpose (Trawl) Zones where recreational fishing and authorised commercial fishing and trawling are permitted. Its management plan is due for review in 2028, creating a need for better information about the environmental values and condition of habitats within the park.

This project compiled, synthesised and analysed the limited available western scientific information on coral reefs in the southern Gulf of Carpentaria, both within and adjacent to the marine park. It aimed to support future management and research and return information collected through previous scientific studies to Traditional Owners.

Approach and findings

The research team reviewed available scientific literature and datasets, including historical bathymetric mapping and ecological surveys of coral reefs and fish communities. The team also analysed Reef Life Survey data and compared southern Gulf reefs with reefs elsewhere in the Gulf, the Great Barrier Reef and Western Australia.

Seven submerged reefs had been mapped by Geoscience Australia in the southern Gulf, including four within the marine park. These include large submerged shoals and patch reefs, as well as steep-sided pinnacles.

Available ecological surveys showed coral cover ranging from 10% to 40%, comparable with inshore fringing reefs of the Great Barrier Reef. Offshore reefs supported higher densities, biomass and species richness of reef fish than nearshore reefs, but there were no differences between reefs within and outside of the GOCMP. Fish communities were distinct from those at similar latitudes on the Great Barrier Reef and in Western Australia, combining widespread Indo-Pacific species with species characteristic of northern and north-western Australia.

The study also highlighted major knowledge gaps. Large areas of deep reef remain unstudied, ecological surveys have not been conducted in the past decade, and there have been no comprehensive assessments of reefs within the marine park’s National Park Zone. The current condition and resilience of these reefs to disturbances such as marine heatwaves and flooding therefore remain largely unknown.

Outcomes

The project provides the first comprehensive synthesis of western scientific knowledge about coral reefs in the southern Gulf of Carpentaria and a stronger evidence base for future marine park planning and management, such as helping to inform the 2028 review of the GOCMP Management Plan.

The project recommends further research on deep offshore reefs and shallow fringing reefs around the Wellesley Islands, together with a structured, long-term monitoring program. Remotely operated vehicles could help survey deeper reefs, while Indigenous ranger-led monitoring could provide an effective approach for monitoring shallow reefs and reporting impacts such as coral bleaching, crown-of-thorns starfish outbreaks and flood plumes.

By bringing existing information together and making it more accessible, the project can support Traditional Owners, managers and other stakeholders to identify research priorities and make informed decisions about the future management of these distinctive reef ecosystems.

Project location