From coral trout and snapper to wrasses, butterfly fish and damselfish – the inshore reef habitats of Great Barrier Reef islands are known for their complex and rich fish communities.

This month our scientists are conducting visual surveys of reef fishes and benthic habitats of eight inshore island groups in the Great Barrier Reef, building on a 20-year long-term monitoring program at four of the island groups and four new monitoring sites.

The island reefs surveyed are high-value and high-use for tourism and recreational fishing, with areas monitored in no-take marine reserves and zones open to fishing – making the data highly valuable in understanding how fish communities change over time and how they benefit from marine reserves.

Lead researcher Dr Maya Srinivasan said while some reefs were degraded due to past impacts such as cyclones and coral bleaching, many reefs were in great condition with a variety of live coral and fish species.

The inshore fringing reef monitoring seeks to uncover important insights into fish communities in a range of different habitats, including nursery habitats such as mangroves and seagrasses, island fringing reefs, and deeper areas between reefs.

The program is part of the IMR Reef Fish Monitoring Project, funded by the partnership between the Australian Government’s Reef Trust with the Great Barrier Reef Foundation. This is a joint program managed by the Australian Institute of Marine Science, with support from TropWATER, University of the Sunshine Coast, Great Barrier Reef Marine Park and Queensland Agriculture.

TropWATER is working with OzFish and the Townsville City Council to use environmental DNA (eDNA) methods to improve waterway monitoring in the Australian tropics.

The project aims to understand what invasive and native species are in key waterways, to help monitor the health of our aquatic systems and improve management.

Lead researcher Dr Cecilia Villacorta-Rath said eDNA was an innovative and cost-effective technique to identify key species without the need of sighting them.

“eDNA analysis can capture the ‘DNA footprint’ that is left in the water – we don’t need to see the species to detect its presence,” she said.

“By collecting water samples and running an analysis in our lab, we can determine what fish species live in the creeks.”

“Long-term eDNA data will give an insight into the fish communities inhabiting these sampled creeks and how these fish communities change through time.”

Citizen science led programs like OzFish and Creekwatch have monitored the health of local creeks in Townsville using methods such as traps and nets in the past, which are labour-intensive and selective, and not able to capture the whole fish biodiversity present in a waterbody.

Dr Villacorta-Rath said eDNA was a valuable tool for these community programs to gain a more comprehensive understanding of the fish species found in these waterways.

“We have run multiple workshops in Townsville, to train community groups on how to take water samples for eDNA analysis.”

“Anyone can take water samples for analysis and it’s great to see so many members of the public get involved.”

More fieldtrips are planned for the Townsville, Herbert, and Burdekin regions. To participate in the next OzFish eDNA sampling event (being held in the Burdekin), please visit:  https://ozfish.org.au/event/edna-sample-collection-ws-burdekin-qld-march-2023/

This project is funded by the partnership between the Australian Government’s Reef Trust and the Great Barrier Reef Foundation and is being delivered in partnership with OzFish Unlimited, James Cook University (TropWATER) and Townsville City Council.