James Cook University
The role of dugong and turtle grazing in Torres Strait seagrass declines
Dramatic declines in seagrass meadows in the Torres Strait Islands Western Cluster were recorded in 2019 and 2020. These meadows are culturally important and represent significant foraging grounds for green turtles and dugongs. The Torres Strait Regional Authority (TSRA), Rangers and Traditional Owners have identified the widespread declines in seagrass meadows in the Torres Strait Western Cluster as a critical concern. Seagrass meadow condition around Mabuyag Island, Orman Reefs and the Dugong Sanctuary has decreased dramatically from very good condition to poor and very poor condition in the latest Torres Strait Seagrass report cards.
This project will identify the extent that grazing by green turtles and dugong is driving the recorded seagrass declines, to inform management measures and any interventions that may be required. Megaherbivore exclusion cages will be deployed in seagrass meadows and maintained by Rangers and the community. Differences in seagrass inside and outside of exclusion cages will be analysed to establish the role of dugong and green turtle grazing in structuring seagrass meadows in two locations where declines have been observed. These results will form the starting point to establish potential causes of decline in this area.
Mabuyag Island and Orman Reefs in the western Torres Strait