Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Turtle foraging behaviour in seagrass meadows of a sub-tropical port in the GBRWHA (#426)

Chris van de Wetering 1 , Michael Rasheed 1 , Alex Carter 1 , Mark Hamann 1 , Col Limpus 2 , Taka Shimada 2 , Emily Webster 3
  1. TropWATER, James Cook University, Cairns, QLD, Australia
  2. Department of Environment and Science, Queensland Government, Brisbane, QLD, Australia
  3. James Cook University, Townsville, QLD, Australia

Seagrasses are an important habitat within port environments and are monitored as an indication of port environment health. Recent research has shown that large herbivores, including green sea turtles, can significantly impact the condition of seagrass meadows within ports. However, this doesn’t appear to be consistent through time and space. Therefore, understanding the drivers of foraging decisions and strategy is required to better understand how green sea turtles influence seagrass conditions and vice versa. Advances in technology, specifically satellite networks and animal mounted telemetry tags, has allowed researchers to track the interactions between green sea turtles and their habitat. In my study, I analysed telemetry data from green sea turtles (n = 18) and looked for correlations with seagrass habitat datasets to spatially explore foraging behaviour. Preliminary results indicate a weak relationship between green sea turtles foraging efforts and seagrass biomass when a meadow is in a healthy state; however, as the meadow health deteriorates, the relationship strengthens, and green sea turtles increase their efforts in high biomass areas. Models from this study indicate that green sea turtles may also swap to an algal-based diet when the seagrass meadow is on the verge of habitat collapse. These results confirm that coupling an understanding of both seagrass condition and the herbivores that are feeding on them is important for monitoring programs linked to management.