Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Flood Related Dynamics of Hervey Bay Seagrass are linked to Dugong and Green Turtle Distribution and Mortality. (#51)

Michael Rasheed 1 , Christophe Cleguer 1 , Paul York 1 , Cath Bryant 1 , Dan Clifton 2 , Rene Burgess 2 , Taryn McPherson 3
  1. James Cook University, Cairns, QLD, Australia
  2. Great Barrier Reef & Marine Parks Region, Queensland Parks and Wildlife Service and Partnerships, Department of Environment & Science, Hervey Bay
  3. Great Barrier Reef & Marine Parks Region, Queensland Parks and Wildlife Service and Partnerships, Department of Environment & Science, Brisbane, Qld

The Hervey Bay and Great Sandy Strait marine environments are among the most biodiverse in Australia and contain one of the largest expanses of deep-water (> 15 m) seagrasses in Queensland. Extensive flooding of the Mary River over two consecutive events in early 2022 resulted in persistent flood plumes in Hervey Bay and the GSS and concerns for the state of seagrasses and associated populations of dugong and green turtles. In response a range of assessments were initiated by the Queensland and Australian Government including assessments of seagrass and dugong and turtle populations. In May 2022 seagrasses in the bay had reduced to less than one third of their historical extent and where present cover was typically less than 1%. This was associated with an increase in strandings of green sea turtles and dugongs. Follow up surveys in November 2022 revealed some spatial recovery of seagrasses but the only substantive areas of dense seagrass were in the deeper water in the middle of the bay. Aerial surveys for dugong and turtle were also conducted in November and here we examine the relationships between seagrass recovery and the dugong and turtle populations and the prognosis for their recovery.