Poster Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Assessing Cyclonic Impacts on Fringing Reefs: The Impact of STC Debbie on Blue Pearl Bay, Hayman Island, Whitsundays, North Queensland (#693)

Carlos CBG Botana Gomez 1 , Scott SB Bryan 1 , Luke LDN Nothdurft 1
  1. School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, Queensland, Australia

In 2017, Severe Tropical Cyclone Debbie (Cat. 4) tracked directly over the Whitsundays region causing a 40-95% reduction in hard coral cover.  Blue Pearl Bay (BPB) on the sheltered west coast of Hayman Island was home to a high-value fringing reef, but as STC Debbie made landfall, BPB became exposed to cyclone-generated swells that removed virtually all branching coral leaving a bare reef substrate as well as tilting several large >2 m diameter Porites spp bommies along the reef slope. Hard coral cover recovery has been slow. This study aimed to evaluate cyclone impacts on fringing reefs and to constrain where rubble is stored in fringing reef environments. We have mapped parts of BPB to identify locations of coral rubble and assess hard coral recovery 6 years after STC Debbie. Using two autonomous vehicles, bathymetry, and photogrammetry maps have been created to analyse the benthic cover. A significant rubble patch (>6000 m2) was deposited and has remained in shallow water <2 m in the southern bay and experienced little remobilisation. The information generated from this study is critical for assessing the impact of tropical cyclones on fringing reef ecosystems in the GBR and informing future restoration efforts.