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

Highly resolved feeding estimations for crown-of-thorns starfish inform ecological projections and decision-making on the Great Barrier Reef (#166)

Josie F Chandler 1 , Will Figueira 2 , Peter C Doll 1 , Deborah Burn 1 , Ciemon Caballes 3 , Morgan Pratchett 1
  1. James Cook University, Townsville, QUEENSLAND, Australia
  2. School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
  3. University of Guam, Mangilao, Guam

Voracious feeding by elevated densities of Crown-of-Thorns Starfish (COTS; Acanthaster cf. solaris) continue to cause substantial coral loss on the Great Barrier Reef (GBR) with knock-on effects to both marine life and human livelihoods. Without a deep understanding of this feeding behaviour and its drivers, it is not possible to reliably predict COTS’ impact on coral communities or establish meaningful ecological thresholds, which hinders the most effective management of outbreaks. In this study we used technological advances to produce highly resolved estimates of daily feeding and compared the feeding behaviour from over 500 individuals across 5 regions of the GBR. This large-scale study showed that COTS were consuming an average of 130cm2 coral per day (± 6.91), however feeding rates were strongly driven by body size and season (~66% higher mean feeding rates during spawning months). There was found to be little variation in feeding rates with respect to regional differences in COTS densities or the availability of different coral prey. This data, coupled with our improved understanding of population dynamics through the course of an outbreak, will enable improved ecological projections of COTS impact on coral communities and ultimately inform prioritisation processes required for management decisions on the GBR.