People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.


Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution


Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

From 2005 to 2022, the main node of the ARC Centre of Excellence for Coral Reef Studies was headquartered at James Cook University in Townsville, Queensland (Australia)

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PhD Mid-Candidature – Ciemon Caballes


Friday 27th of March 2015; 11:00 to 12:00 hrs.

Building 19 (Kevin Stark Research Building) Room #106 (upstairs), JCU, Townsville
Ciemon Caballes
Ciemon Caballes

Outbreaking bad: Environmental influences on the early life history stages of the crown-of-thorns starfish

Abstract: Outbreaks of the crown-of-thorns starfish, Acanthaster planci, represent one of the most significant biological disturbances on coral reefs and remain one of the principal causes of widespread decline in live coral cover in Indo-Pacific reefs.  In the Great Barrier Reef (GBR) for example, predation by A. planci accounted for 42% of substantial declines in coral cover in the past 27 years.   Increasing frequency and intensity of outbreak episodes have resulted in progressively slower recovery, which consequently degrades the integrity of reef ecosystems.  Despite previous and ongoing efforts to control A. planci populations, outbreaks continue to occur throughout the Indo-Pacific and at many locations.  In some of these locations, the effects of severe outbreaks have been far greater than combined effects of all other major disturbances, including climate-induced coral bleaching.  Longterm or permanent solutions depend on filling crucial gaps in our knowledge of the biology of A. planci, particularly reproduction and early life history.  The main objective of my research is to explore variations in tolerances and vulnerabilities of the early life history stages of A. planci to variable environmental conditions.  This seminar will discuss the environmental constraints that could limit fertilization rates in A. planci and the interactive effects of high nutrient levels and low salinity on larval survival, growth, and development.

Bio: Ciemon completed his BSc in Biology at Silliman University in the Philippines.  He proceeded to work with the Coastal Conservation and Education Foundation after his undergraduate studies and was involved in several coral reef management projects throughout the Philippines.  He decided to pursue his MSc in Biology degree at the University of Guam in 2006, where he studied the role of chemical cues on the feeding ecology and distribution of crown-of-thorns starfish (COTS) populations around Guam.  After finishing his MSc, he continued to study and monitor chronic COTS outbreaks on Guam’s reefs and collaborated with JCU on developing novel techniques to control COTS populations. He is currently doing his PhD under the supervision of Prof. Morgan Pratchett, Dr. Jairo Rivera-Posada, and Dr. Alexander Kerr.  His research explores environmental influences on the reproductive, larval, and postsettlement biology of COTS.


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