Abstract: Population outbreaks of crown-of-thorns starfish (Acanthaster spp.) represent one of the most significant biological disturbances on tropical reefs, contributing to widespread and significant coral depletion throughout the Indo-Pacific. On the Great Barrier Reef, for example, outbreaks of Acanthaster spp., account for 42% of recorded coral loss over the last 27-years. Despite their importance, the demography and biology of Acanthaster spp. is poorly understood, especially in terms of understanding the potential cause(s) of population outbreaks. Effective management of outbreaks requires unequivocal understanding of the factors that both promote sudden population explosions, and normally regulate these populations at very low densities. The “predator removal hypothesis” was one of the first hypotheses to account for outbreaks of Acanthaster spp., attributing outbreaks to overfishing of key predators and predatory release. This hypothesis has gained recent support given increased frequency or severity of outbreaks in areas subject to fisheries exploitation. At present, specific field studies that aim to explicitly test the “predator removal hypothesis” are limited, and there remain many knowledge gaps, which may help to support, or refute, this hypothesis. In this seminar, I will outline the research to be undertaken during my PhD candidature to explore the role of predation in regulating Acanthaster spp. populations and contributing to highly dynamic fluctuations in their abundance.
Bio: Zara grew up in the UK and achieved her BSc (Hons) Biological Sciences at the University of Liverpool. She learnt to dive in Dahab, Egypt, returning a few years later to complete an internship with the Red Sea Environmental Centre, which confirmed her career path. Whilst diving in Thailand, Zara had her first encounter with a crown-of-thorns starfish (COTS) outbreak and was immediately interested in the causes of these outbreaks and their effects on coral reef communities. Supervised by Prof. Morgan Pratchett and Dr. Vanessa Messmer within the ARC Centre of Excellence for Coral Reef Studies, her PhD is looking at the role predation in population regulation of COTS.