Image: AMPTO

Tropical Water Quality Hub research on managing outbreaks of Crown of Thorns Starfish is already being cited by non-Hub researchers in a timely overview of the causes behind outbreaks of the coral-eating species on the Great Barrier Reef.

Crown of Thorns Starfish are a major focus for the Tropical Water Quality Hub with no less than three separate projects addressing ways of limiting their impact on the Great Barrier Reef.

The overview paper, published in the Marine Pollution Bulletin in March, examines Crown of Thorns outbreaks and concludes that “developing more effective and efficient physical control methods for Crown of Thorns ‘remains a key objective’ in limiting the impact of Crown of Thorns Starfish outbreaks on the Great Barrier Reef.”

It cites research by Tropical Water Quality Hub researcher Dr David Westcott from CSIRO, who said it offered important insight into the possible causes of Crown of Thorns outbreaks

“This paper tests the hypothesis that very high nutrient levels which result in increased larval survival and recruitment are the underpinning driver of CoTS outbreaks,” he said.

“The study indicates that CoTS larvae are actually able to thrive with much lower nutrient levels than has previously been assumed and that, indeed, the trigger for optimal growth is very much lower than previously thought. This suggests that the role of nutrients may not be as large as envisaged by the Nutrient Limitation Hypothesis and that we cannot ignore other hypothesised drivers of CoTS outbreaks such as the removal of predators of juveniles.

“Furthermore, it suggests that we cannot rely on water quality improvements to be the ultimate fix for CoTS outbreaks. Rather, manual control will likely remain important and we need to ensure that our approach to manual control is as good as it possibly can be. This goal is the focus of the TWQ Hub CoTS Research Program.”

Steve Moon OAM, Project Manager for the Association of Marine Park Tourism Operators, is responsible for the day-to-day field management of Crown of Thorns Starfish using divers.

Key to the entire program’s success is the cooperative relationship between NESP TWQ, AMPTO, GBRMPA and managing organisation the Reef and Rainforest Research Centre.

Mr Moon said science from the Tropical Water Quality Hub had been instrumental in improving control efforts, allowing them to cull over 80,000 Crown of Thorns from valuable reefs with a single vessel in the last six weeks alone.

“The Integrated Pest Management approach developed by the Tropical Water Quality Hub guides our control efforts and has contributed to an increase in our overall efficiency by enabling us to target populations at specific areas before they reach plague proportions,” he said.


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