Cutting-edge research into ecological principles provide foundation for starfish control program

A new adaptive approach to managing the coral-eating crown-of-thorns starfish has reduced their numbers on entire regions of the Great Barrier Reef sufficiently such that coral growth exceeds losses due to starfish predation.

It’s a huge milestone for scientists and on-water teams behind the expanded Crown-of-Thorns Starfish Control Program who have now proven their control methods successful at a regional scale, building on their previous ‘site-specific’ focus.

Researchers from a range of institutions have been instrumental in addressing the starfish problem through a co-ordinated control program and strategy funded by the Australian Government’s National Environmental Science Program (NESP) Tropical Water Quality Hub (NESP TWQ), started in November 2018.

A NESP technical report published on April 16 outlines the new ecologically-based framework for managing crown-of-thorns starfish. This includes NESP’s world-first adaptation of terrestrial Integrated Pest Management concepts and shows that the joint efforts undertaken are reaping rewards.

Using data from the first year of operations, researchers have evaluated the framework guiding the control program on the initial 140 high value reefs that have been managed on the Great Barrier Reef.

Drawing on the experience of the first year of operating the expanded control program, the report highlights how the refined decision-making process is guiding all aspects of control operations – from decisions made by individual divers, to the scheduling of voyages and operating the fleet.

Importantly, the information gathered by the control program and the latest research into crown-of-thorns starfish biology and reef ecology feeds back into the decision process, allowing for continual refinement and improvement of the strategy into the future.

Report co-author and project leader Dr. David Westcott said the results showed encouraging progress.

“Analysis of the data to date indicates that the Expanded Control Program’s decision rules are robust, and that the approach is effective in reducing starfish numbers to below the ecologically-sustainable levels which support coral growth and recovery across high value reefs,” he said.

“Critically, we have demonstrated that the approach effectively controls crown-of-thorns starfish at the scale of individual sites at a reef, at the scale of entire reefs, and across the suite of high value reefs throughout the Great Barrier Reef.”

Report co-author Dr. Cameron Fletcher at Australia’s national science agency CSIRO said, “What we have developed is a structured approach to decision making in the Control Program that assists managers, vessel operators and divers to make the best possible decisions in the light of data from the field, relevant ecological and logistical context, and the objectives of the program.”

Dr. Mary Bonin, another co-author of the report and Assistant Director at the Great Barrier Reef Marine Park Authority, said

“This is a great example of using science to achieve real-world outcomes for the health of the Great Barrier Reef. The decision support framework has been applied in the delivery of the control program since 2018 and since then we have been refining it based on the results coming in from the field.”

Sheriden Morris, managing director of the Reef and Rainforest Research Centre which manages the NESP TWQ, said co-operation was key to the program’s success.

“The new decision-making process is the product of researchers, control vessel operators and reef managers working effectively together to deliver a decision framework that provides a clear process for achieving management goals,” she said.

Crown-of-thorns starfish are a major cause of the loss of coral on the Great Barrier Reef, adding to the pressure placed on the reef by threats such as coral bleaching.

During an outbreak, crown-of-thorns starfish can eat 90 per cent of live coral tissue on a particular reef. The Great Barrier Reef is currently in the midst of its fourth major outbreak since the 1960s and management of this threat is key to its long-term resilience.

The technical report is available online, with more information on Implementation of the Crown-of-thorns research strategy: regional strategies and other crown-of-thorns starfish-related research available on the TWQ Hub website.


Photo: Cameron Fletcher 


Back to the July 2020 e-Newsletter contents