Under siege: starfish meet their match

Coral cover at a popular recreational fishing and diving reef off Townsville is now better protected thanks to the efforts of a dedicated dive team and marine managers.

More than 22,000 coral-eating crown-of-thorns starfish were culled at John Brewer Reef by Pacific Marine Group, as part of the Great Barrier Reef Marine Park Authority’s starfish control program.

Great Barrier Reef Marine Park Authority Director of Reef Interventions Darren Cameron said this was an excellent example of on-ground action to protect coral cover on our iconic Reef.

“Starfish control efforts are taking place at high priority areas across the Great Barrier Reef — and this World Environment Day it is timely to celebrate this work,” he said.

“The initial surveillance of John Brewer Reef revealed the reef was experiencing a severe outbreak, with more than three starfish counted on every two-minute manta tow survey around the reef perimeter.

“After repeat culling visits over several months starfish numbers are down to ecologically-sustainable levels for coral growth. Repeat surveys indicate the reef no longer has an outbreak.

“This valuable reef spans 24.5 square kilometres and has a healthy 36 per cent hard coral cover that has now been protected from starfish outbreak.”

“Ongoing monitoring and culling visits will continue into the future to maintain the protection of coral on this valuable reef.”

The Great Barrier Reef Marine Park Authority’s Crown-of-thorns Starfish Control Program protects a network of high value coral reefs from outbreaks of coral-eating starfish.

Controlling crown-of-thorns starfish is a key initiative under the Authority’s Reef Blueprint, which outlines the top 10 actions to protect the Reef.

Additional funding of $24.8 million from the Australian Government enabled the Authority to expand the starfish control program to protect coral on additional ecologically and economically valuable reefs across the Marine Park.

The crown-of-thorns starfish, Acanthaster cf. solaris, is native to the Great Barrier Reef.

The starfish are a voracious predator of live coral, have a very high reproductive potential, grow rapidly to reach maturity, and can reach ‘outbreak’ densities causing significant damage to coral reefs.

There have been four major recorded outbreaks on the Great Barrier Reef since the 1960s, each lasting approximately 10 years. The most recent outbreak started in 2010.