Southernmost outbreak of coral-eating starfish detected in Great Barrier Reef

A severe outbreak of coral-eating crown-of-thorns starfish is occurring in the Swain Reefs, the southernmost location in the Great Barrier Reef Marine Park found to have the starfish during the current outbreak.

Field officers detected the starfish on 37 reefs while undertaking in-water surveys in December in the Swain Reefs, which extend from 110 to 250 kilometres offshore from the Gladstone–Rockhampton area.

Great Barrier Reef Marine Park Authority Director of Education, Stewardship and Partnerships Fred Nucifora said efforts were being dedicated to getting a more complete picture of the outbreak to inform the control efforts underway in the Marine Park.

“We’re concerned to find an outbreak of the coral-eating crown-of-thorns starfish this far south in the Great Barrier Reef Marine Park,” Mr Nucifora said.

“Until now, the current crown-of-thorns starfish outbreak was largely limited to the northern and central part of the Reef, between Townsville and Cooktown.

“The Great Barrier Reef is under pressure and protecting coral cover is important for the health of the broader ecosystem, along with other actions to build the resilience of the Reef.”

Australian Institute of Marine Science Senior Research Scientist Dr Hugh Sweatman said this was not the first time a crown-of-thorns starfish outbreak had been recorded in the region.

“Our long-term monitoring has shown that Swain Reefs suffered from similar severe outbreaks of crown-of-thorns starfish from the late 1980s to 2005, and were also damaged by storms including severe tropical cyclone Hamish in 2009 but have recovered well,” Dr Sweatman said.

“The crown-of-thorns starfish outbreaks in the Swains tend to occur independently from the main outbreaks that start offshore Cairns and expand south down the Great Barrier Reef.

“Our research divers will continue to survey the area to assess the effects of these outbreaks as they develop and to see if rates of recovery are the same as in the past.

“Coral reefs are always changing; they lose coral because of storms, predation by crown-of-thorns starfish, coral diseases and, in recent times, bleaching. Given enough time between these losses, reefs can recover. How much coral we see depends on the balance of these rates of decline and recovery.”

The Australian Government funds a crown-of-thorns starfish management program, administered by the Marine Park Authority.

Mid last year, the Australian Government committed an additional $14.4 million for another control vessel and a tender is currently open seeking prospective contractors to deliver this activity.

“This new boat will enhance our crown-of-thorns control efforts, enabling trained divers to cull starfish in more locations and help protect coral cover,” Mr Nucifora said.

The funding also included $1.5 million over three years for additional Reef-wide surveillance, which is supporting the surveillance for crown-of-thorns starfish in the Swains.

Field officers undertook surveillance and some pre-emptive starfish culling in the Swain Reefs before Christmas and are continuing surveillance this month. Options to respond to the outbreak in the Swains will be assessed following survey reports later this month.

The Great Barrier Reef Marine Park Authority’s recently released Reef Blueprint highlights the importance of ramping up crown-of-thorns control — one of the most scalable and feasible actions for reducing coral mortality and preventing further declines.

Image Courtesy: Joint Field Management Program