Crown-of-thorns: most immediate threat to reefs

Global warning on sea's silent killers
Leigh Dayton, The Australian 23 Jan 08;

"I don't want to downplay the threat of climate change to people and ecosystems, but it's not affecting the tropical reefs at present."

"The success of large marine parks, like the Great Barrier Reef Marine Park, is largely due to the primary role science plays in understanding what's going on."

FORGET climate change. The most immediate threat to tropical coral reefs is the ravenous crown of thorns starfish.

The claim comes from Andrew Baird, a marine ecologist with the Centre of Excellence for Coral Reef Studies and James Cook University in Townsville.

Along with Stuart Campbell, Indonesian program co-ordinator with the US-based Wildlife Conservation Society, Dr Baird has documented the health of reefs in the "coral triangle" of Indonesia, Malaysia, Papua New Guinea, The Philippines, Solomon Islands and East Timor.

"There seem to be outbreaks of the starfish throughout the coral triangle," he said, pointing to work conducted with WCS since 2005.

Dr Baird has also just returned from a survey trip along the coral reefs of Halmahera, Indonesia, where the team identified a massive outbreak of the starfish.

"It's killing a lot more coral than anything else, including climate change," he said. "I don't want to downplay the threat of climate change to people and ecosystems, but it's not affecting the tropical reefs at present."

According to Dr Baird, poor water quality is driving the outbreak because starfish larvae feed on the extra nutrients from fertilisers, soil and other contaminants.

Moreover, pollutants stick to corals and associated organisms, as well as having direct toxic effects.

The result: coral becomes unhealthy and also unattractive to other animals that settle on them.

"From what we've seen I'd say at least 20 per cent of the reefs have less than 5 per cent coral cover. You'd expect to see 40 to 50 per cent on a healthy reef," Dr Baird said.

In order to tackle the problems, coral triangle nations established a partnership last December. But DrBaird said details remained sketchy and did not mention the critical role of research in conservation activities.

"We are disappointed research is yet to be fully considered in the initiative," he said.

"The success of large marine parks, like the Great Barrier Reef Marine Park, is largely due to the primary role science plays in understanding what's going on."

Dr Baird pointed to efforts by the GBRMP Authority to work with farmers to reduce practices leading to run-off from fertilisers, pesticides and herbicides.

Scientists have also monitored the impact of the crown of thorns starfish on the Great Barrier Reef, the first step in reconstructing outbreaks, devising better control methods and boosting the resilience of corals to future assaults, whether from starfish or climate change.