Starfish eating fish may save reef from thorny peril

Photo: kevscoot.

Photo: kevscoot.

Scientists may have a new weapon in their arsenal against a reef-eating starfish that wreaks havoc on coral.

Marine biologists from the Australian Institute of Marine Science have discovered nine new fish species that eat the crown-of-thorns starfish, which is a large coral-eating invertebrate that has venomous thorns.

Project leader and principal research scientist Dr Frederieke Kroon used a genetic marker to detect crown-of thorns starfish DNA in fish poo and gut contents. They found eighteen species in total that were feasting on the destructive starfish.

“Our findings might solve a mystery – why reef areas that are closed to commercial and recreational fishing tend to have fewer starfish than areas where fishing is allowed,” Dr Kroon said.

The crown-of-thorns starfish are currently decimating parts of the Great Barrier Reef for the third time in the past 40 years, according to AIMS.

Dr Kroon says her team have notified the government about their findings in the hope the discovery can be used to save the reef.

“Understanding the level of predation on crown-of-thorn starfish by coral reef fish, as done by our study, helps understand the value of additional management tools,” Dr Kroon said.

Fisheries management and zoning, in particular marine protected areas, can also contribute to controlling the starfish outbreaks.”

A 2012 study estimated that average hard coral cover halved on the Great Barrier Reef from 1985 to 2012, with 42 per cent of this decline attributed to coral predation by the crown-of-thorns.

Biosecurity Research Centre director and Murdoch University professor Chad Hewitt says that the new study could be revolutionary in reef maintenance.

“There is a very strong interest in building the resilience of the reef,” Dr Hewitt said.

“Currently, reef management is very much oriented around physical removal, but natural predators are the best mechanism to control the starfish.”

However, Dr Hewitt warned that this solution may not be so simple, with species forced to eat the starfish due to lack of alternative food sources.

“These results may not be indicative of preference, more so the abundance of the crown-of-thorns,” Dr Hewitt said.

“There is a very significant concern that some reefs may not recover without human intervention.”