New threat to coral reef

Sydney – A major outbreak of coral-eating crown of thorns starfish has been found munching Australia’s world heritage-listed Great Barrier Reef, scientists said yesterday, prompting the government to begin culling the spiky marine animals.

The predator starfish feeds on corals by spreading its stomach over them and using digestive enzymes to liquefy tissue. The outbreak hits as the reef is still reeling from two consecutive years of major coral bleaching.

“Each starfish eats about its body diameter a night, and so over time that mounts up very significantly,” Hugh Sweatman, a senior research scientist at the Australian Institute of Marine Science told Australian Broadcasting Corporation (ABC) radio.

“A lot of coral will be lost,” he said.

That would mean a blow for both the ecosystem and the lucrative tourism industry which it supports.

The crown of thorns were found in plague proportions last month in the Swains Reefs, at the southern edge of the Great Barrier Reef, by researchers from the reef’s marine park authority, a spokesperson for the authority said.

The remote reefs, about 200km offshore from Yeppoon, a holiday and fishing town 500km north of Queensland’s capital, Brisbane, are well south of the most-visited sections of the Great Barrier Reef, where most culling efforts are focused.

But the marine authority already killed some starfish at Swains Reefs in December and will mount another mission this month, a director at the authority, Fred Nucifora, said.

“The complexity with the Swains Reef location is ... they are logistically difficult to access and it is actually quite a hostile environment to work in.”

There have been four major crown of thorns outbreaks since the ’60s in the Great Barrier Reef but it recovered each time because there were always healthy populations of herbivorous fish. The outbreaks are usually triggered by extra nutrients in the water but the reason for the current outbreak was unclear.

The reef is still recovering from damage wrought by the worst-ever coral bleaching on record, which in 2016 killed two-thirds of a 700km stretch of reef.

Yesterday, a report in Science found that high ocean temperatures are harming tropical corals much more often than a generation ago. The Great Barrier Reef covers 348 000 km2 and is listed as a world heritage site since 1981. – Reuters