Jan 5, 2018 - To eat the hard coral, the crown-of-thorns starfish has an extrudable ... Crown-of-thorns starfish devouring Swain Reef, part of the Great Barrier Reef off Australia's east coast. ... Deadly starfish are feasting on parts of the world's largest reef ... sea up into the shelf, which correlates with starfish larvae growth.
Jan 4, 2018 - Related Story: Crown-of-thorns starfish DNA reveals coral killer's weakness ... The Great Barrier Reef Marine Park Authority (GBRMPA) has ... "It may be caused by nutrient up-welling from deep ocean waters, but that's still yet ...
Jan 16, 2008 - Recent marine surveys by scientists in the Great Barrier Reef have found that an explosion in the population of the crown-of-thorns starfish has ...
A Voracious Starfish Is Destroying the Great Barrier Reef
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Crown-of-thorns starfish devouring Swain Reef, part of the Great Barrier Reef off Australia’s east coast.CreditCreditGreat Barrier Reef Marine Park Authority, via Reuters
BYRON BAY, Australia — The Great Barrier Reef is literally being eaten alive.
Deadly starfish are feasting on parts of the world’s largest reef system, which is already threatened by rising ocean temperatures, the Great Barrier Reef Marine Park Authority said on Friday.
Crown-of-thorns starfish, a native species whose numbers occasionally grow so out of control they endanger the reef, have been detected on 37 sections of the southerly Swain Reef, more than 60 miles offshore, according to the park authority.
“Whenever coral in any location in the Great Barrier Reef is threatened or stressed, it is of concern,” said Fred Nucifora, a spokesman for the authority.
The reef is one of the planet’s largest living structures — big enough to be seen from space — and is home to thousands of species, including sharks, turtles and whales. Australia relies on it for about 70,000 jobs and billions of dollars annually in tourism revenue.
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Normally, the starfish contribute to the reef’s diversity by eating faster-growing coral species, which allow for slower-growing species to thrive. But at outbreak levels, the starfish are able to eat coral — a polyp that builds the limestone reefs on which they communally live — faster than the coral can reproduce.
To eat the hard coral, the starfish has an extrudable stomach that wraps around the coral and ingests it. A starfish can eat its body diameter in coral every night.
Since the inception of a control program in 2012, the marine park authority has culled more than 600,000 starfish from the northern and central reef areas, Mr. Nucifora said.
The cause of the outbreak is unknown. One hypothesis is that currents are bringing nutrient-rich water from the deep sea up into the shelf, which correlates with starfish larvae growth.
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The new outbreak comes as scientists warn that coral bleaching — death caused by the stress of rising ocean temperatures — is straining the reef’s ecosystem. According to a studypublished Thursday in the journal Science, the frequency of coral bleaching has increased to the point that reefs no longer have sufficient recovery time between episodes.
Mr. Nucifora said that two control vessels with divers travel to the reef 250 days a year to cull the crown-of-thorns population.
“Active control of the starfish is the most feasible and scalable action that we can take at this point in time,” he said.
The divers inject the starfish with a solution of bile salts orwhite vinegar, which kill the starfish without hurting other marine life.
Last year, the Australian government committed 14.4 million Australian dollars, or $11.2 million, to finance a third control vessel for the marine park authority.
Since the control program began in 2012, Mr. Nucifora said, the government has committed 34.4 million Australian dollars to the problem through 2020.
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Coral reefs are constantly undergoing change, and they follow a cycle of death and renewal, said Hugh Sweatman, a scientist from the Australian Institute of Marine Sciences.
“The critical question,” Mr. Sweatman said, “is how long will they get to recover?”
Jan 16, 2008 - Recent marine surveys by scientists in the Great Barrier Reef have found that an explosion in the population of the crown-of-thorns starfish has ...
Recent marine surveys by scientists in the Great Barrier Reef have found that an explosion in the population of the crown-of-thorns starfish has decimated parts of the region’s reefs and are now threatening part of the so-called Coral Triangle – one of the world’s richest regions of coral reef biodiversity.
Located between Indonesia, Malaysia, the Philippines, Papua New Guinea, Palau and the Solomon Islands, the Coral Triangle is home to some of the most genetically unique marine species. Researchers found that the predatory starfish have almost destroyed some of the beautiful reefs found near Halmahera, Indonesia, with 20% of the reefs already reduced to only 5% coral cover. The crown-of-thorns starfish is a type of echinoderm with protective spines all over its body, which eject a neurotoxin. It can grow up to 40 cm in diameter, and is equipped with anywhere from 12 to 19 arms. Found in tropical coral reefs from the Red Sea to the Indian and Pacific Oceans, they devour coral reefs by climbing and extruding their stomach over them in order to excrete a digestive enzyme which transforms the reef into consumable, liquefied tissue.
Three similar ‘outbreaks’ have been recorded since the 1960s. Though the reason behind this current starfish outbreak is not entirely clear, it is believed that it could be linked to agricultural runoff, which increases algal blooms that nourish the starfish larvae. The removal of the starfish’s natural predators, water salinity, temperature and human impact on aquatic ecosystems are also contributing factors.
However, the promising presence of species such as the bumphead parrotfish and Napoleon wrasse indicate a still relatively-intact ecosystem. The surveyors are now suggesting that the best way to slow the starfish down is to ensure that human activity in the area is reduced.
"Once you've got an outbreak, there's almost nothing you can do to stop it. The only way to ensure you've got some reef left at the end of it is to protect lots of other areas," says Dr Andrew Baird, an Australian member of the survey team.
"At this point it's just the corals, so if we can minimize the impact from the crown of thorns, there's still a lot of hope." ::The Age
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