There are estimated to be about four to 12 million crown of thorns starfish on the Great Barrier Reef. Photo: ARC Centre of Excellence Coral Reef Studies 
 
 An outbreak of coral-eating starfish on the Great Barrier Reef could become the worst on record, conservationists fear. 
 
 A report commissioned by WWF-Australia says the number of crown of thorns starfish could soar from between four and 12 million to 60 million by 2020. 
 
 "It would be like a locust plague devastating vegetation," Glen Holmes, co-author of The Starfish That Eat The Reef, said. 
 
 The devastating starfish are already believed to be responsible for the loss of around 60,000 hectares of live coral over the past 30 years. 
 
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 While there is nothing that can be done to halt the current outbreak, experts are appealing for tougher measures to prevent future plagues. 
 
 Harmful chemical fertilisers flowing off agricultural farming land and into the reef waters are fuelling the outbreaks by triggering algal blooms which feed the starfish. 
 
 "If we cut catchment pollution we can starve the baby crown of thorns starfish and prevent the next outbreak before it happens," Dr Holmes said. 
 
 "This will give the reef a chance to rebuild its coral cover and grow again." 
 
 Current state and national government investment has failed to achieve even modest targets and more money is needed to reduce pollution, he added. 
 
 If the outbreak follows the patterns of previous plagues then coral cover could be reduced to below 10 per cent, the report said. 
 
 AAP 
 
 Stay informed. Like the Brisbane Times Facebook page ||||| Magnificent star, a member of Paxillosida. Credit: Dr. Dwayne Meadows, NOAA/NMFS/OPR Since 2013, millions of sea stars native to the Pacific coast of North America from Baja California to southern Alaska have succumbed to a mysterious wasting disease in which their limbs pull away from their bodies and their organs exude through their skin; a disease researchers say could trigger an unprecedented ecological upheaval under the waves. 
 
 Now, a researcher in the College of Agriculture and Life Sciences has identified the deadly culprit as the Sea Star Associated Densovirus (SSaDV), a type of parvovirus commonly found in invertebrates. In a study published Nov. 17 in the Proceedings of the National Academy of Sciences, Hewson and colleagues present a genomic analysis of the newly discovered virus prevalent in symptomatic sea stars. 
 
 "There are 10 million viruses in a drop of seawater, so discovering the virus associated with a marine disease can be like looking for a needle in a haystack," says lead author Ian Hewson, a professor of microbiology. "Not only is this an important discovery of a virus involved in a mass mortality of marine invertebrates, but this is also the first virus described in a sea star." 
 
 Hewson suggests that the virus has been smoldering at a low level for many years. It was present in museum samples of sea stars collected in 1942, 1980, 1987 and 1991, and may have risen to epidemic levels in the last few years due to sea star overpopulation, environmental changes, or mutation of the virus. Sea water, plankton, sediments and water filters from public aquariums, sea urchins and brittle stars also harbored the virus. 
 
 The research lays the groundwork for understanding how the virus kills sea stars and what triggers outbreaks. The stakes are high, according to Drew Harvell, a professor of ecology and evolutionary biology and a co-author on the paper. As voracious predators on the ocean floor, sea stars are 'keystone' species which have a large role in maintaining diversity in their ecosystem. 
 
 Lead researcher Ian Hewson describes Densovirus. Credit: Cornell University "It's the experiment of the century for marine ecologists," said Harvell. "It is happening at such a large scale to the most important predators of the tidal and sub-tidal zones. Their disappearance is an experiment in ecological upheaval the likes of which we've never seen." 
 
 Both the National Science Foundation (NSF) and Cornell University's David R. Atkinson Center for a Sustainable Future provided rapid response funds to Hewson and his co-principal investigator Ben Miner, Western Washington University. 
 
 "The recent outbreak of sea star wasting disease on the U.S. West Coast has been a concern for coastal residents and marine ecologists," said David Garrison, program director in the NSF's Division of Ocean Sciences. "This study, supported as a rapid response award, has made a significant contribution to understanding the disease." 
 
 Explore further: Sea star wasting devastates Pacific Coast species 
 
 More information: Densovirus associated with sea-star wasting disease and mass mortality, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1416625111
– The number of coral-plundering crown of thorns starfish could boom from some 12 million to 60 million over the next four years, the Brisbane Times reports, and for Australia's Great Barrier Reef that would be akin to "a locust plague devastating vegetation," says Glen Holmes, co-author of The Starfish That Eat The Reef. This winter, though, an aquatic robot will be deployed to help slow the invasion of the invertebrates … by killing them, Scientific American reports. The COTSbot, developed at the Queensland University of Technology, is a small submarine outfitted with cameras, sonar, GPS, and a syringe-tipped arm. Following a pre-programmed path along the reef, the robot scans for crown of thorns starfish. Once it identifies its target, the COTSbot pumps it full of bile salts that, as Scientific American puts it, "digest the animal from the inside" before it can separate and regenerate (one starfish can produce millions of young). The COTSbot, which can kill more than 200 starfish in eight hours, will augment the efforts of human divers. “It's now so good it even ignores our 3D-printed decoys and targets only live starfish,” one researcher says. It is believed the starfish has destroyed some 230 square miles of live coral in the past three decades, per the Times, which says the outbreak may be linked to starfish-nourishing algal blooms resulting from fertilizer runoff. Overfishing of the starfish's predators may also be to blame, per Scientific American. Check out the COTSbot in action in this video.