Q: Recently, I saw a CNN report that stated that Australia’s Great Barrier Reef has lost half of its coral the past 25 years. Even though cyclones have done damage, scientists also are blaming starfish. They say that killing the starfish will bring the reef back. How can they kill all of the starfish?
— William McKee Jr., Flowery Branch
A: Crown-of-thorns starfish are one of the reasons why the Great Barrier Reef has lost about half of its coral since the mid-1980s. Storms have accounted for 48 percent of the decline, the starfish are responsible for 42 percent and coral bleaching contributed to 10 percent of the coral loss, according to a study from the Australian Institute of Marine Science. Scientists want to focus on stopping the starfish, they said. "We can't stop the storms, and ocean warming (the main cause of bleaching) is one of the critical impacts of the global climate change," John Gunn, the institute's CEO, said in a release. "However, we can act to reduce the impact of crown-of-thorns." Scientists said controlling chemical fertilizer runoff into the coastal waters will slow the starfish's reproduction because they feed on plankton in their larval stage, according to the study. Plankton populations surge "when fertilizer runoff floods the coastal ocean waters with nutrients," according to CNN.com, which leads to more crown-of-thorns starfish. The starfish also can be killed by divers cutting them up or by being injected with acid, CNN.com reported. Scientists recently have discovered a beef extract that kills the starfish, but it's being tested.
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