Scientists: To save Great Barrier Reef, kill starfish
The Great Barrier Reef has lost half its coral since the 1980s, scientists say.
October 2nd, 2012
11:37 AM ET

Scientists: To save Great Barrier Reef, kill starfish

Australia's Great Barrier Reef has lost 50% of its coral since the mid-1980s, much of that because of a ravenous species of starfish that can each consume some 12 square yards (10 square meters) of coral in a year, scientists reported Tuesday.

According to a study by the Australian government's Institute of Marine Sciences and the University of Wollongong, the coral cover on the world's largest coral reef ecosystem suffered damage from tropical cyclones (48%), the crown-of-thorns starfish (42%), and coral bleaching (10%).

If current trends continue, the reef will lose another 50% of its coral in the next 10 years, the scientists said.

Stopping the starfish infestation is the one thing humans can do that can save the reef, they said.

"We can't stop the storms, and ocean warming (the primary cause of coral bleaching) is one of the critical impacts of the global climate change," John Gunn, chief executive officer of the institute, said in a press release. "However, we can act to reduce the impact of crown of thorns."

"The study shows that in the absence of crown of thorns, coral cover would increase at 0.89% per year, so even with losses due to cyclones and bleaching there should be slow recovery," Gunn said in the release.

Reacting to the study, the World Wildlife Fund said Australia must reduce fertilizer runoff as a first step to controlling the crown-of-thorns starfish.

“The debate is over. This latest research demonstrates that more decisive action to cut chemical fertilizer is urgently needed to prevent unprecedented and on-going outbreaks of Crown of Thorns starfish, which are in turn converting the Great Barrier Reef into rubble,” WWF-Australia spokesperson Nick Heath said in a statement.

According to the study, the starfish in its larval stage feeds on plankton, populations of which surge when fertilizer runoff floods the coastal ocean waters with nutrients. So plentiful plankton can lead to swarms of hungry starfish.

The starfish consume the corals by climbing onto them, thrusting out their stomachs, and bathing the coral in digestive enzymes, which liquefy it for ingestion. Adult crown-of-thorns starfish, ranging in size from 9 to 18 inches in diameter and with up to 21 arms, can eat nearly a square foot of coral each in a day.

The WWF's Heath said both the Australian government and the state government of Queensland, where much of the reef lies, need to take action now.

“What this report shows is that we need urgent recommitment from both the Commonwealth and Queensland governments that will significantly reduce chemical fertilizer pollution on the Reef,” Heath said in a statement.

“With the right political will we can stop the march of crown-of-thorns starfish in its tracks and save the reef," Heath said.

The starfish threat to the reef is nothing new, according to the institute's report. The starfish have lived on the reef for 8,000 years, and swarms of the coral predators have been recorded as far back as 1962. The last major outbreak of the creatures was seen in the late 1990s.

But pressure from the cyclones and bleaching resulting from climate change exacerbate the damage the starfish can do, the report said.

"The combined effect of these disturbances may result in such regular coral mortality and reduced growth that communities cannot fully recover," it said.

Previous efforts to curb starfish populations have been costly and ineffective, the report said. Those include cutting up the creatures (they tend to regrow their lost appendages) and injecting them with an acid (costs $300,000 a year and divers must inject up to 500 starfish a day).

The WWF said $3 million was spent to control a starfish swarm in 2003 alone.

Besides protecting the environment, WWF said loss of the reef means loss of jobs for Australians.

“Sixty thousand jobs in the tourism industry depend on us acting with urgency over the next few years,” the WWF's Heath said in a statement.

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Filed under: Animals • Australia • Coral • Fish
soundoff (105 Responses)
  1. JeffinIL

    Spongebob? What's an "Eviction Notice"?

    October 2, 2012 at 6:25 pm | Report abuse |
  2. Lee Goldman

    Crown of Thorns have evolved with the reefs for millions of years. We come along and disrupt the natural balance of the reef that, to our dismay, favors the population growth of the sea star and our solution: kill the sea star. Let's not address the problem and do things to restore the balance. Instead, let's play god and choose the reefs to survive over the sea star. I understand completely about how the reef is an ecosystem in which the sea star lives, so that killing the sea star would end up saving the sea star, but there is still something quite wrong in their equation. Simply put, their equation is lacking several variables and shows lack of foresight and responsibility.

    October 2, 2012 at 6:32 pm | Report abuse |
  3. Joe

    Why aren't they bringing up the starfish? Put them in a big crate and haul it up, use them for fertilizer or something.

    October 2, 2012 at 6:57 pm | Report abuse |
  4. fishdude

    Lee Goldman, you don't understand the issue. The runoff increases the likelihood that baby crowns will reach adulthood. That's what is causing the imbalance. The crowns don't need to die off completely – they are part of the ecosystem and do serve a purpose.

    October 2, 2012 at 7:28 pm | Report abuse |
  5. Alex

    They are going to kill Patrick,and Sponge Bob will be without a friend

    October 2, 2012 at 7:31 pm | Report abuse |
  6. John Blackadder

    Well, at least this time global warming isn't the culprit! That 10% is in the noise compared with the definable causes, and as usual, may not even be real.
    Now, if the starfish regularly hits the reef, should we be trying to fix a natural phenomenon at all. Maybe there is a reason the starfish surge and the coral dies back. maybe, like fire in the forests, its needed to reinvigorate the environment.

    October 2, 2012 at 7:36 pm | Report abuse |
    • therandom

      VERY TRUE. and that guy is crazy starfish are awsome. so are sharks if it wasnt for them coral reefs would be to over populated, the coral reef would die from the amount of fish. (true fact watched this on discovery channel and history channel) ,thats ONE of the reasons sharks are awsome!!!

      October 2, 2012 at 7:55 pm | Report abuse |
    • Foray

      Exasperating. The article clearly states that the explosion in Starfish is due to fertilizer runoff (humans) not something natural as nature intended.

      October 2, 2012 at 8:29 pm | Report abuse |
    • Adam

      Ahhhh isn't lack of understanding a grand thing? People like this are a dead-weight on society.

      October 2, 2012 at 8:56 pm | Report abuse |
    • jrh

      And maybe you're wrong and people who are a lot smarter than you and who study this stuff for a living know what they're talking about. And maybe, just maybe, we should try to wrap our tiny little brains around the fact that agri-business is killing the planet with the petrochemical fertilizers and pesticides and herbicides they're using.

      Just maybe...

      October 2, 2012 at 9:48 pm | Report abuse |
    • yankeefan

      Plankton flourish with agricultural runoff; microscopic plankton combine CO2 with calcium to form a shell, the oceans are the world's carbon sink. For those who believe in global warming, there's the answer. I have never seen a coral reef; If they get destroyed, so what; what good are they?

      October 3, 2012 at 6:31 am | Report abuse |
    • MDAT

      Global warming is real.

      October 3, 2012 at 1:54 pm | Report abuse |
  7. Bill McGowan

    These starfish are old news. Can't remember how many hours myself and dozens of volunteer divers spent collecting and removing them from the coral reefs on the Big Island in Hawaii in the mid and late 80's. Sorry to say it was a wasted effort. The coral reef's over there were devoured by these critters and have yet to show signs of a real recovery after all these years.

    October 2, 2012 at 7:36 pm | Report abuse |
  8. MashaSobaka

    Yes. Good. Let's treat the symptom of the problem rather than the root cause. That'll definitely help. NOT.

    October 2, 2012 at 7:40 pm | Report abuse |
  9. Ginger

    Kill off human beings and I guarantee coral reefs would flourish.

    October 2, 2012 at 7:44 pm | Report abuse |
  10. True

    Why not just control the population of the starfish that are there, or remove them & have them relocated somewhere else in the ocean or in water park or need to kill them!

    October 2, 2012 at 7:46 pm | Report abuse |
    • jrh

      Because their numbers have exploded due to the runoff from farms on land. There are WAY too many of them. And even if there weren't, do you really see relocating starfish as a solution? Seriously?

      October 2, 2012 at 9:49 pm | Report abuse |
  11. starfish

    i know that the reef is `a pretty big place that marine organisms live but you don't kill off an entire species of starfish to protect it. maybe we can find an alternative.

    October 2, 2012 at 7:50 pm | Report abuse |
    • Adam

      Who said anything about killing off the species? Read the article.

      October 2, 2012 at 8:57 pm | Report abuse |
  12. larry5

    Every time people that think they are smart try to fix nature they mess things up. I can' t wait to see this fix and what happens down the line.

    October 2, 2012 at 9:01 pm | Report abuse |
  13. robert

    Just tell the Chinese that these starfish will give them a big dong and make them tigers in the sack and they will be extinct by the end of the year.

    October 2, 2012 at 9:37 pm | Report abuse |
  14. seyedibar

    Last year they were saying that it was a strain of herpes that had destroyed half the GBR. That research was backed up by findings in the mediterranean and the caribbean, so I'd be hesitant to call this little starfish the main culprit.

    October 2, 2012 at 9:55 pm | Report abuse |
  15. Lysette

    Pretty simple, stop the polution and cancel all fishing remotely near the reef – best way to control starfish is big fish that eat them. You don't get big fish if you have commercial fishing anywhere near a reef. Sadly, neither intervention is ever likely to happen because agricultural industry and fishing industry advocates will never permit it.

    October 3, 2012 at 2:09 am | Report abuse |
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