Monday, June 21, 2010

The Crown of Thorns' Revenge

Current Location: Anse Amyot, Toau Atoll, Tuamotus, French Polynesia 15-48.21S / 146-09.14W

As we have been diving the wall outside Anse Amyot, we have noticed one area of the reef that has the dreaded Crown of Thorns Starfish. These are about 18" in diameter with 12-16 arms, and bristly thorns 1-2 inches long. The Crown of Thorns eats coral polyps, and when their numbers increase, they can devastate a reef area pretty quickly.

The Crown of Thorns Starfish

In Australia, the Crown of Thorns has reached epidemic status and they are actively battling them. "Considerable effort has gone into developing methods to control crown-of-thorns starfish populations in local areas by the Great Barrier Reef Marine Park Authority (GBRMPA), CRC Reef researchers and the tourism industry. It is not possible to eliminate crown-of-thorns starfish from reefs where they are in outbreak densities but with sufficient effort, local areas can be protected."

"Some tourism operators in the Cairns region spend up to $300,000 each per year in crown-of-thorns starfish control. Some operations collect or inject 200 to 500 starfish each day in an effort to keep selected sites free of starfish. In 2001, the Queensland Government committed $1 million for reef management issues, including assisting the tourism industry in controlling populations of crown-of-thorns starfish."

Our friends on Visions who have gone ahead to western French Polynesia emailed us that Moorea has lost 95% of their reef due to crown of thorns. They urged us to think about trying to destroy any CofT animals that we encountered on Toau's pristine reef.

So on the last dive we made, when I saw a Crown of Thorns, I took my small dive knife which is permanently mounted on my BC and tried to poke a few holes in it. Ow! Those thorns, which look sort of rubbery, are really strong and really sharp!! I poked a few more of the ugly things with my small dive knife--and got poked back 3 more times for my efforts, before I wised up and decided to leave well enough alone. Moral of the story: Carry a bigger knife! Now my index finger hurts like hell, and is swollen and nasty looking.

We have looked up the Crown of Thorns in our Dangerous Marine Creatures book, which says "Even dead animals, washed up on the beach, are capable of causing severe pain to humans. The pain is well in excess of that due to penetration of a spine. Continuation of the pain, swelling, weakness, and limitation of movement may continue for many weeks or months, especially if any of the spine is left in the wound." In other words, there is some poison attached to the spines.

Oops. They suggest an X-ray or MRI to verify if any spines are embedded. We are a long way from a doctor or an X-ray machine, so we are taking the 'wait and see' approach. I has been 3 days now, and the one finger that got poked several time in the soft tissue by the knuckle is still swollen, and still hurts, though less than before. It also feels a little warmer than the adjacent finger. It seemed to me that there were no spines embedded--I just barely touched the spines. There is no visual evidence of anything left in the skin.

Though the wound seems clean, the slight fever in my finger has me a little worried. I am contemplating starting a course of broad-spectrum antibiotics. But I hate to take antibiotics 'just in case'.

Anyway, we will continue to try to exterminate any Crown of Thorns we encounter on the reef, but we'll be a lot more careful (gloves and a much longer knife).
At 6/17/2010 5:03 PM (utc) our position was 15°48.21'S 146°09.14'W

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