Crown of Thorns

[DeepSeaFox]

I have witnessed a number of different reactions to these little terrors from Divmasters/instructors and divers in varios parts of the world.

Does anyone have a view on what the "right" thing to do is.

 

[DiveTub]

This is how we do it.

1: Pick up crown of thorns with a spade like object, Do not touch the COT or damage it in anyway.
2: carry to boat or shore.
3: carry at least 100m away from the water, the COT is able to move a fair distance overland.
4: Turn upside down on a rock and let it sunbake for a week or so

This seems to be terminal for the COT.

 

[drbill]

Totally dependent on where you are. The crown of thorns in the "Sea of Cortez" is native and controlled through the ecosystem's normal functioning. It still eats coral, but this is something the system has evolved with.

On the Great Barrier Reef, as I remember it, they are not native (or is that there are human introduced substances that have caused an unnatural increase in population sizes? I have not dived there in a few years.). There the ecosystem has no natural defense against them since it did not evolve with them over time.

One must be careful to think of the context an organism is in before over-reacting. People in the Casino Point Dive Park kill sea urchins because they think they kill living kelp plants (or just to feed the sheephead and other fish). This is wrong, especially since they usually kill the black urchin (Centrostephanus) which is not implicated in urchin barrens and not the purple urchin (which can cause barrens elsewhere although not in the Park).

Due probably to the healthy lobster and sheephead populations in the Park (and probably the warmer water temperatures which make echinoderms more vulnerable to some diseases), sea urchins are controlled naturally and should not be killed. Not to mention it is a protected reserve.

Dr. Bill

 

[DeepSeaFox]

Sydney_Diver once bubbled...
This is how we do it.

1: Pick up crown of thorns with a spade like object, Do not touch the COT or damage it in anyway.
2: carry to boat or shore.
3: carry at least 100m away from the water, the COT is able to move a fair distance overland.
4: Turn upside down on a rock and let it sunbake for a week or so

This seems to be terminal for the COT.

If you are in a site where you see more than one it would not be practical to try to carry them back.

What specifically is the issue with damaging them ?

 

[DeepSeaFox]

drbill once bubbled...
Totally dependent on where you are. The crown of thorns in the "Sea of Cortez" is native and controlled through the ecosystem's normal functioning. It still eats coral, but this is something the system has evolved with.

On the Great Barrier Reef, as I remember it, they are not native (or is that there are human introduced substances that have caused an unnatural increase in population sizes? I

Thanks for the Info, Where else are they indiginious ?


As I understand it they caught a ride to the GBR somehow presumably on a ship, and are not natural.
I am also guessing they are not native elsewhere in Asia but they seem to be everywhere nowadays. At least I cant remember that I've been somewhere where I did NOT see at least one.

Judging by the typical reactions I had assumed they are considered a serious issue all over Asia.

 

[DiveTub]

DeepSeaFox once bubbled...


If you are in a site where you see more than one it would not be practical to try to carry them back.

What specifically is the issue with damaging them ?

COTS are like Starfish and Anemones, if you break part of them off that part will form into a new COT.

More than one means a big bag, as long as you are very careful not to have the bag and in doing so the spins touch you while you are swimming, I have been hit by a couple, last time on my finger, that one tiny prick caused my finger to increase in size by 4 times, it was agony to move it for a week, and it took 3 weeks for the swelling to go down. Boys don’t get any ideas it bloody hurts

 

[Gilligan]

I haven't seen what I consider great numbers of COT's here on Maui. My Hoover "Hawaii's Sea Creatures" book states they have not created extensive damage here.
I don't mess with them as I leave that to the balance of nature. Triton's Trumpet's and Harlequin Shrimp's prey upon the COT.
:shades:

 

[Snoopy]

Was told during Project Aware last year, that if the population is many, a quicker way is to inject it with a chemical - copper sulphate or something.

I didn't pay attention to this last part, coz we have the "license" by the resort to scoup up as many COT as we can.

And we are having fun doing it. It was like bomb squad trying to defuse a live-unit. Everyone looked and only a few dared to move forward to bag it.

It was lift in the bag on the cement floor. May be to be thrown into the BBQ pit after the fun was over.

Sydney_Diver once bubbled...

4: Turn upside down on a rock and let it sunbake for a week or so

This seems to be terminal for the COT.

 

[DeepSeaFox]

Sydney_Diver once bubbled...


COTS are like Starfish and Anemones, if you break part of them off that part will form into a new COT.

How much is required for the parts to survive ?

What happend if you just slice it open a bit ?

If cut open what can eat them ?

 

[Charlie99]

Gilligan once bubbled...
COT in Hawaii. . Triton's Trumpet's and Harlequin Shrimp's prey upon the COT. :shades:

There's a woman DM on one of the Lanai boats that leaves a trail of Crown of Thorns under rocks. It doesn't kill them --- just slows them down a bit.

One day, though, we had seen a Triton's Trumpet earlier in the dive. She brought a COT over and placed it next to the TT. We got to watch the Triton chase the COT and then inject it's poison into the COT.