Crown of Thorns Sea Star!

[World Wide Diver]

Yes they can release stress hormones while immobolised by rocks. However, we do the same thing sometimes as we cannot bear to see them eat corals on reefs which we regularly dive.

Best thing to do is to inject them with sodium bisulfate. Next best thing is removing them.

Cot guns and chemicals are expensive here for us and 1000x more so for locals. In addition, local people are unaware of implications from cot outbreaks and ignorant of methods of control. And, there are no funded programs like in Australia.

The Department for the Environment and Natural Resources (DENR) and the Bureau for Fisheries and Aquatic Resources (BFAR) do not fund any programs here in Mindanao (peanut cash) for this.

Shame is that it would not cost much to implement effective cot control programs here.

Until this happens, then local inititives like the one funded from John's own pocket are the best there are at the moment.

 

[CODMAN]

Hey WWD, just out of curiosity, do you know of any studies on the actuall incidence these kind of control measures have had on COT populations in the past? I'm just curious about the actual cost/effectiveness of this type of intervention.

Cheers!

 

[Babydamulag]

POKE THEM TO DEATH!! The fish love eating them....eggs schmeggs!! We are killing ours one dive at a time....DEATH TO COTS!

 

[jonix]

POKE THEM TO DEATH!! The fish love eating them....eggs schmeggs!! We are killing ours one dive at a time....DEATH TO COTS!

 

[Chuck SS]

The Crown of Thorns spawns once a year near midsummer. Likely what is being described as stress spawning above, is the stars ability to regrow another star from most any piece broken off. Several predators are known to exist such as the Triton Trumpet and the Harlequin Shrimp. Others include a species of Puffer, certain ones in the Wrasse family, some corals and likely more at different points in the Star's life cycle. Injection with a reef safe chemical or removal are the two approved methods of eliminating a Crown of Thorns (COT).

Earliest of the current wave of outbreaks came under notice of the scientific community during the late 50s with one report from the Ryukyus. Later in 68 and 69 the outbreak that nearly destroyed much of the reef from one end of the island to the other had begun. In this same time frame Guam was reporting an outbreak and shortly thereafter or nearly at the same time they were reported out of control on the Great Barrier Reef.

Sedimentation, lack of predation, both and more have been alluded to in the literature as throwing their normal balance out of whack. The Reef Rovers of Kadena Okinawa in association with the Univ of the Ryukus/Mr Yamamoto (I belief) formed a Starfish inquiry and control board in 1969 and the first of several eradication efforts were undertaken by outright removal of the Stars from the reefs.

From that point they came and went with each outbreak getting a bit more severe in numbers and range. Overall the impact was horrific as far as the reefs go to the point of eliminating long stretches of the reef from the island.

Much research has been done with much more to do and some of the lessons learned have been human intervention can make a huge difference but all too often it doesn't. Water temps and major current changes can drive the spread of the Stars. Sedimentation does seem to increase the Stars. Removal and injection control efforts deserve your attention and assistance if possible as well as assistance in counts and more.

In case you are wondering, I was one of the Reef Rovers and a leader during that mid-sixties campaign to understand and eradicate these natural but all too often out of control reef destroyers. Today with the reefs under fire from many quarters it will most certainly pay to err on the side of reef protection rather than going the other way.

Good Diving
Chuck S

 

[CODMAN]

Very interesting read Chuck! Thanks for taking the time to post it!

 

[World Wide Diver]

It's a real pleasure to hear from you. We had been told something about that cot outbreak in Guam.

I would be interested to know if you have any theories re the intelligence of cots as individuals or as a collective.

We have all noticed that seem to be able to communicate with each other very quickly. For example, we witness immediate colour change and defensive behaviour of cots in the immediate area around where cots are being removed; it's as if they know that they are in danger and react as a collective.

Maybe sounds a bit paranoid, but others have noticed this too.

 

[jigo]

i wonder if the stress CoTs get while being removed will also trigger spawning?

 

[CODMAN]

Very possibly pheromones... It's common in insects (ants for one). But I've never read anything about it in marine life. But then again, I've never searched for info on it in marine life either! Interesting stuff...

It's a real pleasure to hear from you. We had been told something about that cot outbreak in Guam.

I would be interested to know if you have any theories re the intelligence of cots as individuals or as a collective.

We have all noticed that seem to be able to communicate with each other very quickly. For example, we witness immediate colour change and defensive behaviour of cots in the immediate area around where cots are being removed; it's as if they know that they are in danger and react as a collective.

Maybe sounds a bit paranoid, but others have noticed this too.

 

[kosmonooit]

Thanks all, its very interesting topic, and one of real concern for us reef lovers.

However how does this threat rank against say acidification of the sea, which I understand is a major factor as well due to global warming. It also seems the population booms of cot's could be a by-product of human acitivity - according to wiki: "Increasing outbreaks are also thought to be caused by possible environmental pollution triggers. Algal blooms caused by agricultural run-off may supply predators of Crown-of-Starfish larvae with plentiful alternative food sources"

I first saw cot's in action this year making there way through some coral gardens in the mouth of Subic Bay earlier this year, there are really incredible creatures - almost like something out of science fiction, like a 11-dimensional psychedelic catapillar

Any idea as to what their communication medium used to communication stress and danger? chemical messengers? Sonar? electro-magnetics? Clairvoyance?

thanks again.