Crown of Thorns

[scubaskipper]

When I worked on the big island, it was my understanding that COT were not native to Hawaii and that TT and certain shrimp were the only known predators. It was very interesting to see how TT and COT reacted to each other and how fast a COT will run from a TT. It was also interesting that the number of TT was less every year due to collecting. You can also disturbed the hunting behavior of the TT if you moved it. It was also believed that a small slice in the central disc would possibly ease entry for the shrimp to be able to eat them from the inside out. Another theory was that too much damage many also trigger a possible release of eggs. You never ever wanted to cut it into parts. Because of the isolation of the islands, when non natives are introduced they can, in a very short time, do serious damage to the ecosystem. Too much fert. run off is thought to trigger a population explosion in COT. This is a very real possibility with the amount of agriculture on the island. As always, when in doubt, leave things the heck alone.

 

[MauiScubaSteve]

Depending on one's perspective, nothing is native to the Hawaiian Island's terrestrial ecosystem or the Hawaiian Island's reef ecosystem. The Islands formed by undersea volcanoes venting steaming lava until breaking the oceans surface and continuing up to at least 14,000 feet above sea level.

Every living thing on every Hawaiian Island / reef was introduced or migrated from somewhere else.

As far as current scientific terminology is concerned, if you arrived in the Hawaiian Islands before Captain Cook you are "native" but if you arrived after Cook you are "not native" (BC and AC).

"Endemic to Hawaii" is how we describe life forms that are "only found in the Hawaiian Islands." Prior to Cook's "discovery" (La Perouse actually discovered the Islands first) the local human population had sent voyaging canoes to distant lands, so Hawaiians are "native" but not "endemic."

It is pretty much guaranteed that both TT's and COT's were established on Hawaiian reefs long before even the first humans landed on Hawaii's shores, so TT's and COT's seem to be "native" but are clearly not "endemic."

There are many life forms in the Hawaiian Islands that were "introduced" or "migrated" AC; only a few of which we define as "invasive." The main three that come to my mind with regards to reef ecosystem are blue stripe snapper, peacock grouper (both introduced by Hawaii's Fish and Game) and snowflake coral (bilge introduced?).

I would love to see documentation of anybody who knows anything about COT's worrying about a destructive population boom in Hawaiian waters.

 

[Allison Finch]

Two examples of killing Crown of Thorns, Big Island, Hawaii, December 2010. Is the technique employed effective?
YouTube - SCUBA Hawaii: Kill Crown of Thorns?

The problem with slicing the COT is that, when damaged like this, they will spontaneously spawn throwing thousands of egg/sperm into the water. This will cause a population boom....immediately.

The Japanese used to slice up the lions mane jellyfish until they discovered that they, also, instantly spawn when sliced up. They created an even bigger problem.

To kill them, scoop them up and bake them in the sun. They may spawn, but the eggs will dry up and die.

DON'T CUT THEM UP!!

 

[Down2bizDiver]

I agree with Hale in that there is no educational merit in the video other than exactly what not to do.

DON'T cut the COT into lots of bits
DON'T try feeding the COT to helmet shells
DON'T flail around excitedly thinking you are doing the world a favor-you aren't
DON'T kill COT's in Hawaii-they have been a problem elsewhere, but NOT HERE. Leave our wildlife alone!

The diver with the knife in the first part of the video is native Hawaiian and ship's officer on the liveaboard. The second diver, who misidentified the helmet shell, is a dive shop owner not from Hawaii.

 

[MauiScubaSteve]

The diver with the knife in the first part of the video is native Hawaiian and ship's officer on the liveaboard. The second diver, who misidentified the helmet shell, is a dive shop owner not from Hawaii.

I am confused about your participation in this thread

Is the technique employed effective?

AISI, above is the pertinent typing in your first post. Below is a pertinent reply;

I agree with Hale in that there is no educational merit in the video other than exactly what not to do.

DON'T cut the COT into lots of bits
DON'T try feeding the COT to helmet shells
DON'T flail around excitedly thinking you are doing the world a favor-you aren't
DON'T kill COT's in Hawaii-they have been a problem elsewhere, but NOT HERE. Leave our wildlife alone!

IMHO, your second post has no pertinence.

 

[DevonDiver]

From Wikipedia:

Crown of Thorn Starfish -Natural predators

Venomous, sharp spines cover nearly the entire surface of the crown-of-thorns. These natural defenses make it a very unattractive target for most other reef predators. In spite of this, the Giant Triton (a mollusc) and the harlequin shrimp attack and feed on crown-of-thorns starfish. Some large reef fish, particularly humphead wrasse, may also prey on the starfish.[2]
Sea star larvae are planktonic, so the major population control of the species comes from planktonic predation of junior species members.
In an interesting reversal, a large solitary coral polyp of the genus Pseudocorynactis has been observed attacking, and then wholly ingesting a crown-of-thorns starfish of similar size.[3]
Decline in predator populations (through overharvesting, habitat destruction) has also been offered as an explanation for increasing outbreaks of crown-of-thorns starfish.

I've been involved in systematic 'culling' of CoTs in the Philippines. The programs were instigated due to population explosions and subsequent reef damage. The most effective technique is to collect the CoT and remove them from the water. They can be dried out, buried or burnt.

As with any starfish, cutting off a limb can lead to re-growth. Stabbing them is ineffective.

 

[Down2bizDiver]

I am confused about your participation in this thread
AISI, above is the pertinent typing in your first post. Below is a pertinent reply;
IMHO, your second post has no pertinence.

The thread is how to kill COT. The video I posted shows 2 examples of attempts to kill COT and I asked if the techniques shown are effective. Replies point out that the diver did not have a Triton Trumpet thus ineffective and that the stabbing shown is also ineffective and another reply from a poster identifying self as a Hawaiian says don't kill them, leave Hawaiian sea live alone. I was merely pointing out that the diver doing the stabbing is a Hawaiian, thus in conflict with the Hawaiian poster who says don't kill them.

My suggestion is for posters here re: ineffective technique / don't do it ought to also post comments on youtube where the video is located so that comments might reach a wider audience.

 

[MauiScubaSteve]

Your location is listed as Texas; have you ever met an ignorant Texan? I'm from Colorado and I've met plenty of ignorant Colorado people. Believe me, ignorant Hawaiian waterman exit too.

Shoot's, "Fisheries Management" was ignorant back in the late 50's, early 60's; many fish species were introduced to Hawaii's waters by the "Government Fisheries Department" and some are continually increasing their already significant negative impact to the native ecosystem.

Peacock hind (grouper) and bluespotted hind are only 2 of the 4 obvious introduced species we see on pretty much every dive. :shocked2:

Posting disclaimers on YT videos sounds like tilting windmills with horse and lance.

 

[Down2bizDiver]

Your location is listed as Texas; have you ever met an ignorant Texan? I'm from Colorado and I've met plenty of ignorant Colorado people. Believe me, ignorant Hawaiian waterman exit too.
Posting disclaimers on YT videos sounds like tilting windmills with horse and lance.

I have no idea what your point is. I apologize for posting on this thread, one that had been dead since 2003.

 

[smellzlikefish]

I did say "our wildlife" because I live in Hawaii but I was not speaking for Hawaiian residents, only those in the know.

If the thread is on how to kill COT, then the first rule is find somewhere that has a surplus of COT's. Native Hawaiian or not, the divers in that video were obviously misinformed. Someone told them that COT's are a problem on some reefs, so they took it upon themselves to try to be heroes, causing damage instead of helping.

Hale was simply pointing out that stupid people are everywhere (Hawaii, Texas, Colorado, and even my home state of Connecticut), so the diver's place of birth does not give him some kind of divine intelligence. There was some local guy (not sure if he was native or not) who shot a monk seal on Kauai, does his place of residence mean he's in the right? My opinion is they're both idiots, Hawaiian or not.