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Box Jellyfish

Phang Nga, Thailand
Level Contributor
331 posts
1 review
Box Jellyfish

Following comments on another thread, some good advice can be found from the PMBC here-

Box Jellyfish are highly venomous marine invertebrates. Their stings are excruciatingly painful, either initially or as an after-effect, and can be fatal for humans.

Although not all box jellyfish are dangerous to humans, stings from the most venomous varieties can cause death within four minutes if the venom reaches the heart and causes cardiac arrest.

Although the box jellyfish is not common in Thai waters, the Phuket Marine Biological Centre (PMBC) had recently reported the discovery of two families of box jellyfish – Chirosoides buitendijkl of the Chirodropidae family and those thought to be of the Carybdeidae family, in the waters off the coast of Phuket and Krabi in July and August 2008.

Following the discovery of the box jellyfish in Loh Sama bay, off Koh Phi Phi in Krabi province and in a trap in shallow waters, off Ao Nambor, on the east coast of Phuket island, PMBC has issued an official warning and circulated memorandums to all coastal provinces, urging authorities to set up signs warning of the presence of box jellyfish in affected areas. Dive operators have also been advised to be more vigilant before and during planned dives and to take additional precautionary measures to ensure the safety of their customers.

Visitors are advised to avoid swimming in the sea where box jellyfish have been spotted or are known to be present.

According to PBMC reports, up until recent months, there had never been any prior reports of this type of box jellyfish being found in Thai waters.

Although there have been no reports of box jellyfish stings in Phuket waters, the PMBC has issued a warning advising measures to take in the event of a jellyfish sting.


Visitors are advised to avoid swimming in the sea where box jellyfish have been spotted or are known to be present.

If swimming at a beach where there is a risk of encountering box jellies, take along a bottle of vinegar for the immediate treatment of stings. Following a sting, vinegar should be applied for a minimum of 30 seconds.

Steps to take if an individual is suspected to have a box jellyfish sting

Get the victim out of the water as soon as possible. Monitor their pulse rate.

The site of a sting should immediately be treated with vinegar to stop further injection of the toxin.

Do not rub or scratch the site of the sting or apply fresh water or alcohol to it.

Cardiopulmonary resuscitation (CPR) to be performed in the event of heart failure

Hotels and resorts situated along the Phuket coastline, and dive operators, have been advised to keep bottles of vinegar as part of their standard first aid kits as it is effective in treating stings from other kinds of less venomous jellyfish.

According to the PMBC, there have been no box jellyfish sightings on Phuket’s west coast beaches, where the seawater is generally too saline an environment for box jellies.

Web site:

The Phuket Marine Biological Center (PMBC)


Poulton Le Fylde...
Destination Expert
for Khao Lak, Khao Sok National Park
Level Contributor
45,458 posts
107 reviews
1. Re: Box Jellyfish

I only asked whether there are any at the moment in Khao Lak. As far I am aware none of the reports of these creatures unusually appearing in Thailand's waters were on or near the Khao Lak costline.

Whilst this advice is appropriate "in case" I wouldn't want to raise alarm unnecessarily by my comments unless sightings are actually confirmed, which it would appear is highly unlikely.

In fact after mature reflection as they say, I have had my previous reference removed.

Cape Panwa, Thailand
Level Contributor
3,063 posts
120 reviews
2. Re: Box Jellyfish


If there are jelly fish around i allways ask the question better to be safe and aware.At the moment Mr Jenson has told me the sea in Khao Lak Pakweep at the Le Meridien was full of them and they were as big as dinner plates. He went kayaking for a few hours and there was big batches of them in parts.I am glad i am not there at the moment as i have a horror of jellies.Hope they go in a few days.


Telford, United...
Level Contributor
167 posts
15 reviews
3. Re: Box Jellyfish

On 2 occasions during our recent visit to KL (KL Resort) we came across jellyfish. First time, whilst swimming, we came close to one large one. The 2nd time was whilst lunching overlooking the sea, we noticed a couple and then 3 or 4 and then a whole brood!! They seemed to all be coming in on the tide and then as they got closer they were being smashed on the rocks or just floating by. They were all dinner plate size or larger with very long/deep tendrills, all were a pale to deep orange colour. The hotel staff were all concerned to see them and advised people to stay away. The following day a couple could be seen out to sea but none after that. It is advisable to be aware and take care.

South Australia...
Destination Expert
for Phuket, Ko Lanta
Level Contributor
9,001 posts
455 reviews
4. Re: Box Jellyfish

I have had a little episode with a jelly fish just past Similana Resort, no idea what sort it was but was extremely painful and some nice long welts down my leg. Hurt for about 30 mins or so and took a couple of days for the welts to disappear. So just be careful! This was in low season.


Cape Panwa, Thailand
Level Contributor
3,063 posts
120 reviews
5. Re: Box Jellyfish


Last couple of days the jelly fish seem to have dissapeared only the odd ones now and the local fishermen have returned. Still be carefull though.


6. Re: Box Jellyfish

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Removed on: 14 October 2009, 01:05