Habitat - Where Are They?
There has never been any serious research in Thailand to gather data on deadly Box Jellyfish though the few times that fatalities have been attributed to a Box Jellyfish sting, some form of investigation has occurred though usually it doesn't last and isn't followed through.
Thankfully this is finally changing due mainly to pressure on tourism and potential damage to the industry when another official fatality occurs. It is believed that there is anywhere between 1 - 10 deaths in Thailand per year due to Box Jellyfish predominantly in indigenous communities.
Determining cause of death in Thailand can be a hit and miss affair and drownings particularly could be caused by stings though this in all likelihood would not be reported - a sting on Chaweng Beach in May 2009 had typical linear lesions but the doctor put it down to 'allergic dermatitis' while I know of one fatality where the police forced a death certificate on the bereaved partner of the victim claiming drunk drowning, in Thai!
Government medical officials are investigating the societal impact while marine scientists are learning all about the animals - processes are being put in place to better manage the problem but this is just the beginning and there is a long way to go.
So, where are they? Sampling of strategic areas is being undertaken to find this out. At the moment there is the Australian experience with the deadly Australian box jellyfish Chironex Fleckeri but it appears as though the situation is somewhat different in Thailand with the Australian Chironex's cousin looking slightly different and living in a different land/seascape and conditions. It's also different in the Philippines, Malaysia, Indonesia, Vietnam, Cambodia, East Timor and New Guinea.
The profile photo is of Thailand's Chironex-type Box Jellyfish swimming 50 metres offshore in clear water on a damaged coral reef at Koh Samui's famous Chaweng Beach - a beach that has produced several serious stings and a fatality in 1999. This is not typical of Australian habitat as reef's are usually no-go areas but perhaps they've adapted differently here.
Normally a lethal box jellyfish will hunt for small fish and prawns in shallow sandy bottom beaches within close proximity to a river or creek mouth/estuary. The water is often somewhat cloudy and from all reports you cannot see the jellyfish who are almost transparent. The beach at Koh Lanta where Moa Bergman died in 2008 is typical as is the Koh Mak beach where Lewis Jones nearly died late-2007 - I would not swim at either without a stinger suit!! No way!!!
Numerous people claim never to have seen a Box Jellyfish in Thailand - divers who've worked the waters for 10 years, visitors who return time and again. The truth is they are out there but they are incredibly difficult to see and tend to breed in non-touristy areas before dispersing though no-one knows at this stage where they come from. In Hawaii for example their box jellyfish arrive in a very predictable lunar-determined timeframe but no-one knows from where exactly they come.
So, while people may claim not to have seen them it comes as no surprise and does not mean they're not around. We know they are because they are stinging people in both the Gulf of Thailand and Andaman Sea.