Megafauna Magic Returns to The Similan National Park

Whats Going on?

The cooler waters mentioned in our last blog continued into the start of February. Thermocline’s reading as low as 22 degrees C in places washed through the Similan and Surin National Parks. Although a bit chilly they certainly appear to be attracting a whole load of rays, sharks and recently mantas, as well as keeping the coral happy. So here what we have been up to in the Similan and Surin National Parks.

Similan Sea Fans

Monitoring The Parks

We welcomed the Phuket Marine National Park Operation Center 2 aboard Mv Hallelujah.  They carried out a number of checks around the Similan and Surin National parks dive sites. 

Its very encouraging to witness first hand the work that is happening with in the parks. Testing the water temperature and Ph levels at various places and depths to monitor how the water movements etc are effecting the reefs.

Also photographing specific areas of reef on a time basis, once, twice a year etc to look for growth, natural and unnatural damage.   

Science happening
Water Sample Analysis


The Return of the Megafauna

As we approached the end of January we started to hear of a few sightings on mantas around the Similan’s. This is always an exciting time of year for us, especially as last year manta sightings started later last season. For me personally it was the 6/2/20 before I got to see one of our big black flappy friends.

Manta 1
One of our Id Shots captured on board the Mv Hallelujah

Since then, we have been very lucky and seen mantas regularly so far this month at Three Trees, Koh Bon and Koh Tachai both on board our Similan Liveaboard the Mv Hallelujah and our Similan day trip the Blue Dolphin.

Although huge in size mantas are certainly very elusive so every encounter is very special. We hope they plan on sticking around  as we continue to try and learn more about Thailand’s manta population.

The MMF and MantaMatcher

Continuing our support of the Marine Megafauna Foundation and its citizen science project “MantaMatcher” our guests and staff have collected and uploaded several ID shots in the last few weeks.

Photo id Manta

These ID or belly shots contribute by helping us to learn more about Thailand’s manta ray population.

From photos alone it is possible to identify a manta and then gather valuable information.

  • Sex
  • Age
  • Injuries or scarring
  • Visibly pregnant

How Does it Work

A sophisticated algorithm is used to match manta identification photos automatically. The algorithm works like facial recognition software for manta bellies. By automating much of the identification process researchers can match mantas regionally, and even globally, with ease. Researchers will ultimately be able use sightings data to determine the abundance, trends, movements, and population structure of manta ray populations at individual aggregation sites across the globe.


 Up North “Surin and Richelieu Rock”

As we all know Richelieu is often referred to as the jewel in Thailand’s diving crown. It always certainly puts up a very good fight for the title.

This year conditions from Christmas till now have been a little different. The viz is defiantly lower than in previous years and the temperature has been the same as in the Similan National Park. However the diversity of life is still plentiful.

Whether it big large schools or trevally, fusiliers, rainbow runners that you are looking for or the smaller macro life. Richelieu has continued to show it has something for everyone.

Recently we have been seeing marble rays, loads of Kuhl’s sting rays and shovel nose rays or guitar sharks as they are sometimes called.

Marble Ray

This rather large marble ray (shown above) was seen cruising around Richelieu often on the edge of the where the cooler and warmer waters met.

Shovel Nose Ray

Down in the sands around the north of Richelieu this year has been a favorite spot to find these beautiful shark rays or guitar sharks as they are also known.

We were also lucky enough to witness 100’s of Kuhl’s stingrays moving just above sands for just a few days. A sort of behaviour I haven’t seen before. Truly memorising to watch a “Blue Planet” style display.

We are very much looking forward to the rest of the season. This year has turned up some great dives and quite a few surprises so we will be keeping our eyes peeled.

Looking Forward

We have some great offers on for the end of the season.

Hallelujah surrounded by marine life Email us here at Big Blue Diving Khao Lak to find out more.