Changes in the Similan National Park

Our Season So Far..

So with the festive season upon us, we take a look back at the first part of the season.

Similan National Park News

All in all a productive start to the season diving wise. Are we are starting to see changes in the Similan National Park? We think both around the park and in the water.

A new Similan National Park Chief has been appointed and seems keen on engaging the local dive community. Starting with conversation about what’s best for the future of the park. If this is the start of new era of communication then the prospects are very good for both the park and the businesses that operate with in it.


This year more than ever before we are noticing more thermoclines. Bodies of slightly cooler water on dives. When we say slightly we mean as low as 21 degrees on multiple occasions.

We are in the camp of this being a good thing, once we upgraded to some neoprene from board shorts.

These bodies of water are often nutrient rich and great for the reefs. They replenish the corals with nutrients they normal hold in the deeper water. Nutrients such as potassium, nitrogen and phosphorus that build up when aquatic animals die, sink and then decompose.  West of Eden, North and Christmas Point, Koh Bon and Tachai in particular this year have had their fair share of thermoclines.

This has a knock on effect as the healthier the reefs the more inhabitants it can support. Small reef fish will go about their day to day routines as the coral reef will offer some protection from more predatory species. It won’t stop them coming in for a hunt. This is probably why we are starting to see more sharks around.



Not just on board the  MV Hallelujah or the Blue Dolphin but general reports from the Khao lak dive community indicate increased sightings in sharks and rays. We have had a few manta sightings early on this year from Koh Bon and Koh Tachai, and alongside these repetitive sightings of shovel nose rays, Jenkins whip rays and even a few eagle and marbled rays.

In recent weeks whale shark sightings at Koh Bon and Richelieu, along side white and black tips, and nurse sharks in the Similan National Park it does seem to suggest that Similan is recovering.  Fish stocks appear to be healthy in number and diversity with many species occupying the waters all over the park.

barracudasNew Year

Moving into the new year and the high season what should we be looking out for.

As the number of visitors to The Similan National Park will increase over the coming few months, we will be keeping a close eye on the conditions and seeing what happens.

Obviously we hope for more megafauna especially the mantas. At Big Blue we continue to support the marine megafauna foundation and the use of MantaMatcher , the citizen science platform.

A great way for our guests to be able to see their photos have a positive effect and help us learn more about the manta populations of Thailand and Myanmar.

Ric marks his tenth year since he first met Dr Andrea Marshall and has been involved every year since. Boots has recently volunteered to help them as well. They are always happy to talk about the work the MMF is carrying out in Thailand, Myanmar and the rest of the world.

Unfortunately last year towards the latter part of the season we started to get a few mantas with very noticeable injuries.

Many carrying huge scars and damage from fishing gear and shark bites. More than ever we now need to learn everything we can to help protect and manage these magnificent creatures and their populations.

manta showing a lot of damage

We will keep you up to date with the latest developments from both the Similan and Surin National parks on our facebook page.

To finish we would like to wish all of you a very Merry Christmas and a happy new year. We hope to see you all again very soon.

Christmas on Similan Beach