Underwater in Thailand’s Similan Islands

Totem's transom
I might have maligned the Similans a bit by pointing out that the coral is kinda dead, the diversity is lacking, and the tourists outnumber almost everything else. It’s true, but it’s not the whole story. The truth is that we still had a great time and saw some amazing things underwater. It’s just not the in-your-face marine lushness that we’ve been completely spoiled by in the past.

The first and most striking aspect was how crystal clear the water is- really, the clearest we’ve seen since French Polynesia. The viz dropped a little at the northern end, but apparently that’s partly because we’re still at the front edge of the NE monsoon season- it will be better still in January.

The island is a string of nine are granite heaps (Similan is from the Malay word for nine, sembilan), about fifty miles northwest of Phuket. The big boulders of an islet behind Totem’s transom above? They give you a sense for the shape of the underwater environment as well- much of the time, what we’re swimming through and around looks like this image of Niall below. The swell coming through rocks and crevices could make things a little interesting upon occasion, but we only had a few barnacle scrapes.

boulder swimming

Another really crazy, I have no idea what the heck it is, underwater critter were these transparent batwing things. I have no idea how to even categorize it. Can you see it in the image below? Anyone with more marine smarts than we have who can ID? The boomerang-like shapes averaged about a foot long, and an inch or two tall. There was a school of hundreds of these that came through, and just kind of bounced off our bodies as we swam against the current that carried them along. Update: thanks to the comments on our facebook page from a couple of marine biologists + former cruisers, this cool little critter is identified as Cestum veneris, a Ctenophore- “which are related to the jellyfish (cnidarians) but in their own phylum. They differ by their mode if propulsion – they use thousands of microscopic “combs (elaborate cilia) to create water currents – as opposed to the pumping action of a jellyfish.” Thanks Emmanuelle and Mike! 

what IS this thing?!

We saw more holothurians (sea cuccumbers) than we’ve seen in a long time. Not just more, and a variety, but some really big ones- see the shape next to my body below?

HUGE sea cucumber

These are sought after for the Chinese culinary market, and completely fished out in may places we visited. If you are wondering what they taste like, let me just save you the experience and say- it’s gross, don’t. You’re welcome.

I was so excited to even see a fan, that I took a picture of it. It’s really unremarkable, except for the pathetic fact that it was so very much alone.

fan coral
There weren’t a lot of soft corals, either, so the few spotted naturally stood out. Look at this beautiful thing! I think it’s a bubble coral.
Dan and I came back from one expedition raving about all the spider conchs we’d seen. The striking difference? All his had a mollusck inside, and all mine had hermit crabs. There were a lot of hermit crab conventions happening on the sea floor. I swear these two were having a convention.
hermit crab convention
fishA lot of the schools of fish were hanging out in about a 12″ range from coral heads, like this one at right. 
They just look like bait to me. They look like bait to a lot of fish, I think. Pretty, though, and curious. It’s fun to swim through them. Does that make me an irresponsible snorkeler? I hope not!
The sheer volume of wee little baitfish schools everywhere was one of the most consistent impressions of the Similans. Almost any panned-out photo you look at, they’re the speckles in the distance or the blob that makes a coral head’s otherwise sharp edges appear a litlte fuzzy.

It seemed to be the nursery for many fish. Check out this crazy little translucent one: it was about the size of my pinkie finger. That’s it. Teeny. There were a pile of them right next to Totem.

crazy tiny thing
I wonder if the juveniles are just finding this a good place to get bigger, so they can go out to the Andaman and get plucked off in mass by the wall of fishing boats? Yes, cynical me. But it’s true. You could always count a half dozen boats during the day, and many many more strung out along the horizon at night. No way were they staying outside the 5-mile no take zone that’s supposed to exist around the park. Sad.
The occasional pelagic fish managed to make it through the gauntlet. One of the cooler fish was this giant barracuda. It was just hanging out on the bottom, minding it’s own business, not wanting to bother anyone. Just… sitting there. Niall went down to take a look, and it was barely fazed. Besides the big (and sorry, but fuzzy) ‘cuda in this shot- check out the gazillion little speckles. FISH. There were so, so, so many little fish everywhere around the Similans.

scoping out a giant barracuda

These four trevally spent most of the day around a coral head that was under Totem. It was FULL of tiny fish- see the fuzzy stuff in the photo? Fish. They move in a school almost like they share a brain. Most of the time, the trevally were just acting cool, but every once in a while one of them would blast through the school for a little snack. It was wild to watch.

trevally on the hunt
Gratuitous anemone shot, because clownfish are just so dang cute. Yes, I’m a sucker for the whole Nemo thing, fine, laugh at my expense. I’ll just leave you with that cuteness.

anemone fish
If you’re reading this on the SAILfeed website, you’re tossing change in our cruising kitty. Thank you!

8 Responses

  1. I have gone scuba diving in Thailand near Koh Phi Phi and in the Gulf of Thailand around Koh Tao and both of those places were better than the photos here for both coral and creatures. When I was last in Thailand I was disappointed that I wasn’t able to get to this area to dive but if your photos are indicative of what is there then it doen’t look like I missed much 🙂

    1. Patricia, I’m very curious to know what year(s) you were diving near Phi Phi and in the Gulf. I don’t know much about Gulf diving but the word was Similans currently are supposed to be superior to Phi Phi. I’m interested to consider local impacts in the last few years in one location vs the other. Thanks!

    2. I was diving in those places in April 2010. I was on Koh Tao for a destination wedding. The brides sister was working as a dive master there so set everything up for the wedding and for diving afterwards at the resort she was working at on a small island just off the coast of Koh Tao called Koh Nanyuan. I did about 12 dives in the area. Then I took off for Krabi and did dives out of Ao Nang. I did a “super” day dive of three dives near Phi Phi, the King Cruiser wreck dive, Shark Point drift dive and Anemone Reef. I also did two dives closer to Ao Nang. Lthough there was lots to see here I thought the diving was a bit better in the Gulf of Thailand at Koh Tao.

    3. Patricia, thanks so much for your reply! I’m hoping to do some diving around PhiPhi in another month or two and will post about it once we have a chance to experience it ourselves. I’m told that warmer water temps in 2010 in the Andaman Sea near Phuket resulted in a lot of the coral dying, here and in the Andaman islands. I wonder if that explains some of what I’m seeing vs what you experienced? I’ll readily admit that I’m not terribly informed about what occurred, although I’m interested in learning more! I hope we can do some Gulf of Thailand diving too, although it’s not clear we’ll get over to that side of the peninsula. Thanks again for all the information!

  2. The water was quite warm when I was diving, in Koh Tao the water temperature was 32c! I can’t remember what it was around Phi Phi but it was probably close to that. The current was very strong at Phi Phi, the dive master said something about the time of the month and the moon. Also that area is where water drains out toward the Andaman sea. Made for some interesting diving 🙂 but the drift dive was fun. Also did a night dive around Koh Tao.

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