Monday, October 29, 2007

Exploring Semakau on 28 Oct 2007

I heard the news reader on the radio saying it would rain in the afternoon just as I was leaving my place yesterday.

Shucks! Don't tell me every time we go for our own exploratory trip, it will rain!

When we reached the shores, the sky looked strange - half of it was blue sky, the other half covered with dark clouds.


Anyway, we went on with our exploration. The tide was still quite high, as we decided to come earlier to take a look at the mangroves which we had often neglected.

One of the first few animals we spotted - a cute little ladybird on a sea hibiscus leaf.

A perepat tree has hundreds, if not thousands of cone-shaped roots. I was always extra careful whenever I walked among these roots. Can't imagine what will happen if I were to slip and fall. In fact, most of the time I try to avoid wondering among perepat roots.

Many of the seashore pandan were also fruiting. The fruits always remind me of pineapples. This is a very useful plant - the leaves were sometimes used to weave into basket or mats, and the fruits were used by fishermen as floats. Essential oil extracted from the male flower is used by North Indians for cooking or even as a perfume.

My attention soon drifted to the rocky areas near the mangrove. According to the "Guide to Sea Stars & Echinoderms of Singapore", a type of sea star which I've only seen at Pulau Tioman so far, Cryptasterina sp, can be found on Semakau's rocky shore. And Luan Keng told me that she had seen it before!

Thus, one of my main objectives for this trip was to find it!

I started randomly turning over rocks along the shore as I walked towards the western end of the intertidal area.

And finally, after searching for about half an hour, I found them!

At last! And now, the types of sea stars we've seen on Semakau in the intertidal area add up to 5! We have the sand-sifting sea star (Archaster typicus), knobbly sea star (Protoreaster nodosus), cushion star (Culcita novaeguineae), crown rock star (Asterina coronata), and now, the cryptic rock star (Cryptasterina sp.)!

I managed to find 6 or 7 of them before I stopped flipping over every other rock. The colour of the ones I found was somewhat different from the ones I've seen at Tioman and in the guide book though. So I'm not sure if it's just a colour variation or a different species.

It soon started drizzling, but fortunately it wasn't that bad and we managed to carry on with our exploration.

Finally, we reached the far end of the mangroves at the mouth of the river.

This was certainly a special moment to remember - my first time coming to this far end of Semakau!

And on the rocky area near the end of the stream, I found a giant top shell, ultra well camouflaged among the rocks. I've seen giant top shells several times before on some of our southern islands, but this is the first time I've seen it on Semakau!

Following the stream, we reached a seagrass meadow and several sandy patches here and there. I saw a shell moving and decided to pick it up. It's a striped hermit crab. But wait! There's something else...

There's a chiton at the opening of the shell! It's that oval-shaped thing in front of the hermit crab's pincers. Can you see the eight plates on its back? A chiton is a mollusc, related to squids, clams, and snails! This was the first time I saw a chiton in Singapore! Heard from Angie that she often saw them while diving though. The last time I saw one was in New Zealand. They were much bigger there though.

My second objective of this trip was to find the sand dollars. We knew that there were sand dollars on Semakau from Zeehan, but we were not sure where.

As we walked further out into the seagrass meadow, I came across a sandy patch and saw many circular prints on the sand. So, here's where they were hiding! And there were so many of them too!

And just nearby, there were lots of sand-sifting sea star. This one only has four arms, unlike the usual ones with five arms.

And just then Luan Keng shouted something and caught everyone's attention.

She found a juvenile knobbly among the seagrass! (Note: Pai seh, found out from July's blog that Helen was the one who found it, though Luan Keng was the one who shouted to me.) This was the second juvenile knobbly we'd seen on Semakau. The previous one was found during the public walk. Too bad we wanted to explore the reef edge, and thus did not spend more time to look for more of them. I'm sure there will be many others in the seagrass lagoon.

And heading towards the reef edge, we spotted several sea cucumbers.

Two shorter ones on top were the stonefish sea cucumber (L) and the dragonfish sea cucumber. The longer ones below were a synaptid sea cucumber (L) and a long thorny sea cucumber which we'd never seen on Semakau before! It's probably as long as, if not longer than my arm!

We also saw a few carpet anemones with nemos. While I didn't managed to get any clear photos of the nemos, I got this instead:

An anemone shrimp in a cup-size carpet anemone! Looks really cute :)

We also found a grumpy looking moon crab among the seagrass.

And this discodoris nudibranch was the only nudibranch I saw for the day.

Nearer to the coral reef, I had another special find - a giant clam! It hasn't grown that big yet though, perhaps about 15cm long.

There were several noble volutes too, and one of them appeared to be feeding on a spiral melongena. Felt so pai seh because I didn't know it was feeding and picked it up. It dropped the snail which was engulfed in its foot immediately. It appeared that there was hardly anything left in the melongena shell though, except a bit of blackish soup. I quickly put the volute back down on top of the mostly eaten melongena. Hopefully it would continue its meal.

And just not far from the volute, 2 squids. They look really cute when they were hunting. They swam near the surface of the water, with their arms opened up to two sides, looking like the blades of a pair of scissors, and their two tentacles tried to snatch any passing fishes. But guess they weren't too successful, probably because I was there watching with my torch shining around.

All too soon, it's time to go back. Semakau was just too big, and I think I had hardly even covered 5 percent of the intertidal area!

Sure want to come back here again to explore!



Mountain & Sea said...

Wow, Semakau still have a lot of surprises. Particularly those sea stars that you have found. Have not seen them before.
Thanks for sharing.
Should be there if not for the flight I have to catch.
See you.

Ron Yeo said...

Yup. But there's always the next exploratory walk to look forward to! :)