Tuesday, October 30, 2007

Discovery @ Semakau on 28 Oct 2007

Thirtieth Discovery Posting:

Entry @ 01 Nov 2007: Changed the date of the walk, it should be in Oct, not Sep. =P. Thanks to Ron for pointing it out)

On Sunday (28 Oct 2007), a batch of Semakau guides (myself included) were out at Semakau for exploration. With a plan to explore the mangroves in mind, we arrived on the island before the low tide and this was the scene that greeted us as we emerge from the usual forest trail (picture below).
I can't seem to find a picture for comparison but if it was low tide, the water you see in the foreground would have receded towards the background.

The first 'discovery' along the shores was a perepat tree (picture below)
Here's a shot of its cone-shaped roots (picture below)
Discovery Note:
1. They can grow up to 20m tall
2. Found at the front of the mangrove belt and usually on sandy soil.

3. Its wood can be used for firewood, house building and clogs.

4. For more information, click here.

The sight of rubbish on our shores has always been frowned upon. But from time to time, we do get something which puts a smile on our faces first before a frown. Here's one example (picture below).
Smiles on our exploration walks have always been a regular sight. Here's Angie with a broad smile despite the condition she was in (observed her legs, i know they are a distract, but try to spot her foot if you can). Oh, by the way, i was the one who asked her to 'smile' for the camera (picture below). =P
And as we walked along the shore, Ron was turning over rocks almost all along the way, i was wondering what was he looking for, therefore when he gave a cry of "yes! I found it!". I moved towards him as quickly as i could.

And i saw the second 'discovery', a cryptic rock star (picture below), a new sighting for me!
Underside of the cryptic rock star (picture below).Discovery Note:
1. They can have 4, 5 or even 6 arms!

2. They have a mottled, but variable,
colouration which serves as camouflage, hence the name of cryptic rock star.
3. They are rare as they need undisturbed rocky shores to live at.

Third 'discovery' is a plant found near sea shores, which i've seen along the coast of Chek Jawa and Sentosa, the sea lettuce (picture below).
Here's its beautiful and unusual looking flower(picture below). Discovery Note:
1. They have large and waxy leaves .
2. The waxy leaves are there to prevent water lost, which is important, as the temperature near the sea shore can get really hot...

Not far away, Angie and another friend (i can't remember your name although i 've seen you twice, so sorry.) spotted a baby horseshoe crab (pictures below), fourth 'discovery' and look at its size compared to a twenty-cent coin.Discovery Note:
1. Horseshoe crabs have known to 'roam' the earth since days even before the dinosaurs was around, so scientists calls them 'living fossils'.
2. Although they are called horseshoe crabs, they are not related to crabs. They are actually more related to spiders and scorpions.
3. There are two types of horseshoes crabs which we can find in Singapore, the mangrove one (circular tail) and the coastal one (the trianglar tail)
4. The tail is not venomous and is not used as a weapon. It is merely used as a lever to right itself if it is overturned. If you see an upside down horseshoe crab struggling with its tail waving around, do give it a helping hand. It will not hurt you.

As we continued to wonder along the shore, we soon spotted a whole lot of seashore pandan (picture below), fifth 'discovery'.And they were fruiting, here's one of them (picture below). Don't it look like a pineapple? =)Discovery Note:
1. This is also called the Seashore Screwpine.
2. It is a formidable plant to encounter as it has dense clusters of long, stiff leaves armed with three rows of short spines.
3. The compound fruit resembles a pineapple and are dispersed by water.
4. Like many other screwpines, the leaves are used to make mats and baskets.

Side note:

During the construction of the land fill, NEA had to clear off mangrove forests, but an effort was made to replant mangrove trees. And here's a photo to show the replanted mangrove trees (picture below) Even after purchasing a 'swimming' camera for about a month, i still had not tested its 'swimming' ability, so this was a good day to let it swim. Here's a underwater shot i attempted (picture below). But what was it i was photographing?Sixth 'discovery', the sand star or better known as the common sea star (picture below).
Discovery Note:
1. Although called the common sea star, they are now rare due to over collection and habitat lost.

Just a few steps away, i saw this (picture below). Want to guess what are they doing? read on...
Discovery Note (Warning: Sex Content):
1. This is a 'mating' position for the sand star.
2. The 'mating' position for the common sea star works like this: the male will be on top of the female, their arms in a formation as in the picture.

3. But they do external fertilization, which means their sexual organs don’t come into contact and the closeness is to increase the chance of fertilization, when they release the eggs and sperms into the water.

4. This 'mating' position is consider unusual in the world of sea stars, as only the common sea star and one other related species is known to “mate” in this way.

And for the first time, i saw sand dollars at Semakau. Seventh 'discovery'!
Discovery Note:
1. Living sand dollars are coated in fine, harmless spines that made them very velvety.
2. The spines are movable and are used to dig into the sand or move around.
3. The dense layer of spines also helps to keep off sand and silt so there is a flow of oxygenated water across the body.

As we wondered further into the unexplored parts of Semakau, we heard a shout from Helen, "Wa!
", and all of us were very soon standing very near to where she was. Eighth 'discovery'! Baby knobbly (picture below)! Side Note:
Currently, i am 'tasked' to do a mini project to monitor any baby knobbly found on Semakau. Thus do look out for a posting soon all on this baby knobbly. =)

And in a gigantic carpet anemones along the trip, two clownfishes were spotted. Ninth 'discovery'! (pictures below)Discovery Note:
1. The clownfish have a symbiotic relationship with sea anemone.

2. They have a mucus covering that protects them from the sting of the sea anemone's tentacles.
3. This mucus prevents them from being harmed, and allows clownfish to live in sea anemone.

4. Clownfish are hermaphrodites (they develop as males first and mature as breeding females or ‘change’ into a female if there are no females).

5. More information? Click here.

How do we tell apart a true and false clownfish?
Wish to find out? Click here.

After exploring a bit, we decided to head back to our usual guided walk area for a look. I was ahead of everyone as i wanted a sight of the adult knobbly sea star as it might be several months before we return to Semakau. But instead, i found three clownfishes living in a gigantic carpet anemone around the area where we usually have our walks. I tried to take a video of one of them swimming, but as i couldn't managed to focus well enough, the outcome is as such...

By the time, i finished videoing the clownfish, i had to turn back, as the time to leave was near. It was a pity that i couldn't find the adult knobbly, but nevertheless the sight of the cryptic sea star and a total of five clownfishes really made my day! =)

Thanks to Luan Keng for organising this trip and everyone else who came and made the walk another light hearted and enjoyable one! =)

Click here to read Tidechaser Ron's blog entry on this same walk.
Manta Samson's blog entry? Here it is!

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