Friday, May 29, 2009

Discovery @ Sekudu on 27 May 2009

Ninty Fourth Discovery Posting:

This is a little late posting as I was busy with work the past two days. Anyway, despite having work commitments, I still managed to squeeze time to visit Sekudu or otherwise known as Frog Island. The answer to why this small island, yes, it is a little island about the size of a football field and is located about south of Chek Jawa of Pulau Ubin, is called Frog Island will be made known later.

In this posting, I will highlight some of the MANY organisms which my friends and I have seen during the trip.

'First discovery' is this ghost crab (picture below).
Discovery Notes:
1. The logic behind their name is that they are more commonly sighted during the night.
2. Another reason is that they move really fast, or one could say that in a glance of eye, they can disappear in front of your eyes.
3. Read more about Ghost Crabs @

Our second 'discovery' is not one but two blue dragon nudibranchs. To be truthful, I believe there were three sightings of blue dragon nudibranch. However, i only got photos for two of them (picture below).
Discovery Note:
1. For protection, some nudibranchs produce distasteful substances, toxins and acids. However, not all nudibranchs can do that. So as an alternative, they kind of make use of the food they eat for protection.
2. The blue dragon nudibranch for example, eats hydriods. And it is important to note that hydriods possesses stings that can hurt other organisms real bad upon contact. So when eating the hydriod, the blue dragon nudibranch also 'take in' the stings and 'transplant' it on their bodies as a form of self-protection.
3. The blue dragon nudibranch can also 'take in' zooxanthellae (algae) in their bodies. The zooxanthellae when photosynthesising can share its food while the blue dragon nudibranch provides it a home.
4. Find out more @

Third 'discovery' is a leaf slug (picture below).
Discovery Note:
1. Leaf slugs can also 'take in' things from the food they eat and make use of them.
2. Leaf slugs usually eat seaweed and they are able to retain the choloroplasts (the part which contains chlorophyll). These choloroplasts are able to continue photosynthesising in the body of the leaf slug and provides any extra 'food' to the slug.
3. The choloroplasts found in the bodies of leaf slugs in one main reason why they are mostly green in colour.
4. Read more about them @

Next up, fourth 'discovery' are two carpet anemones (picture below). There are actually quite a number of carpet anemones on Sekudu. This is great as it is a sign that Sekudu is also recovering from the great flood that affected Sekudu and Chek Jawa in Dec 2007/Jan 2008. Anyway...
Discovery Note:
1. For self defence and preying purposes, carpet anemones have stinging cells in their tentacles which will release or 'shoot' small 'needles' when upon contact. So I won't really advise you to touch them although our skin might be 'thicker' than most marine creatures. This is to prevent you from getting stung.
2. They lack an anus, so they split out any indigestible food through its mouth.

Readbody tphy over.

Fifth 'discovery' is also an anemone. But this is a swimming anemone (picture below).
Discovery Note:
1. This anemone often looks like a ball of tentacles and it doesn't have a long body column that is buried in the ground like the carpet anemones or peacock anemones.
2. Instead, it may be perched on seagrasess. This anemone can swim by undulating its tentacles!
3. Read more about them @

Sixth 'discovery' is another anemone and this one is a peacock anemone. Another anemone which can be found in numbers on Sekudu (picture below).
Discovery Note:
1. To see their full beauty, you will need to see them in a certain depth of water, like above.
2. The long small things around the ring of the anemone are actually tentacles, and there are two types of tentacles, one on the outer ring while the other on the inner ring.
3. The tentacles on the outer ring gathers food (plankton) are called the marginal tentacles and the tentacles on the inner ring (which are usually shorter) are called oral tentacles is for manipulating food into its mouth located in the center.
4. Their 'home' is a tube found below the mouth area, therefore they are also known as tube anemones.
5. Read more about them @

Seventh 'discovery' are two different types of stingrays (pictures below).
First up is a mangrove whip ray.
And the other is a blue spotted stingray.Discovery Note:
1. The position of the eyes allows a stingray to see almost behind it.
2. The gills and mouth are found on the underside of the body.
3. It doesn't really have teeth—instead, the mouth is outfitted with two food-crushing plates.
4. Rays dart away when they sense trouble approaching. When caught off guard, these fish fend off predators with a flick of the tail, which is equipped with two venomous spines. Since its tail is so long, a stingray can even strike at animals directly in front of it.
5. The large tail spine of a stingray is dangerous and even deadly. The barbs in the tail are so large; people have bled to death from a sting. However, they will not sting unless you handle or step on them. So never handle them and allows follow your guide's trail on a guided walk.
6. Read more about them @

Eighth 'discovery' should be a peacock solefish (picture below). (*Newly added*)According to Ria, this might be a large-tooth flounder instead as its tail fin is separated from the dorsal and tail fin. Thanks Ria.
Discovery Note:
1. The large tooth flounder is almost as flat as the peacock sole.
2. To me, it is not easy to tell them apart as I am not familiar with fishes.
3. However, a second examination via photos could help us with its ID. So it is important to take photographs of any sightings if possible.
4. Read more about peacock soles @
5. Read more about large tooth flounder @

Ninth 'discovery' is a sponge crab (picture below). Discovery Note:
1. They are called sponge crabs as they usually have a living sponge on its top carapace.
2. It is not born together with the sponge if you are wondering. The crab uses its pincers to snap out a cap out of a living sponge to fit it over its body.
3. The purpose of this is for camouflage and protection from its predators (since sponges usually leaves a 'bad' taste).
4. To read more about it, visit

To top of these sightings, we also had a really starry morning. This is because we saw a number of sea stars during this trip (pictures below). Now before ending this posting, let me explain why Sekudu is also called Frog Island.

One reason is because that there is a rock on the island which looks like a frog (see the picture below).There is also a legend on this. It goes something like this:

Long before your time, 3 animals, an elephant, a pig and a frog lined up along the coast of Changi in a swimming race from Changi to Johor.
As they raced, the frog drown halfway through the race (I'm still wondering why, as I feel frogs should be better swimmers compared to elephants and pigs) and thus formed Pulau Sekudu.
Well, the elephant and pig didn't complete the race as well, in fact they drown a little further up from the frog drown, and so the two animals formed the island of Pulau Ubin.

This was a really great trip. Thanks to LK and R for organising and all others for making this trip another FUN trip. =D

Forgot to add that you will need a permit from Nparks to visit this Island. Thanks CH for the reminder. =D

By KS:
a) Dollars and Sands of Sekudu:
b) Back to froggy Sekudu:

By R:
a) Enchinoderms of Sekudu:
b) Sekudu on 27 May:

1 comment:


Haha, sorry to be so lohsoh, but since most of you forgot to mention about the permit in the blogs; here I go again:

Just a note to the readers, the access of this island is restricted and permit from Nparks is needed. :o)