Sunday, August 21, 2011

Finally! Galloping sea star at Semakau!

After a long time of trying to search this elusive sea star, James fulfilled my wish by finding this Galloping sea star (Stellaster equistris) last Sunday during our trip to Semakau.

This is the special sea star that I've always wanted to see. It has been sighted at Sentosa twice before but I always fail to find it there. Haha!

One of the identifying features of this star is that it has short stumpy spines that are well spaced apart. From far, it is quite well camouflaged and can easily pass off as a juvenile Common sea star (Archaster typicus).

The underside of the sea star is much prettier. It is in white with some rounded patterns near its mouth.

The story of how this star was found is quite interesting. James first found another rare star, the Eight-armed sea star (Luidia maculata) and he only told me much later about the find. He tried to go back and find the sea star for me to have a look but to no avail. And while searching hard around the vicinity, a rarer star "popped" out and that is this galloping star! Haha!

Therefore, as what Ria later said, everything happens for a reason. :)

We explored my most favourite part of the Semakau shores, the southern part. The substrate and habitat here is quite similar to the northern shores and more closely alike to Cyrene Reef where there is a combination of northern and southern creatures.

Like many of our northern shores, this southern Semakau shore has many elegant Haddon's carpet anemones (Stichodactyla haddoni).

Among the bed of blooming Sea lettuce (Ulva sp.) seaweed (which is common on our northern shores as well) is this juvenile Giant carpet anemone (Stichodactyla gigantea).

When the Giant carpet anemone grows to become more like giant, or bigger, you can find many False clown anemonefish (Amphiprion ocellaris) swimming among the tentacles.

I stumbled across this uncommon sea anemone that is probably the very long Actinoporus elongatus.

Wow, this is one of the rare moments where I can take photo of a nicely expanded Fire's anemone (Actinodendron sp.). In fact, there are quite a number of these anemones on the Southern part of Semakau.

Looking like anemones from part, this is actually the underside of a juvenile Upsidedown jellyfish (Cassiopea sp.) that prefers to be upside down because they harbour microalgae on their tentacles to photosynthesize. Very pretty right?

One of the reasons why I like this shore is because it is rich with echinoderms. I did not expect to find this Feather star (Order Comatulida). Therefore, it came as a pleasant surprise for me. This feather star is quite pretty and does not look like those that we usually see.

We also came across several types of sea cucumbers. Such as this unknown small sea cucumber that looks a bit like the Garlic bread sea cucumber (Holothuria scabra). Is it really one?

Another strange looking sea cucumber would be this one found by Ria. I do not exactly know its identity.

Could the sea cucumber from the previous photo be a juvenile of this Remarkable sea cucumber (Holothuria notabilis)?

Though this Long black sea cucumber (Holothuria leucospilota) can be extremely common on certain rocky shores, it is not often seen at Semakau. I think this could be my first time seeing it here.

Among the soft substrates, one would expect to also find the Ball sea cucumber (Phyllophorus sp.). After Ria asked if I saw it, this sea cucumber was found later during the trip.

Ah hah! A snake! I have not seen snakes on the shore for some time already. This is the Dog-faced water snake (Cerberus rynchops) which is common in mangroves. It is no surprise to find this fellow here as the shore is situated right in front of the mangroves.

Among the seaweed, there are quite a number of intriuging looking ascidians that are poorly understood on our local shores.  This ascidian is in black and orange- a nice combination of colours!

Here is another organism in orange, in fact bright orange throughout and speckled with white dots. This is the stunning Little ruby flatworm (Phrikoceros baibaiye)! It is only my second time seeing it if I did not recall wrongly.

An uncommon snail that we have came across will be this Margined conch (Strombus marginatus sowerbyorum).

There were quite a number of slug sightings! Such as this Denison's nudibranch (Dendrodoris denisoni).

James found this tiny Gymnodoris nudibranch (Gymnodoris sp.) that looks different from the usual ones that we see on our shores. It could be Gymnodoris citrina instead of the more common Gymnodoris rubropapulosa.

What is this pinkish thing on the ground? This is actually an egg ribbon of a nudibranch.

Not too far away, I saw another egg ribbon, this time in white. Hmm it looks familiar!!

Indeed I was correct. It belongs to the very large Forskal's sidegill slugs (Pleurobranchus forskalii). This pair is probably doing it on the shore. We saw many more of these slugs on Cyrene Reef recently.

Of course who doesn't love slugs? We all gathered to take nice photos of these snails without shells. Haha.

Last but not least before I left the shore, I saw this Ornate leaf slug (Elysia ornata) nearby. Though it is not exactly very green, it is still beautiful!

A small gang of us later went to explore the mangroves. Read more about more adventures here in Ria's wildshores blog.

Anyway, she found this fish trap with two large Mud crabs (Scylla sp.) deep inside the mangroves. I wonder how the fishermen got in to lay the traps and whether will they remember to go back and retrieve the traps. 

After releasing the poor crabs, they became more active and looked happy to be back at home.

On the way out, I had a look at the flowering Avicennia marina. Read more about this special mangrove tree of Semakau here at Ria's wildshores blog.

It was definitely a fruitful trip and I look forward to come back and explore this part of Semakau more properly. :)

More photos of the trip here:

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