Jul 3, 2008

Kiasi Krab on Changi

3.30am and we're back on the shores, this time at Changi for the super low tide. This narrow but favourite shore of ours is just teeming with life!There are at least five creatures visible in this photo, can you spot them all?OK, some of them are really tiny like the snapping shrimp and little hermit crab, in addition to the bigger sand star, peacock anemone and brittle star.

The seaweeds are in fact, crawling with all kinds of tiny creatures.There countless tiny crabs. And I saw one tiny sea urchin. This is one reason why we should avoid stepping on thick growths of seaweeds.

Here's another crowded photo with another five visible animals.
Besides the tiny little fishes, it's easy to overlook the big spiral melogena snail whose shell is well camouflaged, Its little black siphon is sticking out of the shell tip.

Here's another photo of what seems to be big sea anemone and sotong.But the sotong turns out to be an octopus!It had arranged its arms around its large head! Here he is spouting water.When he decided to move, he looked more obviously like an octopus!

The octopuses on our Northern shores look different from those we see on the Southern shores. The Northern octopuses have big heads (relative to their shorter arms) and don't seem to change their skin textures to become spikey or 'hairy' like the Southern octopuses. We still don't know the identity of both of these kinds of octopuses.

Peacock anemones seem to be a favourite hangout for other marine life. Around the tube of this retracted peacock anemone were lots of little black spirals of phoronid worms. And a little bristley brittle star was nestled among them.

For some reason, this morning I saw at least three peacock anemones with elbow crabs next to them.This peacock anemone has two elbow crabs nearby. The crabs are well camouflaged: there's one on the upper right corner, and another in the lower middle portion of the photo.

Another fascinating animal is the fan worm. It is a segmented bristleworm with a fan of feathery tentacles on its head. It builds a tube that it lives in.This particular kind of fan worm is common on Changi, but I seldom see it elsewhere. You can see the segmented body of this worm, with tiny little bristles on segments. It has a delicate fan of feather tentacles which are banded blue and orange with tiny spots.

For unknown reasons, this kind of fan worm is often seen at low tide with its fan held in four 'petals' so it is often mistaken for a flower.I have no idea why the worm behave in this manner. Other kinds of fan worms don't do this.

Special finds this morning include the Miliaris cowrie (Cypraea miliaris). Can you see it?I don't blame you if you can't. This snail covers its shell with a part of its body (called the mantle) which has lots of projections. It looks more like a slug when it does this. I didn't find it and it was Super Slug Seeker Chay Hoon who found it.

With the mantle retracted, the beautiful shell is seen.This pretty cowrie is listed among the threatened animals of Singapore, mainly due to habitat loss and over-collection. I haven't seen it for some time. So it was a relief to see several of them this morning.

Changi of course is just splendid for sea stars. And there were lots and lots and LOTS out this morning! Of various species and sizes. Aren't they beautiful?!More about telling these kinds of sea stars apart.

Sea stars encountered today included the Cake sea star (Anthenea aspera), Biscuit sea star (Goniodiscaster scaber), Gymnanthenea laevis and of course the Sand star (Astropecten sp.), Nepanthia sp. and the Rock star (Asterina sp.).

And today, we also saw the Transparent sea cucumber (Paracaudina australis)! It's been a long time since I've seen one.The sea cucumber is smooth and indeed so transparent that you can see its internal body parts!It has tiny stubby smooth feeding tentacles.

Other sea cucumbers seen include lots of ball sea cucumbers (Phyllophorus sp.), smooth sea cucumbers, thorny sea cucumbers (Colochirus quadrangularis), some warty sea cucumbers (Cercodemas anceps), and stuck on hard surfaces the unidentified orange sea cucumbers.

Of course a seahorse should always be a special find.But we are seeing them so often these days that we are not appreciating them enough I fear.

Here's some stuff I've never seen before.

I've often seen the shell of this snail, usually with a hermit crab inside. But I've never seen one alive yet.This one was very much alive and doing something, we don't really know what. It might have been eating something or laying eggs. We waited until it stopped before having a closer look at it.Here's what it looks like from the under and upper side. I don't know what kind of snail this is.

And here's a really odd sight. Out of water and lying limp, these seem to be some kind of anemone or anemone-like animal.Here's a closer look at the strange tentacles with ball-shaped tips.The tentacles surround a conical mouth-like structure. I have absolutely no idea what it is!

And just before the tide turned, I spied a strange anemone I've not seen before.It had a body column that was 'hairy' and its tentacles were short.

Even more remarkably, as I tried to take a photo of it, it started to MOVE! It was only then that I realised that the anemone was attached to a shell occupied by a hermit crab.
But the hermit crabs was so TINY compared to the gigantic sea anemone!!Here's a closer look at the sea anemone and the hermit crab.

The sea anemone probably protects the hermit crab from predators like the octopus. If so, this hermit crab is truly extremely kiasi to have such an outsized anemone.

Alas, this marvellous shore is somewhat impacted by careless shore users.There was this patch of assorted 'rubbish' including litter and half dead animals. Possibly dumped by a collector who changed his mind. The shore was also pock-marked by holes dug up probably by fishermen looking for worms.

More about the encounters on this trip on these blogs

4 comments:

Anonymous said...

Just to share... I also saw the fan worm at changi a few weeks ago during low tide.. like you said, I thought it was some lower so I dusturbed it with my pointer and it hid away very quickly.. I waited for sometime for it to emerge again and while it was, I noticed that this critter was sort of changing colors until somehow, when the water came in, it became like the colour in your picture.. don't know how to explain.. I took a video of it too! Amazing. LOve Changi!

Cheers,
Mich

Bernadette said...

It's really so AMAZING that there are so many interesting finds on Changi, even after all these years, and even after the many "challenges" it faces like poachers, sedimentation, etc. It's always been my favourite shore to explore!!

Anonymous said...

Snail is a frog shell: Family Bursidae, should be quite frequent in deeper waters. You can find its name in Science Centre's 'Common Seashells of Singapore'

Jol said...

What is kiasi? Is krab crab? Thanks.