Friday, December 28, 2007

Sea Stars & Other Echinoderms @ Changi

Went to Changi for some filming session yesterday, and must say that despite the no-so-low tide, we had some really wonderful finds, especially the sea stars and other echinoderms! And due to the tight timing for the filming, I think we hardly even explore more than 50m of the entire shore! I'm sure we would have found even more things if we got to explore a bigger area!

Found the above orange sea star among some seaweeds. It was really small, only about 3cm wide, and thus I really had a hard time trying to ID it, as it could be a juvenile with some of the distinguishing features not very clearly developed yet. After looking at the macro shots I have of both the top and under sides, I think it could be a juvenile cake sea star (Anthenea aspera), as I could roughly make out some bivalved pedicellariae on the under side. But then, it's so tiny, and thus I really can't say for sure.

For one thing, most of the IDs we have are based on species already found locally and published in books, so there are times when I wonder if we could be looking at a new species but tried to fit them into one of the known species.

JL found this little green sea star, which is about the same size as the orange star. I took some quick photos in a hurry, and forgot to take some close-ups for ID. So pai seh... But it was really hectic yesterday, as we only have about 1.5 hours of low tide to find thing and at the same time, had to do the filming.

The above is most probably a biscuit sea star (Goniodiscaster scabra).

This one is also probably a biscuit sea star, but some tiny spokes on the top surface makes me a little doubtful if it could be a Gymnanthenea laevis. Again, was rushing for time and thus couldn't take proper ID shots.

Actually, saw several small similarly-looking sea stars while we were doing the filming, but just couldn't spare time to take a closer look for the ID. Quite a pity actually.

There were lots of sand stars (Astropecten sp.), and some of them just suddenly appeared from the sand right next to me!

And here's a special find of the day - a 6-armed sea star (Luidia penangensis)! The only other time I've seen this was at Beting Bronok. And at that time, I din take any photos because it was also left with 2 or 3 complete arms, which I really regretted! So this time round, even though its also in a rather sorry state, I decided to take more photos of it.

Here's the under side. Like the 8-armed Luidia maculata, this sea star also has pointed tube feet which allow it to burrow quickly into the sand.

There were lots of brittle stars too.

In the 50m stretch of beach we explored, I only found one black sea urchin (Temnopleurus sp.).

But I was pleasantly surprised when JL showed me this - a heart urchin! This was the first time I saw a live heart urchin. Understand that they burrow under the sand most of the time, and thus it's quite uncommon to see them. We were really lucky, I must say!

And of course, at Changi we can always find a few types of sea cucumber. Have seem the above several times, but still not really sure what sea cucumber it is. Read some where that technically, all sea cucumbers can be eaten provided that they are treated properly to remove the toxin. But I guess luckily, many of the cute sea cucumbers on our shores are probably too small to be commercially viable.

Talking about small sea cucumbers, we found many of these pink thorny sea cucumbers (Colochirus quadrangularis) among the seaweed and seagrasses.

We also found several sand dollars, which I didn't take any pictures.

Here something that are not echinoderms though. This is the first some I saw so many of them exposed on the sand surface, and I felt I just have to blog about them.

They are the button shells (Umbonium vestiarum).

There must be like thousands and thousands of them, covering an area about 1m wide and 6 to 7m long, if not more! It was just amazing to see so many of them together.

Anyway, we managed to finish the main filming as the tide was rising.

All in all, it was a good trip with many interesting finds!

Monday, December 24, 2007

Sponge & Sea Fan Garden on Ubin

While KS and company were out on Chek Jawa monitoring its recovery, and at the same time, sighting huge orange cake sea star and pink knobbly sea stars, a trio of Semakau guides (LK, ST & I) on out on an unexplored part of Ubin, or at least, unexplored by anyone we know.

So what made me decide to make this trip? Last Saturday, I took a quick at the area when the tide wasn't that low, and saw a lovely stretch of spoon seagrass with many sponges. Seagrasses and sponges are food for many marine animals, and when you can find the food, you can usually find the food-eater too.

And indeed, the area didn't disappoint me.

Colourful sponges were every where! In the little area above, there were at least 6 different types of sponges. Can you find them? Sponges are simple animals with lots of tiny holes and a few bigger holes on it. They feed by sucking water through the little holes and filter any edible particles from the water. The filtered water will then be pushed out of the bigger holes.

And there were many bigger-than-your-face carpet anemones too! Can you see the opening it the middle? That's its mouth. the anemone has sticky tentacles which it uses to trap animals that got too close to it. The tentacles eject little toxic stings into the unlucky prey, and then slowly move it to the mouth in the middle.

Swimming anemones appeared to be in season, as we saw many of them among the spoon seagrass. As the name implies. this anemone can swim by pulsating itself!

And on the rocks, there very many cute little snails, including the little cowrie above.

Unfortunately, the only sea star we found was this sand star with only 2 complete arms. It was still alive though, and hopefully it can regenerate its arms before it ends up in some other animal's stomach.

There were plenty of brittle stars though. They are so named because their arms break easily, and this helps to distract predators which caught hold of the broken arm.

We also saw several of the usual sea cucumbers found on our northern shores, including this pretty Cucumarid sp. If you imagine the colour to be green and yellow instead of orange and black, it will certainly look like a cucumber!

The pink thorny sea cucumber is also quite common on our northern shores. And by the way, do you know that sea cucumbers breathe through their back ends?

Found this ball sea cucumber which has buried most of itself under the muddy substrate. All 3 sea cucumbers above feed on tiny plant or animal matter, which they collect with their tentacles from their surrounding.

There were lots of leaf porter crabs among the seagrasses. I totally lost count of how many I saw. These crabs usually carry a leaf or a piece of wood to camouflage themselves from predators.

There were several other crabs among the seagrasses, including this master of camouflaging - an elbow crab., which blended in nicely with the surrounding mud.

Personally, I think the cutest crab we saw today must be the sponge crab. There were many of them too. Don't think I've ever seen so many sponge crabs at one place before! Strangely, I found several of them holding onto the tube of the peacock anemones. Is it trying to get some left over food from the peacock anemone? Anyway, sponge crabs are masters of camouflaging too! They usually carry a sponge or colonial ascidian which they trimmed it such that they could fit in nicely. As long as they don't move, it's hard to tell that there's a crab hiding underneath.

There were a few mantis shrimps out in the open too. They got their name from their two front claw, which resembles the front claws of a praying mantis.

And finally, we found our first nudibranch for the day, an Atagema spongiosa! Eventually found 3 of them by the end of our trip. A nudibranch is a type of sea slug - a snail without a shell.

As we walked towards the rocky side, more things were discovered, including the pretty flowery soft coral above.

And here's a sea whip, a sea fan, and a hard coral. All 3 are colonial animals, and the are lots of little holes on them to house the little coral animals called polyps. And unfortunately, here's also where my camera battery died. Sigh... forgot to charge my batteries again.

Luckily, LK and ST's cameras were still working fine without any battery or other problems. The rest of the photos below were contributed by LK.

Here's another lovely red sea fan.

In fact, at certain parts of the shore, I felt like I've entered a sea fan garden! There were so many of them!

Along the way, we found 2 other types of nudibranchs. The above is probably a Dendrodoris fumata.

And this one, a Hypselodoris infucata.

On the whole, it has really been a wonderful trip. If only the authorities can make the whole of Pulau Ubin a protected area! Sure hope all these beautiful nature things can be better preserved for our future generations!

Sunday, December 23, 2007

Chek Jawa with the Semakau Guides

Wasn't planning to blog about this trip actually as several others in the gang had already blogged. However, after going through my photos, realised that I had captured a few things that the others didn't, so decided to just give a quick account here :)

As we walk go onto the mangrove boardwalk, we saw a flowering rattan vine near the Jejawi tower. Rattan is actually a palm. So mind you, not all palms are like your coconut palm that grow tall and straight.

And on a nearby plant, we saw a pretty little jumping spider. And as per previous experiences, it jumped onto my camera while I was trying to get a nice macro shot of it.

Once again, we saw the fiddler crab which we have managed to get the ID. Male fiddler crabs have an enlarged claw that they used to attract females or to intimidate other males.

Wonder if this is the female fiddler crab?

There were lots of mangrove flatworms in the pools of brackish water in the mangroves too.

This is probably a juvenile cake sea star. Had quite a bit of discussion over what it should be actually, and in an earlier posting I had suggested that a similar-looking one could be a Gymnanthenea laevis as this sea star can usually be identified by spine-like tubercles on the central radial plates, and like the cake sea star, its bottom surface is covered with bivalved pedicellariae. However, recently I saw some spine-like tubercles on an adult cake sea star in a photo too. Since the Gymnanthenea laevis supposedly has thinner arms, I think this is most probably a juvenile cake sea star. Pai seh, should have taken a super close-up to check on some other distinguishing features on its top surface.

And here's a lovely purple carpet anemone.

Saw an Armina babai yesterday as well, but when I went home to check my photos, realised that I only took photos of its underside. Fortunately, we saw a few again today, and so managed to grab a proper photo. Anyway, this is a nudibranch that feeds on sea pen.

In the coral rubble, I saw lots of egg ribbons. Do they slug eggs? Sure looks like it.

There were lots of colourful sponges in the coral rubble too!

One animal that really intrigues me is this snail here. Found several of them in a tidal pool, but it was only when I reached home to check out the photos on my laptop, then I realised that they seemed to have some tentacle-like things at their front end. So are they snails or could they be something else? They definitely have a foot though, and wasn't swimming but sliding over the sand. Any experts out there can help answer my question?

Anyway, it was yet another great trip with fellow guides. Thanks to LK for organising this!

Saturday, December 22, 2007

Chek Jawa Intertidal Walk on 22 Dec 2007

Just a quick account of some of the things we saw today :)

We had a lot of luck with mudskippers today. Not sure what species the one above is actually, but we saw a few giant mudskippers right under the boardwalk today, though I didn't really managed to get a good shot of them. Most of the time giant mudskippers will splash their way away from the boardwalk when people walk pass, but not sure why this time round they seemed to be less shy :P

Not sure if this is a dead coastal horseshoe or its moult. It was lying on the sand just next to the boardwalk.

On the sandy shore, the resident carpet anemone was still there. Can only hope that the rainfall situation will not get worse and it will still be here the next time I came by.

Some how today was the day for sea cucumbers! We saw many of them coming out of the sand, including several ball sea cucumbers...

...and a number of this sea cucumber with black spots. Have seen this several times at Chek Jawa, but still wasn't too sure of the species. Didn't see the smooth and slimy one with brown spots that I saw during my previous trip though. Wonder if they could be the same species but different colour variation. The latter was much more slimy though.

We saw several brittlestars with broken arms and even broken central disc. This was one of the few which looks complete.

As it got darker, the sand stars started appearing too!

It rained earlier, and as we looked ahead, someone shouted that there's a pretty rainbow. This was the first time I saw a rainbow at Chek Jawa!

If you look to the right side of the photo above, you may also notice two birds on the sandflat, and another bird flying above.

Apparently, a brahminy kite or a white-bellied sea eagle (looked more like the latter, but can't say for sure since it's too far) was trying to snatch the fish caught by a great-billed heron! I think it wasn't successful though.

Some of my participants shouted to me and I walked back to them. They have spotted a mantis shrimp! Mantis shrimps have 2 front appendages which look like those of a praying mantis.

And they were also very excited to spot a few gong-gongs on the sandy shore.

As we were walking back to the floating pontoon, we also found this moon snail sliding across the sand.

On the whole, despite the rain, we saw many interesting things today. Hopefully tomorrow will be even better! :)