Sunday, February 25, 2007

Hit & Run at Chek Jawa

A fish hit me!

Was pretty sure I wasn’t bitten or stung now that I think back, it just felt like something hit me.

Yesterday, I was back at Chek Jawa with Dr Dan, his colleague and students from Duke University, and Team Seagrass. The photo below was taken after I’ve given our visitors from Duke University a short introduction to the Rhizophora mangrove tree behind, probably a Bakau Minyak (Rhizophora apiculata) since it had red stipules.

Dr Dan

As we were crossing a lagoon among the sandflats, I suddenly felt something heavy hit me some where just above my right ankle.

"What the fish!" I exclaimed.

But the water was a little murky with so many of us crossing the lagoon, and the fish was too fast for us to identify it. We could only vaguely see a longish shape disappearing with the waves.

Lifting up my leg, I saw that the fish had taken some of my skin with it.

Like what Alvin said, it’s a case of "hit and run" – I didn’t even know what hit me, species, genus, whatever.

But despite this little incident, and the fact that many of the wild things that we used to see at Chek Jawa were gone due to the flood, we still had a very enjoyable trip.

It was a bright and sunny day at Pulau Ubin - a lovely day to get away from the concrete forest on mainland Singapore. The construction of the boardwalk was proceeding well, and we had to play a bit of hide-and-seek to get to the shore.

We saw quite a number of interesting wild things, including lots of fiddler crabs, hermit crabs, swimming crabs, sand dollars, clams, snails, fishes etc. This mudskipper was found hiding among some rocks.


It’s not as big as a giant mudskipper, but it’s probably the biggest mudskipper I’ve seen so far on Chek Jawa, about 15-17cm long, and it has little blue spots on its body. Looks like a blue-spotted mudskipper (Boleophthalmus boddarti) which feeds on algae and detritus. This is the first time I’m seeing this though, so not quite sure if I’ve gotten the ID correct.

We saw many drills (Thais sp.) and lots of egg capsules as well.

Drills with eggs, Thais sp.

Drills normally feed on barnacles and other shells by secreting an acid to soften the victim’s shell before boring a hole through it with its radula (something like a tongue). Their egg capsules turn purple when the eggs hatch.


Several huge jellyfishes were stranded on the sand bar. The one above was still alive when we found it. Jellyfishes are Cnidarians like corals and sea anemones which have stinging cells. Don't handle them with your bare hands, or you may get nasty stings!

Mantis shrimp, Order Stomatopoda

The mantis shrimp (Order Stomatopoda) above was found scurrying among the seagrasses. Mantis shrimps have pincers with sharp spines to impale their preys, such as small fishes.

We were all very happy to find three living sea cucumbers, and among them a ball sea cucumber! Just imagine a month ago, we had dead ball sea cucumbers every where! Seeing a living one is surely a good indication that they are coming back!

Sea cucumber, Paracaudina australis

The translucent sea cucumber above is probably a Paracaudina australis. It's supposed to have 5 pairs of longitudinal internal muscles. You can see one of the pairs in the photo.


We had thought that this was a sea cucumber or a peanut worm. But Ria later found out it is probably a spoonworm. This was the first time I saw it actually. Read more about it at the Team Seagrass blog.

Sea pen, Order Pennatulacea, with Porcelain crabs, Porcellanella sp.

And not only we found several sea pens (Order Pennatulacea), the one above actually had two sea pen porcelain crabs (Porcellanella sp.) among the polyps! Can you spot them? A sea pen is actually a colony of animals, with a primary polyp (one animal) as the central stalk, and secondary polyps (other animals) making up the feathery end.

But the highlights of the day were these…

Hairy sea hare, Bursatella leachii

The hairy balls you see above are no balls, but are in fact slugs called hairy sea hares (Bursatella leachii)! There were like hundreds or maybe even thousands of them! From what I understand, hairy sea hares normally feed on cyanobacteria. Could this be an indication that the water has lots of nutrients, possibly due to the recent flooding, and resulted in a cyanobacteria bloom?

On our way back to the vans, we saw a cute little crab spider, waiting for butterflies to stop by for lunch.

Crab spider

Indeed, today I’ve again seen a few new things that I’ve not seen before. That just shows our wild shores still have a lot to offer! So those of you out there who have not visited our wild shares, what are you waiting for? Sign up for the guided walks organised by the various volunteer group now! More information can be found at the WildSingapore Website :)

And thanks to the staff and students from Duke University for making this trip so enjoyable. I've learnt many things from all of you, and do look forward to seeing old and new faces again next year!

Thursday, February 22, 2007

Kusu Island on CNY Day 3

The last time I went to Kusu Island was almost a year ago. We were with Dr Dan and his students then, and I saw quite a number of interesting things, including a nemo, i.e. a false clownfish (Amphiprion ocellaris) in a pool surrounded by lots of sponges and corals. Dr Dan wasn't with me then, and it was only later when I got to know they didn't managed to find any nemo that day :P

This time round, it's just the wildfilms crew and beachfleas. Zhiyuan and Weili decided to join me as well. We met up for a quick dinner before joining the others at Marina South Pier and took the boat to Kusu.

At Kusu, as we were heading towards the loo to do "you know what" before going into the lagoon, I heard someone yelling behind me.

"Don't go so fast! We want to follow you!"

Follow me to the loo???!!!????

She was one of the beachfleas who had also went with us to Sisters island the day before. But it's still quite bright now. And why did she want to follow a bunch of guys to go to the loo???!!!???

It then dawn on me that she thought that we were going into the lagoon, and she wanted to follow!!!


I yelled back at her that we were going to the loo, and everyone who heard us burst into laughter :D

Anyway, after the toilet break, we headed towards the lagoon. The first animal we saw at the sandy shore was this - a common seastar (Archaster typicus).

Sand-sifting sea star, Archaster typicus

It was busy crawling over the sand, probably feeding on the organic particles (or detritus) on the surface.

I was really hoping to see nemos, but the water was a little murky and I had a bit of problem even to find the anemones. After searching high and low, and sinking to my knee at one point into the sand, I couldn't find any nemos despite finding quite a number of carpet anemones and magnificient anemones.

As the sky turned darker, we found a ghost crab (Ocypode sp.) on a patch of spoon seagrass (Halophila ovalis).

Ghost crab, Ocypode ceratophthalmus

It was cream-coloured instead of the usual grey ones I've seen though, so not sure if this was a different species or just a colour variation. Ghost crabs are fast runners, and can move about 100 bodylengths per second, and they have excellent eyesight so as to see where they going. Otherwise, we will probably get a lot of dead ghost crabs on our shores, died from crashing into rocks or other hardy things :P

Most of the beachfleas were gathering around me then, some a little disappointed as we couldn't find the nemo. Hoping to show them more things, I decided to bring the gang to the reef near the jetty.

There were lots of zoanthids on the shore leading to the jetty, I really hoped we had not stepped on too many of them. On a rock near the jetty, we saw this beautiful Sally-light-foot crab (Grapsus albolineatus).

Sally-light-foot crab, Grapsus albolineatus

It is a scavenger, but also eats algae. And on another rock, we saw its close relative from the same family Grapsidae, a purple climber crab (Metopograpsus sp.)

Purple climber crab, Metopograpsus sp.

Not to be confused with the tree-climbing or vinegar crabs (Episesarma spp. from the same family) found in mangroves and are primarily leaf-eaters (am clarifying this as I understand some beachfleas were confused), purple climber crabs mostly feed on algae, but they also scavenge and attack other small animals. I've seen them feeding on little fishes and sea slaters, though I'm not really sure if those were hunted or scavenged. They are quite common on our rocky shores, and can also be spotted in mangroves running over the roots and tree trunks.

As we walked along the rocky shore, I found a spiny oyster (Spondylus sp.) under a rock.

Spiny oyster, Spondylus sp.

Unlike true oysters which cement to hard surfaces with their left valves, spiny oysters glued with their right valves.

As we walked towards the beacon, I spotted some reddish-orange thing smashing against the rocks with the waves. Picking it up, it was a loose sea fan (Order Gorgonacea)!!! Probably broken from its base by the dashing waves or something.

Sea fan, Order Gorgonacea

A sea fan is a colony of tiny animals (aka polyps) linked to each other, supported by a central rod made of a strong but flexible protein called gorgonin, which is similar to the material produced in the animal horns.

The water level was a little high when we reached the beacon and tide was rising. It was getting late and we decided to make our way back.

While this time round we couldn't find the nemo, it was nevertheless an interesting trip with a few good finds! :)

Wednesday, February 21, 2007

Sisters with Dan & Gang

Seems like I'm the slowest to put up my blog entry... again. Sometimes I really wonder how did the others put up their entires so quickly. Or was it because I'm ultra slow, since I'm always so long-winded with my blog entries? :P

After reading the other blogs, was considering if I should post an entry actually, since most of the things are already covered by Ria and Siyang. However, eventually decided to do it since this was really a very interesting trip, and also... for my blog's fans. (WAHAHAHHAHAAAAaa... Just kidding, like I have any fans in the first place. WAHAHAHHAHAAAAaa......)

Anyway, just to clarify things in case anyone is not familiar with Singapore's geography, the "sisters" in this entry's title refers to Sisters Island, NOT female Homo sapien siblings.

"Dan & gang" refers to Dr Dan Rittschof from Duke University and his students from US. I had the honour of guiding them at Sisters Island last Tuesday.

Dr Dan Rittschof from Duke Univeresity and his students

This was probably one of the most challenging guided walk I have led (the most challenging one being my first Semakau walk, when I was asked to guide without going through any on-the-job training). Seems like I'm saying this a lot these days, but I did not study biology in school last time. And now, I have to guide a marine biologist with his students???!!!???? Hopefully I didn't do too badly :P

It was raining when we reached Big Sisters, but that didn't stop us from venturing into the big lagoon. The first animal we found were a pair of orange striped hermit crab (Clibanarius sp.), which Dr Dan shared some really interested stories about them and their relatives, the swimming crabs. We then walked along the sandy shore on the edge of the water, and saw several other interesting animals, including flower crabs, moon snails, moon crabs, and a spider conch. As we proceeded into the lagoon, we had our first star find of the day - a diadema sea urchin!

Diadema sea urchin

While I know, and have seen, diadema sea urchins in our waters, I had never seen one on Sisters Island before! And some more, in the lagoon! That just shows how unexplored our islands are! Even though we have visited many of our islands many times, we are still seeing new things every now and then!

More things started appearing when the rain stopped. We found at least five species of flatworms, a polka-dot nudibranch (Jorunna funebris), a few phylid nudibranchs (Phyllidia nigra & Phyllidia pustulosa)a giant top shell (Trochus niloticus), several leaf slugs (Elysia ornata), several black sea cucumbers (Holothuria leucospilota) and a few octopuses. And of course, anemones, zoanthids, corallimorphs, and corals, both hard and soft, were every where.

Ria alerted us that James found a blue-spotted fantail ray (Taeniura lymma)trapped in a pool, which got many of the students excited.

blue-spotted fantail ray, Taeniura lymma

We decided to take a break while waiting for nightfall, promising more exciting finds as we know more animals come out at night when it's cooler. And after having some 100 plus, cookies and curry puffs, we're back into business again!


And the first animal which greeted our re-entrance was this huge octopus.

Mushroom coral, Fungia sp.

And as per what Dr Dan told us earlier, the mushroom corals (Fungia sp.)were much more active and beautiful at night.


Dr Dan and his students were very interested in fishes, and thus we also found many fishes, including the flathead above.

But no night walks are complete without stars, and we managed to dig out a brittlestar (Class Ophiuroidea) under some dead coral pieces.

Brittle star, Class Ophiuroidea

And yet another exciting find of the day, an eel (or at least it looked like one) feeding on an octopus!

Snake eel

And this was the first time we saw this eel! And in fact, we saw several of them that night!

And yet another exciting find, a pufferfish!


I've seen similar pufferfish with yellow fins when I was canoeing in our northen waters a long time ago, and have also seen a dead one at East Coast when I was rollerblading, probably caught by one of the anglers. Not sure if they were of the same species though, since I never took any photos.

Our walk finally ended as the tide turned. And on our way back, land hermit crabs! This one sitting in a coconut husk.

Land hermit crab, Coenobita rugosus

This was truly a very exciting day, and I have learnt a lot of things from Dr Dan. Looking forward to our next trip to Chek Jawa, and hopefully, I will learn even more things from Dr Dan and his students! :)

Saturday, February 17, 2007

Back to Chek Jawa

It’s been about a month since we had the massive dying at Chek Jawa, and I had been thinking about going back to see if things have improved. So when I checked the CJ calendar last week and learnt that we were having a walk yesterday, I immediately applied for leave and drop Adelle an email to let her know that I was available to guide.

When I reached Ubin, saw Ah Hock near the visitor centre, and he greeted me, shouting something like we have a lot of guides today. And indeed, when I reached the volunteers’ hub, there were 6 of us today! And there was only one group of visitor!!!

This means that most of us could do hunting and seeking! I was quite excited about being able to walk around on our own to check if things have improved. Was really worried if some of the animals could go extinct after this catastrophe.

Chay Hoon immediately challenged me that I won’t be able to resist the urge to guide, which I confidently told her that this time round, I would be able to resist it… Or… can I?

When we reached CJ, it appeared that much of the new board walk was already completed, thus blocking our usual route. We had to do a bit of bending and squeezing to get to the sandflats.

Some how, it seemed like the arthropods weren’t much affected by the fresh water.

The fiddler crabs were still running around everywhere around the mangrove trees.

We saw a number of swimming crabs, many unidentified little crabs and a quite few hermit crabs.

But the sea grass lagoon gave us a shock.

Looking at the picture above, one may ask, “What sea grass lagoon? That’s obviously a sandflat!”

But those of us who had visited CJ before will know that this used to be a sea grass lagoon, with lots of carpet anemones and swimming crabs. Previously, we will never associate the below statement with a carpet anemone.

Carpet anemone

They were like landmines in the sea grass lagoon, here there everywhere! But yesterday, we actually had to mark it with a stick. But still, while it looked a bit off colour, it seemed like it was coping alright with the situation now. Walking around the sea grass lagoon and the coral rubble, we found several other carpet anemones. Seems like things were certainly improving, and I hope they would recover soon, and maybe in a few months time, I would have to tread carefully to avoid the “landmines” in the sea grass lagoon again.

We did not manage to find any common sea stars and sea cucumbers, but it seemed their fellow echinoderm cousin, the sand dollars, were coping very well with the situation, and I found a number of them.

Sand dollars

We also saw lots of little longish translucent jelly-like tthings which looked like some egg capsules.

Perhaps this is another sign of recovery at CJ?

We also managed to find several fishes, including a number of juvenile catfish, a diamond wrasse and a pipefish.

Was hoping to find a knobbly seastar actually, but couldn’t find one even though I went quite far out. I saw a dead one last month, and was really hoping to find a live one – at least I’ll know that they were not wiped out. Marine biologist had not been seeing juvenile knobbly seastars in our waters these days, which may mean that there was little success in reproduction among the local population. Thus, I was really worried that the fresh water might have killed most of the knobbly seastars around our northen islands, and with the low reproduction rate, the population may eventually be extinct. Really really hope that I’m really just worrying too much here, and there is still a healthy population of knobbly seastars in our northen waters.

Adelle commented that we would be lucky enough if we could even find a rock star. I decided to start look under the rocks, and surprisingly, on the second rock I turned over, there it was!

Rock star, Asterina coronata

What a stroke of luck! It would be such a shame if the visitors were to leave without seeing a seastar!

And apparently, Chay Hoon was right after when she said I won’t be able to resist the urge to guide :P

After finding the rock star, I guess I just got so excited that I forgot what I’ve told the others earlier, and started sharing what I know about the rock star with some of the visitors (where some other visitors were running around as half of them are small kids and both parents and guides had some trouble trying to control them).

In any case, we could see some signs of recovery at CJ. It will probably take years for most of the things to come back. In the meantime, I hope that we will not experience another record-breaking monsoon in the next few years.

Read also: Chay Hoon's account of the walk at her colourful clouds blog!

Tuesday, February 13, 2007

A Book Worth Waiting For...

My hands were trembling when I received the book from Ria last week. And that's not because the book was thick and heavy.

FINALLY, I got my hands on Dr Chua's new book, "Singapore's Splendour - Life on the Edge".

For the past one year, I had been waiting and waiting and waiting and... ok, you got the drift...

So you can imagine I could hardly contain the excitement bursting inside me as I got the book from Ria. If you are reading this, thanks Dr Chua for the book, and thanks Ria for providing the delivery service :P

Simply couldn't wait till I got home, I eagerly flipped through the pages.

Immediately, a splash of colours greeted me.

Anemones, sponges, nudibranchs, crabs, shells, hard corals, soft corals, fishes, seagrasses... you name it!

Didn't want to keep Ria waiting as we had other business to discuss, I reluctantly put it down. But after the discussion on my way back home, I was there flipping and reading on the MRT again!

Memories flashed through my mind as I flipped from page to page... That's the lobster we found at St John's, the Phyllidia ocellata at Jong, the Luidia Maculata at Sekudu, the Melo melo at BB... and hey! That's me wearing that ridiculous purple cap during one of our first few Semakau walks...

No offense, Luan Keng, I love the buttons, the t-shirts... and everything else... but the purple cap??!!???!!! I can only say I'm glad we are not wearing it now :P


Yah, there's even a tiny picture of me in the book. Could hardly recognise myself if not for the purple cap (here I go again...)

But shamelessly, I will say that I'm happy to appear in such a wonderful book.

And I am also really glad that I was able contribute a tiny bit as a hunter seeker during the wildfilms trips.

While the wild things featured in this book are Singapore's splendour, the book itself is a gem among nature books!

But frankly it's not just about the beautiful photos and lovely stories... It's the love for nature, and the spirit of volunteerism.

Read the book, and you couldn't help but feel the writer's love for nature, and the spirit of volunteering for nature in the writer and those featured in the stories.

Love for nature is like the heart, while the spirit of volunteering for nature is the soul. Without the heart and soul, the volunteers will be like talking zombies. Have you encountered nature guides who rattled off scientific textbook facts, oblivious to visitors who totally "catch no ball"? Or nature photographers doing things that might endanger the lives of the wildlife they were photographing?

Not that I'm some really seasoned volunteer since I only got myself involved like one-and-a-half years ago...

But despite the fact that this is such a thick book and the language sounds a bit chim sometimes, it really goes back to the basics of appreciating and caring for the little wild things left in Singapore compared to the glorious days of our forefathers.

If only every Singaporean can find time to read this book, to experience the overflowing passion for nature, and perhaps to rethink about how we had been mistreating nature, taking it for granted...

If only every nature volunteer can find time to read this book, to recharge your "batteries", and relive the wonderful memories of time spent with nature...

Thanks, Dr Chua, for coming up with such a wonderful book.

But... What's next? Ria, I'm still waiting for your book... :P

Note: More information about Dr Chua's book can be found at his website.

Monday, February 05, 2007

Sex n the Nudi

It all began when Marcus showed me the photo of a nudibranch he took at Pulau Hantu.

Was pretty sure it's a Gymnodoris rubropapulosa as it has bigger dots and doesn't have the orange line usually found at the edge of an alba's head.

Anyway, this is how a Gymnodoris rubropapulosa looks like. Photo taken on Semakau Landfill just last month.

Gymnodoris rubropapulosa nudibranch

But before I digress too much, so what's so interesting about its sex life?

Warning: Things may get a bit R(A) below.

Can you imagine having sex at the cost of your life?

Or can you imagine having sex and also a meal (i.e. 2 in one) at the same time?

There is a Chinese saying - 饱暖思淫, which means when one has eaten and feels warm, he will think about sex. But guess this doesn't really apply to Gymnodoris.

For many of them, sex = food

Nudibranchs are hermaphrodites. Each slug has both male and female reproductive organs.

When they mate, they get into a 69 position. Sometimes they fertilise each other, at other times one may take on a male role while the other, a female.

But what's different about gymnodoris nudibranchs is that they feed on other slugs, and sometimes, that include nudibranchs of the same species.

So you can imagine when one gymnodoris saw another gymnodoris of the same species, it would mean both dinner and sex!

Bascially, they will get connected in the 69 position, and at the same time, try to move on to have a bite of the other party, and thus they will be going in circles, where the point of contact between their reproductive organs will be the centre of the circle.

It's like those old Chinese kungfu movies, where two kungfu masters walk around in circles try to find loopholes in the other party's defense and launch an attack.

Eventually, the faster one will catch hold of the other party, and starts swallowing it. Usually, the last bit of prey left exposed is the reproductive organ. Not sure if it will eventually gets eaten as well, though I do wonder if the gymnodoris's head is so flexible that it can bite onto something just next to its "waist".

And sometimes, I also wonder, if the gymnodoris is so flexible, will it actually bite onto its tail one of these days, thinking that its another prey? It's like.. "Hmmm! Yum Yum! OUCH! Shucks! I bite myself again!"

Do such things happen, I wonder? I mean, I've seen dogs chasing after their tails. Can this happen to nudibranchs as well?

But anyway, the joke of the day is when I was trying to describe things to Marcus and November, I got a bit excited and being the non-bio person, instead of saying "reproductive organs", I just said the first sexual organ term that came to my mind, "testicles".

Getting a bit crude here, but imagine, the whole slug kenna eaten except for its balls??!!??!!


In the first place, slug having balls already sounded really funny. But then again, we already have fish balls, crab balls, prawn balls, sotong balls... And mind you, sotong (aka squid) is also a mollusk like nudibranchs, maybe one day they will hv slug balls or nudi balls too???!!!???


Anyway, found out from the Net later that nudibranchs do have testes! Probably not quite like the "balls" mammals have though. Maybe something like beads or ball bearings??!!???


And the funniest of all, it din occur to me that I've said the wrong things until we had the discussion again at the prata place! And we had quite an audience sitting at the nearby tables, listening to our rather loud discussion on nudibranch sex.

Anyway, last Sunday's trip to Pulau Hantu is a good one. Haven't been there for at least half a year.

But sadly, the sedimentation in the lagoon was really getting quite bad - the water used to all the way go up to my knee, but now, only slightly higher than my ankle most of the time, even though the tide was actually not as low as the past few times we were there.

I didn't see any razor fish in the lagoon. Was thinking with the shallow water, skali they may actually kenna stuck heads down with their tails pointing skywards :P

Just kidding here, but I really hope they managed to get to some deeper pool when the tide went down.

Saw a number of the usual suspects, e.g. the Merten's carpet anemone (Stichodactyla mertensii), the Magnificent sea anemone (Heteractis magnifica), seagrasss, seaweeds, swimming crabs, stone crabs, red egg crabs etc, but din see any nemos, though I'm quite sure they were hiding in some of the anemones I saw, since I could feel quick knocks on my metal chopsticks when I was touching the anemones with them.

Some of the other wild things I saw at Hantu which I captured on photo include:

Giant clam, Tridacna crocea

One of the giant clam species. This one was not really a giant though, maybe about 10-15 cm.

Soft corals

Flowery soft corals...


Zoanthids, aka colonial anemones, look at the ones under water and you can see the opened polyps...

Galaxy hard coral, Galaxea sp.
A half-bleached galaxy hard coral... Dunno what happened to it...

Sand-sifting sea star, Archaster typicus
And on my way back, a common seastar. Not sure why, but the common seastars here seem to be smaller than the ones at Chek Jawa and Semakau Landfill. Is it because there is less food here, or are they a smaller sub-species??? Seems to have more common seastars at the other smaller lagoon though, or at least, they are easier to find. Is it because there is more food there?

Anyway, was glad to see that apart from the sedimentation, most things were still doing quite well. Hopefully the next time I go to Pulau Hantu, things will stay the same, if not better!

Read also:
1. Marcus' take on the sotong ball and his account of the trip.
2. More info on the mating behaviour of Gymnodoris nudibranchs at the Sea Slugs Forum.