Guided walk at St. John’s

Today was really a very busy and tiring day for me. I went to a NSS guided walk by Dr Shawn Lum at MacRitchie in the morning, before heading out to guide at St. John’s Island. I will blog about that former trip later since I will need more time to assimilate the information first. Guess this post also probably save my nature blog from turning into a 100% botanical blog. Ha~

Anyway, straight after the morning walk, I immediately headed back home, had my lunch and rushed out to Marina South Pier. Unfortunately, I overslept in the MRT and ended up having to take a cab from Tanjong Pagar. So much for me trying to save up after buying my DSLR and IPhone 4.

Above shows our participants listening attentively to Jun’s brief talk about this island. They are a group of  scouts from a secondary school in Clementi (Sorry for forgetting the name).

They were subsequently brought to the Tropical Marine Science Institute where ML guided them around the facilities.

Thereafter, I was ‘arrowed’ to do a last minute guide at the mangroves, of which I just quickly lead through, since the main attraction is at the intertidal shore.

During the shore walk, we split the group into two, and I was tasked to lead the guys. Here is my lovely assistant guide, Michelle, telling them more about the flower crab moult in her hand.

There were lots of acorn worms pushing hard to get the processed sand from their butt.

An definite attractive for them is this common sea star. Many Sea stars feed by pushing out their stomach and engulf its prey before bringing back in again. At least for this sea star, they are not predators but just feed on the detritus.

Our hunter seekers found this minuscule fish which I have totally no idea what it is. Apparently they also don’t but guess it just looks interesting to show. :P

Snapping shrimps are pretty common today. These animals have an enlarged pincer, and used that to fire a jet of shock wave to stun or kill their prey.

Well, its has been usual practice for me to forget taking enough photos to really give a comprehensive account for my participants to recap here. But I guess what was most important is that they enjoyed themselves, and I think they did. :)

It has been really quite a long long time since I last led a group for a nature walk (the last one was in March). A bit rusty but I think I still have some juice left in me to do a decent walk. Guess I do miss it terribly! And its always worth it to see the smiles of my participants enjoying the nature along with me.

Thanks to Jun for organising the walk~

TMSI’s first St. John guided walk

I decided to help out with Tropical Marine Science Institue’s (TMSI) first guided walk at Saint John’s Island yesterday, coordinated by Jun. More information can be found here.

It seems like the longest time since I last guided (about three to four months), and I have to do some last minute ploughing through the notes prepared by Jun. Luckily my participants were an enthusiast bunch of students from Queensway Secondary School, and I have to spend most of my time answering their questions instead of me initiating them.

Unfortunately, I did not take much photographs for the trip as I did not want to dirty my reasonably new camera. Here are some snapshots of the participants:

Three girls from R’s group.

My group peeping at the Onch Slugs at the pipeline.

All of them were jubilant taking the big Singapore Island Cruise boat back mainland rather than the noisy, rocky orange boat which we took when going to the island.

Another fun trip!

12 Jul St. John’s Intertidal Walk

I am back on another guiding trip with RMBR and this time I am leading a corporate group from Gammon Construction.

The weather had not been good for the past few days and a torrential rain was threatening to fall when we first started off to the island. Luckily, it only rained on the mainland.

I must first apologise for the lack in photos as many of them were very low quality thus unusable. It is always hard to take good ones during guiding.

We headed straight to the rocky cliff where we have a few interesting discoveries. First up was this flatworm, Pseudoceros sp.. Some species are known to practise the art of penis fencing so as to impregnate their partner without being stab and fertilise by the other and inheriting the cost of being a pregnant female.

An attractive fiery Fireband Murex (Chicoreus torrefactus) is a predatory snail that drills through shelled molluscs and suck out the flesh of the animal.

The hunter seekers managed to find a small black Sea Urchin (Diadema setosum). These spiny animals have a dorsal orange anal spot surrounding by five eye spots. They are very sensitive to light and their spines can hover and point in the direction of your hand if your shadow is over it.

Here is a Turban Shell (Turbo bruneus) with its rounded and polished lid which is used to clamp and enclose the shell’s opening tightly.

A Soldier Crab (Dotilla myctiroides) is an interesting crab that can walk forward unlike most crabs that can only walk sideways. I guess this has a lot to do with their leg anatomy; and walking sideways also allows burrowing crabs to creep in their narrow holes without getting stuck.

The find of the day is definitely this Mud Spiny Lobster (Panulirus polyphagus). It was found by my participants and I had initially thought that they were joking when they told me about it. Turned out to be a real one except that it was just the moult. This is enough to brighten my day though! Thanks to Richard for taking this candid shot of me using his DSLR.

And thus, we ended our walk by going to to TMSI for a short tour looking at Lionel’s coral nubbins and other stuff. :)

28 Jun St. John's Intertidal Walk

Another backlog dated as stated in my title.

After 4 consecutive days of intertidal walks from Tue to Fri, I was really shag... Thus decided to call off my planned trip to Tanah Merah with KS. If not my low immunity due to the lack of sleep will probably make me an excellent candidate for the flu virus. Sorry for the dropout KS.

But I am back again on Sun for a guided walk at St. John's with the public.

This is the most common star in local waters thus known as the Common Sea Star, Archaster typicus. Many stars, including this one can secrete anti-fouling chemicals to prevent harmful organisms from growing on them. Surprisingly at least for me, cholesterol is one of such chemicals. At least it have some use on the outside rather than as fatty desposits in the body.

Fiddler crabs are a common sight at low tide because it is a time for them to feed on the nutritious sand particles. A study by Dr Dan showed that their long eyestalk are actually organs that give the cue to stop feeding or else they will gorge themselves silly. And thats what happened what he removed the eyes (eww..). The crab above is a Orange Fiddler Crab (Uca vocans).

We found several burrowing Breasted Moon Snails (Polinices mammatus) in this sandy lagoon too. I guess there is no need for any explanations as to how it got it's name.

One of my participants found this weird looking Annelid worm creeping on the sand. This is my first time seeing one in green colour.

Once again, I managed to find one elusive Anemone Shrimp (Periclimenes brevicarpalis) hiding under a Carpet Anemone (Stichodactyla haddoni). These shrimps just like the clownfishes have a layer of mucus coating that prevents the stinging tentacles of the anemone from firing at them.

A rather common sight on rocky shores are the Turban Shells. This species should be Turbo bruneus with its slightly bumpy trapdoor. Apologises for these low quality pictures. Really hard to concentrate on focusing while guiding.

Here is a Land Hermit Crab (Coenobita sp.) fitting snugly inside a nerite shell.

This Flatworm, possibly Pseudobiceros uniarborensis is known to have two penises. This definitely increased the level of difficultly during their art of penis fencing!

Two portions of the rocky cliff were coated with a layer of cement, possibly to stabilise the region from the recent landslide. In fact, most of today's participants had to postponed their earlier bookings in March due to this particular incident.

I forgot to take a group photo of my group, the spider conch hence I will just show this picture of them filling of their feedback form.

Anyway, I got minus a point from one of my participants, Zenn at the category for being a knowledgeable guide as I do not know how to ID a fish. Ha, that is definitely a group that I really have to work on. Anyway, if you are reading this, I managed to find out that fish's ID. It is a Sweetlip Fish (Plectorhinchus gibbosus), named due to it's irresistable thick sexy lips. :)

First public intertidal walk at St. John's island

Today was our first public intertidal walk to St. John's island. And boy, it was really quite an opening with many first-time sightings for me. Both Henrietta and I were guiding a group from the National University of Singapore Society.

We headed to the sandy lagoon where we saw several animals feeding.


The first was this worm, probably a ribbon worm that was spotted by my participants. Can you see that it was actually entangling itself on a prawn?


The poor animal was struggling frantically. Unfortunately, the worm had a stronger grip and it eventually swallowed the prawn whole. You can actually see its mouth opening to engulf it!


The second animal which caught my attention was this snail. I know that it was a whelk from its long flexible siphon which is used as chemosensory organ. But I was confused seeing a sickle shape structure sticking out, just like the trapdoor or operculum of a conch. However, closer examination revealed that it was actually the big pincer of a male fiddler crab! SK, our molluscs expert commented that this olive whelk (Nassarius olivaceus) was probably just feeding off a dropped off pincer.


The next discovery was found by our hunter seeker, RH. The beautiful animal here is a sundial snail (Architectonica perspectiva). This uncommon snail is listed as Endangered in our Singapore's Red Data book. Thus, it was heartening to see it laying egg masses today, meaning that we might be seeing little baby sundials in the near future? You might want to see KS's blog for more information about this animal.


Another first time is this little pebble crab (Leucosia sp.). True to its name, it's exoskeleton looks just like a piece of rock allowing it to blend into its surroundings.


Here is the dear friend of Sponge Bob; Patrick the starfish. Even though the common seastar (Archaster typicus) normally comes with 5 arms, it is not uncommon to find some with less. However, when I was telling my participants that this resembled the ninja's shuriken and flipped my chopsticks to make it more descriptive; droplets of mud from my sticks flew and splattered over one of them. Oh dear, if you happen to read this post, my sincere apologises again!


We saw several land hermit crabs (Coenobita cavipes) at the rocky cliff. These crabs although found near the shore, can drown if they are submerged in the water.


Here is a pretty fireband murex snail (Chicoreus torrefactus). They feed by secreting acid to soften the shell of a molluscs and drilling a hole through it using their radula before sucking out the insides.

A fine though scorching hot day at St. John's, thanks to many of my keen eyed and enthusiastic participants.

St. John's Island Recee

About a week back (Sorry for the delay but my 5 yr laptop died before I can make this post), some of the RMBR guides went over to the opposite side of St. John's island intertidal which was facing the Sister's islands for a recee trip to see what life does the rocky shore have.


The most common echinoderm there was probably this black sea cucumber (Holothuria leucospilota), which was all over place, especially under rocks. This one was out in a tidal pool, spreading out their branching tentacles to feed on detritus.


Another common resident in this rocky area was this branching anemone, Phymanthus sp.


We also found two lovely Pseudobiceros uniarborensis flatworms. They move and swim by undulating the sides of their body as shown here.


What I initially thought was a mud crab turned out to be a spotted belly crab (Ozius guttatus) because of its polka dotted underside. Just like its cousin, it is also armed with powerful crushing pincers to feed on shelled molluscs.


RY found this small Black Spined Sea Urchin (Diadema setosum). The orange 'eye' on the centre is actually the anal hole for waste disposal!


We also found several Giant Top Shells (Trochus niloticus) hiding between the rocks. These huge snails were collected for food and when polished, their beautiful shells are used for ornamental purposes and for making buttons.


Diamond Wrasse (Halichoeres dussumieri) has a thick lip which hides a extendable jaw that can jut outwards for feeding purposes.


Here is a pretty calcareous red algae (Tricleocarpa sp.), among the many species of seaweeds that can be found in this area.


I saw this pair of intricately designed oysters, Alectryonella plicatula. According to our molluscs expert SK, this is one species that can be eaten.

St John's Island exploration

Some of the Semakau guides stayed overnight at St John's island the last weekend to try out some of their facilities for future events. December was the monsoon period and it rained heavily during the afternoon. Luckily it stopped just on time for us to visit a small patch of mangroves where the locally rare Avicennia marina was found (unfortunately my picture was too blurred).


After that, we walked along the intertidals to reach the rocky shores. Along the way, we sawan army of crabs scurrying along the mud. This is the first time I saw the soldier crabs, Dotilla myctiroides moving in such masses, as beach development had decline this crab's numbers that they are listed as vulnerable in our red data book.


There were lots of onch slugs on a pipe leading out to the sea.


The rocky shore is practically covered with sargassum and bryosis seaweeds. However, life can still be found here. Above is a video of a spider conch flipping itself over using its unique sickle-shaped operculum.


July with his keen-eye spotted this Phyllidiella pustulosa nudibranch.


There were also lots of blue coral (Heliopora sp.) near the reef edge


Someone spotted this magnificant juvenile blue spotted fan-tailed ray lying lazily on the sand.


Two brain corals which often confused me. Lobophyllia sp. with its deep gorges between the ridges;


and Symphillia sp.


Nearer to the night, Robert found this flowering sea poison (Barringtonia asiatica).


The next morning when we were at the jetty ready to depart the island, we saw that the high spring tide had raise so high that it was overflowing the concrete banks.