First Intertidal Walk at Pulau Hantu on 2 Apr 2010

This was the very first time we had a guided intertidal walk on Pulau Hantu, and we were really lucky that the weather was fine, despite earlier weather forecast saying that it might rain!

Located to the south of the main island of Singapore, Pulau Hantu actually comprises 2 smaller islands - Pulau Hantu Besar (Big Ghost Island) and Pulau Hantu Kechil (Little Ghost Island). Legend has it that 2 great warriors had a fierce battle at sea, and many people died. The spirit of the sea was very upset with this and intervened, and created a whirlpool that sucked in both warriors. The warriors continued fighting and eventually they killed each other. The gods felt it was wrong for the spirits of the sea to interfere in human affairs, and thus the two dead warriors were transformed into the two islands of Pulau Hantu.

The two islands are now very much reclaimed, but many marine life managed to settled here and hence there are usually lots of interesting things to see here.


There were many elbow crabs (Family Parthenopidae) in the sandy lagoon. They are very well-camouflaged as they trap sediment on their body, allowing them to blend really nicely into the surrounding. They got their name from the shape of their pincers, and the way they usually place them.


We saw a few spider conches (Lambis lambis) too, and a number of dead ones too. This snail has 2 eyes on stalks, allowing it to peep out of its shell to look out for dangers before it starts moving around. It also has a long, sickle-shaped trapdoor, which allows it to hop around like a pole-vaulter.


There were several giant carpet anemone (Stichodactyla gigantea) too. These sea anemones have sticky tentacles which sting small animals that have gotten to close to them. The tentacles will then transport the prey, acting like a conveyor belt system, to bring it to the centre of the animals where the mouth is located.


We saw a few octopuses (Order Octopoda) too! The octopus is said to be one of the smartest invertebrates, and are known to be able to solve puzzles and learn by observation! It is also able to spray a black ink to confuse predators, and change its colours to blend into the surrounding!


The stars of the day must the many red feather stars (Order Comatulida)! We can usually find a few of them on a trip to Pulau Hantu, but I saw like almost 10 of them on this trip! The participants were all quite excited to see these pretty animals, as we don't usually see them on other intertidal walks. Feather stars got their name from the the fact that they appear like balls of feathers, due to their feather-like tentacles. The feather star uses these tentacles to trap plankton and tiny organic matter in the water column for consumption. The mouth is located at the middle of the animal.


There were quite a few magnificent anemones (Heteractis magnifica) too! This is the sea anemone that is featured in the movie "Finding Nemo" as Nemo's home. Unfortunately, we did not find any clownfish among the anemone on this trip.


Instead, I found a stinging nettle jellyfish among the tentacles of one of the magnificent anemones. Guess this unfortunate jellyfish may end up as the food of the anemone.


The stinging nettles (Chrysaora sp.) were in season, and we saw many of them. They were seriously every where! These jellyfish can give rather painful stings, and in fact, a friend of mine unfortunately got stung by one while swimming in one of the lagoons in Sentosa recently.


While we saw a few jellyfish in Pulau Hantu's lagoon, what caught our attention was the many sand-sifting sea stars (Archaster typicus)! This is probably the most common sea star found in Singapore, and can be found on most our southern islands and a few northern shores. This sea star is often wrongly identified as an Astropecten sp., especially in the aquarium trade.


Today was really a nudibranch day, as we saw quiet a few of them! Among them was this funeral nudibranch (Jorunna funebris), which got its name from the black-and-white coloration. "Nudibranch" means "naked gills", refering to the exposed gills on the back of most species.


There was also a black margined glossodoris nudibranch (Glossodoris atromarginata). Its bright yellow and black coloration serves as warning colours to tell predators that it is poisonous. Nudibranchs are basically snails without shells, and they have lost the shell for good reasons, such in the case of this nudibranch, which is poisonous.


I also found this pustulose phyllid nudibranch (Phyllidiella pustulosa) on a rock, and it is also a very poisonous nudibranch.


One of the guides found this Gymnodoris nudibranch (Gymnodoris sp.). This nudibranch feeds on other slugs, and the one above certainly appeared to have eaten something! Being hermaphrodites with both male and female reproductive organs, many nudibranchs fertilise each other while they mate. In the case of Gymnodoris nudibranchs, they often attempt to eat up each other while mating! As such, the one which got eaten will serve as the father and also provide nutrients for the mother and its future generation, while the other will serve as the mother and lay the eggs!

Despite this being the first time we had a guided walk on Pulau Hantu, it was a really great trip with lots of interesting sightings. Thanks to all the participants for being such enthusiastic nature lovers, making this walk such a successful one!

Chek Jawa on 27 Mar 2010

Today, I was back at Chek Jawa for a guided walk. It was a very hot day, but I was really glad that it did not rain like the past few days.


With me was a really huge group, most of them from Schering Plough! And they knew one of our very own RMBR volunteer, Helen, who's also from Schering Plough. Schering Plough has a complex at Tuas, and right next to the complex was a really nice intertidal area with lots of marine life! We have been rather fortunate that Schering Plough had been giving us access to the intertidal area at Tuas.

Back to Chek Jawa, it was a really hot and sunny day, and the shore area felt rather quiet. Guess many of the animals are probably hiding from the heat. We still managed to see a number of interesting animals, though I did not managed to take many photos as this was a really big group, and guess I was too busy managing the group and forgot to take photos most of the time :P


One of the few photos I took was of this bronzeback snake (Dendrelaphis sp.). This was probably the most cooperative bronzeback I have seen so far. It was just slowly slithering around, and we could take all the photos we want! Not really sure exactly which species this was though.


At the intertidal area, we saw quite a number of marine life too, despite the heat. Here's an orange striped hermit crab (Clibanarius infraspinatus). Despite the name, hermit crabs are not true crabs. They have a rather soft abdomen, and need to hide it in a dead snail's shell for protection.


There were a sand star (Astropecten sp. on the left) and a sand-sifting sea star (Archaster typicus) too. It is interesting to note that sea stars are actually brainless. Yet, they can move around, eat, shit etc etc etc. It's just really interesting to see that some animals can be so different from us, but they can get along with their daily lives just as well! Quoting from a movie, just having a brain is really highly over-rated. You can survive well without one! In fact, studies on some temperate sea star species shown that some sea stars can live for hundreds of years! Like I always say, no brain, no worries! Haha.


There was also a little horseshoe crab. Horseshoe crabs are really ancient animals. They are often called living fossils as they existed for more than 400 million years ago, even before the dinosaurs! And one reason that they are so successful is their rather unique way of dealing with bacteria infection. When a horseshoe crab is infected with bacteria, its blood will clot around the invaders, becoming somewhat gel-like, trapping the bacteria inside to render them harmless. And it is also because of this special property that make horseshoe crab blood so important in the biomedical field. Many of the drugs we take for various illnesses are tested with horseshoe crab blood for contamination before they can be consumed. And our scientist at NUS have come up with a way to clone the compound in the blood that gives it this special property, and hence less horseshoe crabs need to be caught for blood extraction these days.

We also saw other things like sea anemones, sea cucumbers, various snails, clams etc, but I did not have photos of them.


Here another group shot just after we completed all the stations.


This was something that we saw after the walk - a scorpion! Alan found it just behind the visitor counter. This was also my first time seeing a scorpion on Ubin! Apparently, the NParks staff found another much bigger scorpion, the black one, sometime ago. Unfortunately, it was a road kill, and they have collected and preserve the dead animal. Really hope to see a live one one of these days.

Anyway, all in all, it was good to be back on Ubin. Despite the hot weather, hope that the visitors had enjoyed themselves! :)