New Year's Day on Pulau Hantu

It's New Year's day, and we were at Pulau Hantu doing our recce for our upcoming intertidal walks. Unfortunately, even before we went onto the intertidal area, it started pouring, and didn't stop until about an hour later.

Still, we were really thankful that it did stop after all, and our trip was not wasted sitting inside the shelter.


But when we reached the reef area, we were greeted by a sargassum bloom! Almost everything was covered, and we could hardly see anything! We had to move near the edge of the sargassum bloom most of the time as we won't know what we were stepping on if we were to go into middle of it!

Still, at the edge of the bloom, there were a number of things to see.


Hantu has lots of these Lobed Leather Corals (Lobophytum sp.). These are soft corals, and do not have the hard calcium carbonate skeleton that hard corals possess. There are still colonial animals though, comprising lots of coral animals (aka polyps) connected by a shared tissue. Many of these colonies are known to be able to secrete chemicals to prevent other encrusting organisms from growing over them.


I came across this huge Red Egg Crab (Atergatis integerrimus) trapped in a small tidal pool. This crab got its common name from its somewhat oval-shaped carapace. While the Red Egg Crab may look like a "cooked" crab since it is red in colour, it is certainly not something you want to have for a meal. This crab is known to be mildly venomous, and its bright colour advertises this fact to would-be predators that they are no good for eating.


The only nudibranch I found was this Bohol's Nudibranch (Discodoris boholiensis), and it certainly did not look too healthy, probably due to the rain earlier which exposed it to too much fresh water. The term "nudibranch" means "naked gills", refering to the exposed gills on the back of most species. This nudibranch has a rather interesting defence mechanism - it is able to break off part of it's wide mantle skirt when disturbed. So while the predator is distracted by the broken bit, it escapes to safety.


One of the volunteer found this Tigertail Seahorse (Hippocampus comes). This seahorse is a female, and I know because it lacks a pouch on its belly, but has a protruding structure called an ovipositor instead. This ovipositor is used for depositing eggs into the male's pouch. And indeed, male seahorses are among the best fathers in the animal world! They are the ones who will carry the eggs, fertilise them, and protect them until they are hatched! So if you see a pregnant seahorse next time, take note that it is a male seahorse, not a female.


As we were heading back to the lagoon, I came across this little red shrimp, which I had no idea of its ID.


There were several Phymanthus Anemone (Phymanthus sp.) too. While they look like flowers, sea anemones are actually animals that need to feed on other things to gain energy. To feed, they sting and capture small animals with their stinging tentacles, and move them to the mouth in the middle. The meat and soft tissues will be digested, while the hard skeleton or shells will be spitted out. So as you can see, they have no need of an anus, since everything goes in and gets out from the same opening!


We also saw a few flatworms, including this back one, possibly a Pseudoceros sp. Flatworms got they name from there very flat bodies that are seldom more than 1 mm thick! Being flat has it advantages, as it can easily squeeze into narrow cracks and crevices to escape from predator and also to seek for small or sessile animals they feed on in these places. However, being flat also means that they are very fragile and tear easily when handled, so please do not hold up a flatworm when you see one.


As we were in the lagoon, I noticed several huge colonies of Branching Hard Corals (Montipora sp.). Like the soft corals mentioned earlier, these colony comprise lots and lots of polyps living together. But unlike the soft corals, they have a hard calcium carbonate skeleton instead of a shared tissue. Most hard corals exhibit a characteristic brownish tone, as they harbour a golden brown algae inside them. Called zooxanthellae, these algae photosynthesizes and share some of the food with the coral, and in return, the hard coral provides a shelter and nutrients from its waste products for the algae.


Just before we left the lagoon, we saw lots of Sand-sifting Sea Stars (Archaster typicus)! These sea stars burrows into the sand to escape predators and to feed on the tiny decaying matter among the sand particles, hence the common name. The above photo shows two sea stars that had paired up! The one on top is the male. No internal fertilisation takes place while the sea stars are pair up in this position, and thus this behaviour is called pseudocopulation, which basically means fake sex. They may pair up for up to 2 months before they spray their eggs and sperm into the water. It is believed that chances of fertilisation is higher when they are in this position.

We saw a number of dead heart cockles too, and Peiya eventually found a living one. Unfortunately, I wasn't there when she found it, so did not have a photo. Check out Marcus's new blog for the photo :P

All too soon, it's time to go! Fortunately, despite the rain, we still managed to had a good time and finalised the route we would during the guided walk! :)

Afternote: Heard that Ivan got stung by a stonefish. Do hope that he will get well soon!

Exploring Tanah Merah on New Year's Eve

It's New Year's Eve, and I was out on my own at Tanah Merah.


I started with the rocky area, and among the first animals I saw was this Burnt Murex (Chicoreus brunneus). This murex feeds on clams by secreting an acid to soften the shell before drilling a hole through it using a tongue-like structure called a radula.


I found this Black Long-spined Sea Urchin (Diadema setosum) near the sea wall. This sea urchin has venomous spines, which break easily upon contact. It feeds on algae.


Realised that I had not taken any photos of Turban Snails (Turbo spp.) for quite a while, and so decided get a few shots. The common name was given as the shell was shaped like a turban.


There were lots of oysters and limpets stuck to the sea wall.


There were lots of Volcano Barnacles (Tetraclita sp.) stuck to the sea wall too. Barnacles are actually crustaceans, and appear like little shrimps in their juvenile stage. They eventually find a hard surface, stick their heads to it, build the wall around them, and filter tiny organic particles from the water using their hairy legs.


There were a few small sea fans too, but I did not see any allied cowries on them.


On the other hand, I found many soft corals with allied cowries (Ovulidae). The one above was found on a pink soft coral.


Here's another on a yellow soft coral.


On some soft corals, I even found 4 or 5 of them. Here's two of them.


I saw a few tube anemones too. They are so-named because they live in a tube made from mucus and sand.


There were a few Haddon's Carpet Anemone with anemone shrimps (Periclimenes brevicarpalis), The bigger female looks like it has a parasitic isopod on the left side of its head.


I saw a number of cockles (Cardiidae) today.


And here's a Spider Conch (Lambis lambis), so-named due to the long spines extending from the shell. The long curvy structure at the shell opening is the operculum, which helps to block the "doorway" from predators. In the case of conches, it is use like a "walking stick" which helps the snail to hop along as well.


There were a few Sand Dollars (Arachnoides placenta), which are the "flattened" relatives on sea urchins. Their spines are very short and tiny, which are used to help help them move around and even burrow.


There were a few Gigantic Carpet Anemones (Stichodactyla gigantea) but I did not see any clownfishes.


Several moon snails (Polinices mammilla) were spotted, burrowing just under the sand, probably searching for little clams or snails to feed on. They got their common name from the rounded shapes and white shells of many species.


There were probably thousands of Sand-sifting Sea Stars (Archaster typicus), which can burrow into the sand to escape from predators to find food. They feed on tiny decaying matter in the sand.


Another burrower will be this Sandfish Sea Cucumber (Holothuria scabra). I found 2 of them. This is the sea cucumber that is served in Chinese restaurants, but note that they must be properly processed to remove the toxins in them before they can be consumed.


Shore trips can be dangerous, and that's why we always advise members of the public to followed guided tours. Can you see an animal among the dirt and rocks above?


Brushing away the sand revealed a Stonefish (Synanceia horrida). This is one of the most venomous fish in the world! It has a venomous dorsal spine, and anyone stepping on it will get the spine poked through his/her foot, releasing venom into the wound. While they seldom cause death, the experience is still going to be extremely painful, and will probably land you in hospital for a few days. The pain may also persist for up to a few months. If there are complications such as secondary infection, it may even cause death.


Another master of camouflage is this sole fish. It is very flat and can flap its body to stir up the sediments, which will eventually settle down covering the animal.


Near the sole fish were a pair of fan worms (Sabellastarte spp. or sp.?). The feathery fan is actually tentacles growing on the head of the worm, which is used to collect plankton and tiny decaying matter in the water. Most of the time, you can only see the tentacles of the worm, as it lives in a tube made from mucus and sand.


Leaf Slugs (Elysia ornata) appear to be in season, and I saw many of them. They appear like a leaf, and hence their common name. These slugs are partially "solar-powered", somewhat like our hybrid cars on the road. They suck the sap of seaweed to feed on, and is able to retain the chloroplast (subunits in cells which can photosynthesize) in its body for photosynthesis, supplying the slug with food!


I also saw many Synaptid Sea Cucumbers (Synaptidae). Indeed this longish animal is not a worm but a sea cucumber. It has a mouth rimmed with tentacles, and it lashing these tentacles around to pick up tiny decaying matter form the surrounding.


One of my favourite animals at Tanah Merah must be this porcelain crab (Porcellanidae). Have gotten the name from Peter previously, but left it in office. This procelain crab is usually pinkish red in colour, and red is "merah" in Malay, certainly making it a nice mascot for Tanah Merah!

This porcelain crab is also much larger than the other porcelain crabs that I have seen else where. Most I have seen are less than 1cm wide, but for this one, the carapace itself is almost 2cm wide! Cheated a little here, as I did not actually managed to take any nice photos this time round as they were really fast, so this photo was from a previous trip that I did not blog about. Haha :P

In any case, this was certainly a great trip, with lots of interesting findings as usual!