Quick Look at Sisters Island on 26 Oct 2011

I was back on Big Sisters Island today for a picnic organised by a friend. As the main focus wasn't on the shore life, I only managed to sneak out to check out the shore for like an hour or so. Tide wasn't that low by then, but fortunately I still managed to find a number of stuff :)


I was most excited to find this Fluted Giant Clam (Tridacna squamosa) in the lagoon - had not been able to find it for my past few trips here! The metal stick on the right probably indicated that Mei Ling, who worked on giant clams, was studying it. This one is about 30cm wide.


Most of the people on the island were more excited about the Long-tailed Macaques (Macaca fascicularis) though. There were more than 10 of them and they were really rather daring. We were kept busy for quite a while keeping them away from the food.


The smaller lagoon, as usual, had many Sand-sifting Sea Stars (Archaster typicus). These sea stars sift among the sand for tiny decaying matter (detritus) to feed on.


There were quite a few moon snail trails. I dug one out and it was a Pear-shaped Moon Snail (Polinices mammilla).


At the mouth of the small lagoon, there were a few Haddon's Carpet Anemone (Stichodactyla haddoni), and I found some Anemone Shrimps (Periclimenes brevicarpalis) on them! These shrimps had a layer of mucus on their body to prevent the anemone from stinging them, while being protected from predators by the stinging tentacles.


I found a few tiny Ocellaris Clownfish (Amphiprion ocellaris) in some of the Giant Carpet Anemones (Stichodactyla gigantea) near the mouth of the lagoon too!


Branched Sea Anemones (Phymanthus sp.) were as abundant as ever. They looked like little flowers of the sea...


Leaf Slugs (Elysia ornata) were in season, and I saw many of them among the seaweed. These sea slugs sucked the sap of the seaweed and retained the chloroplast in their body for photosynthesis. And so they were somewhat "solar-powered", like plants!


At the rocky areas, I saw many Black Sea Cucumbers (Holothuria leucospilota) among the rocks and coral rubble.


There were many snails on the sea wall, but the limpets caught my eye, as I suddenly remembered a friend who was studying them for her honours project.


I only saw one nudibranch, a Discodoris boholiensis. "Nudibranch" means "naked gills", refering to the flower-like gills on the back of most species.


Fanworms (Sabellastarte sp.) were also rather common at the coral rubble area.


The Red Maiden's Fan (Oceanapia sagittaria) is probably my favourite sea sponge - the bulk of the sponge is actually hidden in the ground.


Sisters Island has a very nice and dense intertidal coral reef. All the brown boulders above were hard corals! They are mostly brown due to this golden-brown algae (called zooxanthellae) that live inside them. The algae photosynthesize and provide nutrients for the corals, while getting shelter in return.


Some corals, such as the Turban Coral (Turbinaria peltata) above, have their own colour pigments that act as sun block, and hence they may appear greenish, bluish or even purplish.


Coral reefs can get rather colourful sometimes - the above shows some corallimorphs among some sponges.


Algae, like the red algae above, can be brightly coloured too!


So are the colonial ascidians.


Some of the areas had lots of Zoanthids (Palythoa mutuki), which looked like little flowers carpeting the area.


Even smaller are the tiny polyps of the Toadstool Leather Coral (Sarcophyton sp.).


The tide came back rather quickly, and I had to stop my exploration. As we were leaving the island, I noticed that the trash bin were really not very monkey-proof... Hopefully Sentosa will do something about this, since they are managing the island!

Kusu Island on Children's Day 2011

Finally, I was back to explore Kusu Island! Was really glad that I managed to round up a small gang to visit this island during the pilgrimage season! I always like to visit Kusu Island during this period just to enjoy the festive mood.


Unfortunately, possibly because of the rain in the morning, there were not many that people on the island. Most of the pasar malam and food stalls were also closed. When I was here last year, it was a lot more fun with all the stalls and enthusiastic devotees shouting "huat ah!"


We only saw one Hawksbill Turtle (Eretmochelys imbricata) in the lagoon today, unlike my last trip which I saw 3 of them. Not sure where did the other two go.


As the tide got lower, we entered the sandy lagoon and the first animal that I saw was this Sand-sifting Sea Star (Archaster typicus). Also called the Common Sea Star by some, this is one of the most commonly seen sea stars in Singapore. It's often sold under the wrong name of Astropecten sp. in the aquarium trade, but more unfortunately, these sea stars feed on tiny organic particles in the sand, and hence usually cannot survive in home marine tanks.


Nearer the sea wall, several colonies of soft corals can be seen. The above is a Lobophytum sp., which has vertical outgrowths on the top surface of the colony.


There were a few Tube Anemones (Order Ceriantharia) too.


On some of the loose rocks from the sea wall, several huge patches of Corallimorphs (Order Corallimorpharia) can be seen. They are closely related to the hard corals, but do not secrete a hard skeleton like the latter.


There was a really extensive population of Branching Monitpora Corals (Montipora sp.) in the lagoon, and lots of little crabs and shrimps can be found hiding among them.


Several pretty luminous green Favid Corals (Family Faviidae) were also spotted. The bright colour comes from the coral's colour pigments, which act as sun screen to block harmful rays.


The were lots of huge Magnificent Anemones (Heteractis magnifica), many of them clustering on the same rock. These anemones can reproduce asexually by fission, and hence the various individuals found on the same rock could have originated from just one of them.


There were several Gigantic Carpet Anemones (Stichodactyla gigantea) too. And in some of the sea anemones, we saw the Ocellaris Clownfish (Amphiprion ocellaris)!


Talking about fish, the Silverside (Atherinomorus duodecimalis) was definitely one of the most abundant fishes in the lagoon.


There were quite a few halfbeaks and needlefish too. The above needle fish was quite huge, possible about 50cm long.


I saw a young Fringe-eyed Flathead (Cymbacephalus nematophthalmus), probably about 10cm long. Just see how well-camouflaged it was!


But an even better master of camouflage would be Mr Stonefish (Synanceia horrida), when you can even find encrusting ascidians, sponges and algae growing on it. Fortunately, nobody stepped onto it, as it's very venomous and the spine on its back can easily poke through shoes! And unfortunately, Syalabi who came with us got stung by something! We didn't see what stung him, but from the position on his foot, I would suspect it to be a stingray. It was a very seriously sting though, being protected by his booties, and though it was very painful initially, it got a lot better after a while. And that's why it's always very important to wear covered shoes while exploring our shores!


We also saw a Stonefish Sea Cucumber (Actinopyga lecanora), which was not venomous at all, but got it's commercial name from the fact that it's very smooth and often found stuck among rocks and coral rubble, just like another stone! Next to the sea cucumber was a Red Swimming Crab (Thalamita spinimana).


There were many Purple Climber Crabs (Metopograpsus sp.) on the sea wall, but they can be be shy and hard to photograph sometimes. I was lucky to encounter a no-so-shy one here.


Related to the purple climber was this Sally-light-foot (Grapsus albolineatus), which unfortunately had lost one of its claws! It should be able to replace it when it next moult though.


Red Egg Crabs (Atergatis integerrimus) were quite plentiful too. These brightly coloured crabs are mildly poisonous.


A few Smooth Spooner Crabs (Etisus laevimanus) were seen in the lagoon too. The tips of its claws were spoon-like to enable it to scrape algae to feed on.


As we were heading out of the lagoon, we encounter a few of these fast runners - Ghost Crabs (Ocypode ceratophthalmus).


There were also a few Land Hermit Crabs (Coenobita sp.). Didn't have time to examine one closely to confirm the species though.


One of the prettier shrimp that can be found in Singapore waters must be this brightly coloured Red Shrimp (Processa sp.)!


Yet another very pretty shrimp would be this Anemone Shrimp (Periclimenes brevicarpalis), which lives among the stinging tentacles of huge anemones for protection.


We also saw a few octopuses, which changed their colours as they moved around!


I found this Arabian Cowrie (Cypraea arabica) under a rock. It's one of the bigger cowries that can be found in Singapore.


This was another huge cowrie I found under a rock, about the size of an Arabian Cowrie. Not sure if it could be a juvenile Arabian cowrie, but the patterns on the shell were just not right.


From the underside, it did look like a juvenile cowrie as the shell still appeared incomplete.


Another cowrie highlight for me would be this Four-spotted Cowrie (Cypraea quadrimaculata), which previously I had only seen dead ones at Semakau.


We found a few flatworms, but this was the only one that I managed to take a photo - an Orsak's Flatworm (Maiazoon orsaki).


There were quite a number of feather stars near the reef edge, including these 3 Red Feather Stars (Himerometra robustipinna) on a Barrel Sponge (Xestospongia testudinaria).


And I was especially happy to see a Yellow-lipped Sea Krait (Laticauda colubrina), which I had not seen for a while! In case you are wondering why it is called a sea krait, the kraits are a group of venomous snakes from the the genus Bungarus, and they come with bold striped patterns of alternating black and light-colored areas. As Laticauda colubrina also come with striped patterns, and it lives in coastal areas, it is hence commonly called "sea krait".

It was great to be out exploring our shores with friends, and I was relieved to hear from Syalabi that he's feeling ok from his injury now. While I enjoyed guiding people on nature walks, it's always nice to be able to take my own time to explore our shores, especially these days I often conduct walks without hunter-seekers, which can be super stressful when you try to find things on your own. Haha..