Thursday, April 30, 2009

Back to Cyrene Reef

Yesterday, I was back to Cyrene Reef with a few other RMBR volunteers. It's been a while since I last visited this little reef, and thus I was really quite excited about the trip :)

Cyrene Reef
Cyrene Reef is a patch reef that is only exposed during very low tide. We set off when it was still dark, so that we could reach the exposed reef at first light.

And here's our boat! Took this photo when I was sitting in the rubber dinghy on my way to the exposed reef.

Knobbly Sea Stars (Protorester nodosus)
One of the nicest thing about Cyrene is the numerous Knobbly Sea Stars (Protorester nodosus). Interestingly, I could still remember during my first trip here, the whole gang of us walked all around the reef and we only managed to find 1 of them. But during my second trip a few months later, somehow their population went into an explosion, and we started seeing them every where!

Knobbly Sea Star (Protorester nodosus)
This Knobbly Sea Star unfortunately only had four arms left.

Knobbly Sea Star (Protorester nodosus)
I found this Knobbly Sea Star on the soft coral, and had initially thought that perhaps it was just sliding over it. But when I picked it up and looked at its underside, I noticed that its stomach was out and there were still little bits of particles stuck to it. Was the sea star feeding on the soft coral?

Knobbly Sea Star (Protorester nodosus)
Found this knobbly which somehow looked like an albino - the usual knobblies normally have darker nodules, but this one is the same colour all over.

Pentaceraster mammilatus
After a while, SY found the Pentaceraster mammilatus - a sea star which I hadn't had a good photo yet.

Sea Star
SY also found this other sea star which looked a bit weird. It has much smaller nodules and thinner arms.

On the upperside, it has web-like patterns which resembles those of the Pentaceraster mammilatus.

At the tip of its arms on the underside, there were little spines that was not typical of Protoreaster nodosus.

Is this a new species, or is it a hybrid? If it is the latter, it can really be a little worrying, as hybrids are usually infertile, i.e. they cannot reproduce! Hybrids may compete with the original species for food and other resources, but since they can't reproduce, they may end up causing the population of the original species to be reduced as the latter were out-competed!

Cushion Star (Culcita novaeguineae)
Seemed like SY has quite a bit of sea star luck, as he also spotted this Cushion Star (Culcita novaeguineae).

Sand-sifting Sea Star (Archaster typicus)
And at the sandy shore, there were lots of Sand-sifting Sea Star (Archaster typicus). The above 2 has paired up, getting ready to release their eggs and sperm into the water. Studies shown that the actual spawning may occur 2 months after the pairing.

Stonefish Sea Cucumber (Actinopyga lecanora)
Among the seagrass, I found a Stonefish Sea Cucumber (Actinopyga lecanora). On other islands, I mostly find them hiding among rocks or corals, and rarely among seagrass.

Black Synaptid Sea Cucumber
There were quite a number of Black Synaptid Sea Cucumbers too.

Flatworm (Acanthozoon sp.)
RH found this Flatworm (Acanthozoon sp.), which obviously got its common name because it's very flat! It is thus able to slide into tiny crevices to hide from predators or to seek for prey. Flatworms generally feed on small or sessile animals.

Leaf Slug (Elysia ornata)
Sometimes mistaken to be flatworms, this is actually a Leaf Slug (Elysia ornata). It feeds by sucking the sap of the Bryopsis algae, and is able to retain the chloroplast and use them for photosynthesis!

Hairy Sea Hare (Bursatella leachii)
AP found this little Hairy Sea Hare (Bursatella leachii). Seasonally common, we can sometimes find hundreds of them on some of our shores!

Funeral Nudibranch (Jorunna funebris)
I did not have much luck with nudibranchs for this trip, and only found 2 of them. The Funeral Nudibranch (Jorunna funebris) is a cute little slug that always reminds me of Snoopy when I see them.

Black-margined Nudibranch (Glossodoris atromarginata)
The Black-margined Nudibranch (Glossodoris atromarginata) was the other one I found. The term "nudibranch" means "naked gills", refering to the flower-like gills on the back of most species.

Mosaic Crab (Lophozozymus pictor)
We spotted a Mosaic Crab (Lophozozymus pictor) among the seaweed. This is the most poisonous crab in Singapore, and studies shown that the poison from one crab can kill as many as 42,000 mice!

Thunder Crab (Myomenippe hardwickii)
I had thought that Thunder Crabs (Myomenippe hardwickii) feed only on shells by cracking them with their huge claws, but apparently they catch fish too! In fact, the little fish it had in its left claw was still alive when I witness this scene.

Porcillopora Crab
There were quite a number of Cauliflower Coral (Porcillopora sp.) colonies, and I found little crabs living in many of them.

Mole Mushroom Coral (Polyphyllia talpina)
Cyrene Reef also has many mushroom corals. The above is a Mole Mushroom Coral (Polyphyllia talpina). It is a colony of many coral animals actually, and not just a single animal! The little tentacles you can see above belong to many tiny coral animals called polyps.

Sea Anemone
SY spotted this sea anemone that was somehow out in the open, instead of being attached to any hard surface or had its body column buried in the sand.

Soon, tide was rising and it was time to go. On my way back to the boat, I came across this disused quadrat lying among the seagrass. I was contemplating whether I should take it back with me to dispose it properly, but I noticed it had already became a micro-habitat with a colony of zoanthids stuck to one corner, and various algae, seagrass and sponges etc stuck to various places. I didn't want to kill those marine life, so decided to just leave it there.

On the whole, it was great to be back at Cyrene Reef!

Sunday, April 26, 2009

Checking out Tanah Merah

Decided to visit a part of Tanah Merah shore which we have not visited before with LK and ST. While the beach was enclosed within a rock bund, there were still quite a number of interesting things to see!

Acorn Worms (Class Enteropneusta)
Acorn Worms (Class Enteropneusta) were quite abundant on the sandy shore here, and the above is the cast of one of them. They feed on tiny organic particles in the sand by swallowing the sand and process the edible bits. The remaining sand is push out of its backend, forming the coil of sand.

Boulder Hard Corals
Several small colonies of Boulder Hard Corals could be seen in the tidal pools here. Like most hard corals, we can usually only see the small coral animals (aka polyps) when the colony is underwater. The hard structure is made by the polyps with calcium carbonate. The tiny little dots you see on the coral above are the "doorways" to the individual "homes" of the polyps!

Horned Ghost Crab (Ocypode ceratophthalma)
We found this Horned Ghost Crab (Ocypode ceratophthalma) holding onto a fish, and the fish was still alive! This crab usually only come out at night, and while it does hunt for food, it is also a scavenger.

False Limpet (Siphonaria atra)
This flattish object stuck to the rock is actually a snail - a False Limpet (Siphonaria atra). While it is found on the shore area, it does not have gills and breathe with lungs instead. The flattened, shield-like shell allows it to hold tightly to the rocks and prevent it from being dislodged by the waves.

Have asked SK the ID for this snail before, but again, left it in office! Will have to check when I'm back and update later. In any case, was really glad to see one that was still alive - the last one I saw was just a dead shell. Update: This is a Trigonostoma scalariformis.

Clithon Nerites (Clithon oualaniensis)
This shore also has plenty of little Clithon Nerites (Clithon oualaniensis) with rounded shells, and somehow many of them stuck themselves to the plentiful creeper shells (probably Batillaria zonalis).

Angaria delphinus
This may appear to be a rock...

Angaria delphinus
But it is actually a snail! This is probably Angaria delphinus from the Family Trochidae. The other place which I have seen this was Semakau, but they are probably more common than that, just that being so well-camouflaged, most people tend to miss them.

Fan Worm (probably Sabellastarte indica)
Several pretty Fan Worms (probably Sabellastarte indica) were also found. They feed by collecting plankton or tiny organic particles in the water with their tentacles.

Sea anemone
Found this unknown sea anemone on the sandy shore.

It's always interesting to watch a flatworm sliding among the rocks and seaweed. Being so flat, it easily slides through tiny gaps, and is always so graceful while doing that!

Penaeid Prawn (Family Penaeidae)
This small Penaeid Prawn (Family Penaeidae) was being very cooperative and I had quite a few shots of it.

I have no idea what shrimp this is, but it sure looks pretty!

Halfbeak (Family Hemiramphidae)
The tidal pools were really great for taking photos of fishes, and we found many of which we couldn't identify. The above is a halfbeak (Family Hemiramphidae), but I have no idea of the exact species.

White-spotted Rabbitfish (Siganus canaliculatus)
Several juvenile White-spotted Rabbitfish (Siganus canaliculatus) were seen hiding under seaweed and near rocks. This fish is very popular during Chinese New Year, as it coincides with the fish's breeding season and the roe is considered a delicacy by many Chinese.

Striped Eeltail Catfish (Plotosus lineatus)
One huge school of Striped Eeltail Catfish (Plotosus lineatus) were swimming around the tidal pool, forming interesting formations along the way. This fish has a venomous spine on its dorsal fin, and one on each of the pectoral fins too, which can sting very painfully.

Flower Crab (Portunus pelagicus)
A little Flower Crab (Portunus pelagicus) was found among the pebbles and snails. This crab can swim very well with its paddle-like back legs.

Blue hermit crabs
LK found these little blue hermit crabs clinging onto a piece of rope. Have no idea what species they are. (Update: these are Clibanarius merguiensis. Thanks to Yoyo for the ID!) The only other blue hermit crab I have seen are the Blue-striped Hermit Crabs (Clibanarius longitarsus) usually found in or near mangroves, but these do not have stripes, and the colours of the eyestalk and antenna are different too.

White-spotted Reef Hermit Crab (Dardanus megistos)
A pleasant surprise will be this White-spotted Reef Hermit Crab (Dardanus megistos). This hermit crab is more commonly seen on coral reefs.

Land Hermit Crab (Coenobita sp.)
On my way back out of the shore area, I saw several Land Hermit Crabs (Coenobita sp.), but unfortunately they're all really camera-shy.

On a whole, this was a really good trip, and I do hope to find time to come back again!

Thursday, April 16, 2009

Pasir Ris Park with Temasek Junior College on 15 Apr 2009

After helping out with guiding at Chek Jawa, I headed to Pasir Ris Park to give a guided walk for Temasek Junior College students. Since I was early, I managed to take a walk around the park while waiting for the students to arrive.

Zebra Doves (Geopelia striata)
A pair of Zebra Doves (Geopelia striata) were spotted near Sungei Tampines. These small doves feed on small grass and weed seeds, though at times it may also feed on small invertebrates.

Grey Heron (Ardea cinerea)
Standing in the middle of the river was a Grey Heron (Ardea cinerea). One of the biggest bird in Singapore, it feeds on fishes and other small animals.

Lenggadai (Bruguiera parviflora)
The few Lenggadai (Bruguiera parviflora) trees were blooming, but unfortunately none had formed seedlings yet. This tree is said to produce good firewood and charcoal. The seedling is sometimes eaten as a vegetable.

Bakau Putih (Bruguiera cylindrica)
The Bakau Putih (Bruguiera cylindrica) is one of the most common mangrove trees found at Pasir Ris. Several of them were flowering too. Interestingly, the wood from this tree is said to produce an odour that repels fish, and thus it was not used to make fish traps.

Bakau Putih (Bruguiera cylindrica)
Here's the seedling of the Bakau Putih.

Tumu (Bruguiera gymnorhiza)
The Tumu (Bruguiera gymnorhiza) was not as common as the Bakau Putih, but there's a fairly healthy population at Pasir Ris. The hard, red wood from this tree can be used to make furniture, house posts and also used for firewood and making charcoal.

Ceriops zippeliana
The Ceriops zippeliana was easily spotted in many parts of the mangrove. It can be differentiated from the other Ceriops species by the red collar on mature seedlings.

Nyireh Batu (Xylocarpus moluccensis)
In other mangroves in Singapore, the Nyireh Batu (Xylocarpus moluccensis) is not very commonly seen, but there is a good population here at Pasir Ris.

The students soon arrived, and we took a walk around the Mangrove Boardwalk.

Cotton Stainer Bugs (Dysdercus decussatus)
Among the first animals we saw was a horde of Cotton Stainer Bugs (Dysdercus decussatus) on a Sea Hibiscus (Talipariti tiliaceum). These bugs feed on the seeds of the Sea Hibiscus.

Thespesia Firebugs (Dysdercus simon)
Not too far away, we saw several Thespesia Firebugs (Dysdercus simon) on a Portia Tree (Thespesia populnea). This bug is less common then the Cotton Stainer, and can be differentiated from the latter by its black head.

Praying Mantis (Order Mantodea)
A juvenile Praying Mantis (Order Mantodea) was resting on the leaf of a Sea Hibiscus.

Sea Holly (Acanthus ilicifolius)
This Sea Holly (Acanthus ilicifolius) has pretty lilac petals, which can be differentiated from other species with white flowers.

This is probably a Lacewing (Family Chrysopidae).

Atlas Moth Caterpillar (Attacus atlas)
I saw a few trees with the caterpillar of the Atlas Moth (Attacus atlas)! This moth is believed to be the largest moth in the world based on total wing surface area.

Atlas Moth Cocooon(Attacus atlas)
A few had gone into the pupa state, hiding in a cocoon. In Taiwan, these cocoons are made into pocket purses.

Face-banded Sesarmine Crab (Chiromantes eumolpe)
Some students spotted this pretty Face-banded Sesarmine Crab (Perisesarma eumolpe) which had deep red claws and an iridescent green band on the face.

Tree-climbing Crab (Episesarma sp.)
Another crab we saw was the Tree-climbing Crab (Episesarma sp.). During high tide, they will climb up the trees to stay away from predatory fishes that comes in with the tide.

Giant Mudskipper (Periophthalmodon schlosseri)
The Giant Mudskipper (Periophthalmodon schlosseri) is the biggest mudskipper found in Singapore. It is a fish, but is able to survive out of water by storing water in its mouth and gill chamber. When its skin is wet, it can breathe through its skin too.

Bakau Kurap (Rhizophora mucronata)
Another mangrove tree we saw was the Bakau Kurap (Rhizophora mucronata). This tree produces big and long seedlings, which were used by natives in the region to cane children who misbehaved.

Little Heron (Butorides striatus)
One of the students noticed this very well-camouflaged bird - a Little Heron (Butorides striatus). It eventually managed to catch a fish with its beak!

Malayan Water Monitor (Varanus salvator)
The Malayan Water Monitor (Varanus salvator) is one of the biggest lizard in the world, and it is very common in Singapore. This lizard is mildly venomous. While the weak venom may not kill, these lizards harbours lots of bacteria in its mouth that can cause serious infection if you are bitten by it.

Here's a quick group shot.

Cicada (Family Cicadidae)
There were lots of male Cicadas (Family Cicadidae) singing in the mangrove forest. Studies shown that they sing a different song for different purposes, such as courtship songs or distress songs.

Red Jungle Fowl (Gallus gallus)
We soon ended the walk, and as we walked out of the mangrove area, we saw a few Red Jungle Fowls (Gallus gallus). This chicken is often believed to be the direct ancestor of the domestic chicken.

Laced Woodpecker (Picus vittatus)
Yet another pleasant surprise was 3 Laced Woodpeckers (Picus vittatus), my first time seeing them, even though this species is supposed to be common in Singapore!

That certainly gives the guided walk a very nice closure! Hopefully all the students enjoyed the walk with me!