Accidentally Hantu

6am and we're off. We were originally planning to go to Cyrene but alas, there were boat problems so to Hantu we went instead. No it's not lightning striking the petrochemical plants. It's daybreak over Pulau Bukom which lies just opposite Pulau Hantu.Despite the proximity of major industrial installations, the shores of Hantu are very much alive. With these humungous soft corals which seem to keep multiplying!Each large soft coral, that remind me of fried eggs, is actually a colony of tiny polyps that look like miniature sea anemones with a body column topped by branching tentacles. The polyps live in a shared leathery tissue.

Pulau Hantu is also full of hard corals. They come in a variety of colours and shapes. Hard corals are also a colony of tiny polyps, but each polyp creates a tiny hard skeleton called a corallite. Each colony is made up of the joined up corallites of countless polyps.This is a pink plate-like Turbinaria sp. coral.A pretty green boulder-shaped coral with ring-shaped corallites. I don't know what kind of hard coral this is.A beautiful branching Acropora sp. coral. This kind of coral is rather rarely seen on our intertidal.
And a blue mushroom hard coral (Family Fungiidae). Unlike most other hard corals, most mushroom hard corals are a single polyp!Another mushroom hard coral, Heliofungia actiniformis. It is also a single large polyp with long tentacles ending in white rounded tips.

Just to make things confusing, there's the Blue coral (Heliopora coerulea). The coral isn't blue and it isn't a hard coral even though it has a hard skeleton. Their internal skeletons are blue, hence their common name. The blue colour is due to the iron salts that are incorporated into their skeletons. On the outside, they are usually brown because the thin layer of living tissue that covers the outer surface of the skeleton is brownish.The tiny polyps have eight tentacles with fine branches like other soft corals. Thus they are grouped with other soft corals. True hard coral polyps have smooth tentacles in multiples of six.

Blue corals are considered living relicts of fossil species known from more than 100 million years ago. Most other corals have an evolutionary age of only several hundred thousand years. Blue corals used to be dominant before the last Ice Age when the seas were warmer.

There are indeed a bewildering variety of hard and soft corals on our shores!And all kinds of other marine life crowd the shores of Pulau Hantu.
Pulau Hantu is a great place to see large sea anemones still common on our reefs. The Magnificent anemone (Heteractis magnifica) is in the photo on the right, and the Giant carpet anemone (Stichodactyla gigantea) is on the left. Both these anemones usually host clown anemonefishes and anemone shrimps. Unfortunately today, I didn't see any. Although Annabelle saw one anemonefish. I do hope this doesn't mean something negative is happening to the shores.

There were also lots of Phymanthus sea anemones with branching tentacles, and the odd star-shaped sea anemone that is NOT Condylactis.

But here's one sea anemone that I've not seen before.Could it be a Bulb-tipped sea anemone (Entacmea quadricolor) with 'deflated' tentacle tips?I don't really know.

A good reef is also a great place to find nudibranchs. And today, all the usual suspects were present.The phyllids are lumpy little nudibranchs without an external gill. The one in the left photo is Phyllidiella pustulosa and the one on the right is Phyllidiella nigra. These two nudibranchs are quite commonly encountered on our reefs. Nudibranchs are generally unpleasant or toxic to eat and advertise this with bright patterns or colours.Also commonly encountered is the frilly lemon yellow Glossodoris atromarginata, and the nudi-in-pajamas Chromodoris lineolata.

In fact, Glossodoris atromarginata was so abundant they were seen in groups, appearing rather sad and blob-like out of water during the low tide.I almost missed the Hairy crab (Family Pilumnidae) that was right on top of this Glossodoris atromarginata. Was it about to eat the nudi? The Hairy crab is known to eat toxic animals such as zoanthids. I didn't find out as the crab quickly scuttled away.

Here's a strange sign on the sea wall of Pulau Hantu.This is rather odd as Pulau Hantu is one of the favourite dive spots in Singapore with many exciting dives conducted by the Hantu Bloggers. And Pulau Hantu is the only site designated as a dive spot in the URA Draft Master Plan's Leisure Plan.

And just off Pulau Hantu, the humungous oil rig located off Pulau Semakau can be seen. Here's the MPA notice about the oil rig. Here it is in the distance with the seawall and reefs of Pulau Hantu in the foreground.On the way home, we take more photos of it. Here's indications of the locations of Pulau Semakau, Raffles Lighthouse (RLH) and Pulau Senang. Raffles Lighthouse and the Live Firing Islands of Sudong, Pawai and Senang have some of the last untouched reefs in Singapore. While Pulau Semakau has good natural shores. Let's hope this massive activity does not impact these nearby reefs. Here's a closer look at the oil rig.

On the way home, we have a faraway look at Cyrene Reef.It's a submerged reef so hardly anything sticks out.
Except the beacons to mark its location so ships can avoid it.

Let's hope we can go ahead with our plans to go to Cyrene tomorrow!

Andy shares a wonderful clip of an octopus he saw changing colours on the sgbeachbum blog

A happy day on Changi

6am and it's a super low tide on Changi! The early morning sandy shore was crawling with tiny hermit crabs and tiny little sand stars (Astropecten sp.).The hermit crabs obviously didn't quite like the sand stars. Sand stars are carnivorous and generally eat mainly snails and clams. But these sand stars are known to be unfussy about what they eat.Every now and then, a little hermit crab would nip at the tips of the sea star's arms. Then quickly run away!Like elsewhere, some of these sand stars had tiny little white snails on their arms. These are probably parasitic snails. Must be awful not being able to pick them off your arms.Another burrowing snail sometimes seen on Changi is this Olive snail (Family Olividae). This particular one seem to have survived a ferocious attack on its thick smooth shell. By a crab?The underside of the snail was still alright, and the animal itself seemed ok.

The seagrass meadows today seemed a little thin. There was also not much seaweed. There were plenty of large white sea urchins (Salmacis sp.) as well as many skeletons of these sea urchins. So perhaps the 'urchin season' is nearly at an end. There were also quite a lot of sand dollars (Arachnoides placenta).

There were many large carpet anemones but none I saw with anemone shrimps, not even tiny ones. Except for this one.Here's the big fat mama anemoneshrimp (Preclimines brevicarpalis).And the smaller, more transparent papa shrimp.

We also saw a large glass anemone and the hermit crabs had little anemones on their shells. But not many other kinds of sea anemones. In fact, there were also very few peacock anemones and sea pens. This is rather odd as this shore is usually teaming with these animals.

Kok Sheng had asked us to check on the situation with the Button snails (Umbonium vestiarum). And we found a patch of these tiny little snails!I've often been annoyed that these snails tend to float up when we try to take a closer look at them. Makes it difficult to photograph them. Siti mentioned that in some snails, the first chamber is used in flotation. We also noticed that the floating snails tended to stick together, forming 'rafts'.

Dr Dan remarked earlier that this is an important behavioural aspect. This may allow these snails to disperse to new areas quickly. Indeed, as I thought about it some more, it may also be a way for them to escape from predators. If they are dug up while submerged, they float straight up away from the ground thus escaping nasty predatory snails and other animals that can't swim.As we observed the raft of snails, one by one, the snails would sink and quickly burrow back into the sand. The snails have tiny little eyes on stalks, and a long leaf-like foot. Amazing!

A first-time encounter for me was this strange black fan worm with white spots on its feathery tentacles.And what a marvellous surprise! Chay Hoon finds a feather star! A first time for me on Changi.Today we also came across the strange green sea star that was first mentioned in the manta blog in April and again in May. The big white patch is an injury to the sea star.Here's a closer look at the upper side. The big 'knobs' are made up of tiny bumps. Something had taken a nibble off the top of this poor sea star.And a look at the underside. It has pale pink tube feet with suckers at the tips. We have no idea what kind of sea star this is!

Besides the sand stars, we didn't see any other kind of sea stars on this shore. But there were lots of thorny sea cucumbers (Colochirus quadrangularis), buried ball sea cucumbers (Phyllophorus sp.) and smooth sea cucumbers, some warty sea cucumbers (Cercodemas anceps), one transparent sea cucumber (Paracaudina australis) and the strange beige sea cucumber that looks like sand.

The edible animals seemed particularly scarce today: no Sandfish sea cucumbers (Holothuria scabra), few Gong-gong (Strombus canius), few Fan shells (Pinna sp.), no horseshoe crabs.

There were lots of people out on the shore especially after sunrise.
Some were just looking around.
Some had plastic bags collecting stuff. I couldn't get to see what as they avoided me, but Siti saw someone with some Fan shells. I also came across piles of large Window-pane shells (Placuna sp.) that looked like someone collected them and then changed their minds. In the distance a man with a changkul digging for worms, probably for fishing.There was much fishing going on at the shore. We had to step over many lines strung out on the shore in the morning. And the team gathered some abandoned lines on the shore. There was also a group of fishermen on an inflatable boat off shore. Later in the morning, one went out into the incoming tide with a cast net.

There was also a big group camping on the shore, probably because tomorrow is a school holiday.Thus it was very heartening to come across one guy walking out onto the tidal flats to RETURN these two amazing snails! We asked if we could take photos of them and he let us have them.On the left, a large and living Bailer snail (Melo melo) and on the right, a lovely Noble volute (Cymbiola nobilis). Both these snails are listed among the threatened animals of Singapore due to habitat loss and over-collection.

From Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Bailer snail is "thought to have been exterminated from our waters, but a recent isolated sighting confirms their continued presence". While the Noble volute is "confined to the region, particularly Singapore and southern Peninsular Malaysia, presently uncommon on our reefs although abundant in the past".

The Bailer snail was very much alive, although it seemed a little slow. The Noble volute was perfectly fine. Our last encounter with someone collecting a Bailer snail had a less happy ending.After checking on the snails, Samson and HB took them far out into the water to release them. Hopefully, they will be safe from collectors.

What a wonderful way to end a great day out on Changi!

More about this trip and the Melo melo on the manta blog.

BB specials

4am and we're off to BB. This marvelous shore has made some recovery from the flood of 2007 and the team saw lots of special finds thanks to many keen eyes. I'm too slack to post about them all and shall leave it to the rest of the team to post...heh heh.

Here's some of the finds I thought was special.

BB is the only place where I've seen these ball-shaped soft corals in numbers. (They are possibly members of Family Nephtheidae). They used to be plentiful before the flood, then disappeared, but today have made a fully recovery with lots of large colonies, some 30cm across or more!
Each ball is a colony of many tiny polyps which have tiny branched tentacles. The polyps lie at the tips of thick fat short branches.This is what a colony looks like when it is submerged.The cavities formed by the branches of the colony form a snug home for white snapping shrimps! There's usually a pair of these shrimps in each colony. Here's one swimming about in the submerged part of the soft coral. Here's a closer look at a snapping shrimp that was on the outside of the soft coral.The shrimps are often peeking out when the soft coral colony is collapsed out of water. But the shrimps are so well camouflaged that it's hard to spot them. Can you see the two shrimps in the photo above?Well, I didn't either until I got home and processed the photo!!For some reason, I saw a tiny Kite butterfly fish (Parachaetodon ocellatus) near two of these soft coral colonies. Under the colonies other small animals also find shelter such as little crabs and fishes, and the ordinary burrowing snapping shrimps. So these soft corals appear to have an important role on this shore.

Other first time encounters for me included this pretty snapping shrimp that is very different from the usual ones that I see on our other shores.It has a really handsome tail and white bands on a slim body. I have no idea what it is.

I also came across this really odd creature with really scary-looking tentacles that appeared to be studded with stingers .As I was observing it, it suddenly contracted.It seemed to have caught a little fish. It does seem to be a sea anemone. But what an odd-looking tentacle structure!

There were also several strange peacock anemone-like animals that I've not seen elsewhere. Peacock anemones (Order Ceriantharia) have two rings of tentacles, an outer ring of very long ones, and an inner ring of short ones.
Here's one that doesn't look like anything I've seen before, with a ring of very short inner tentacles.And another one also with an inner ring of very short tentacles, holding two of its outer tentacles upwards. What strange behaviour.

Lots of other amazing creatures were seen today. Joe Lai saw a moray eel, nudibranchs and other critters, Dr Chua found seahorses, November spotted lots of sea urchins, sea stars and other critters, Chay Hoon of course got us lots of slugs, Sam found a special sea star! There were stars in abundance, octopus, special snails and more!

Let's read all about these on the blogs by the other team members!

• Kok Sheng's wonderful creations blog nudis, sea stars, bailer snail, moray eel and more!
• Sam's ramblings of a peculiar nature everything and more!
  

Sekudu Survey

3am and a small team were off to check out Pulau Sekudu which lies just off Chek Jawa. The island is now part of the Chek Jawa Wetlands and requires a permit to visit. We were eager to see how this added protection would have affected the marine life there.

The seagrasses were doing well, with lots of healthy carpet anemones of various sizes. Tiny sea pens were seen, although the more common ones with the orange 'root' were not encountered.There were little sand stars among the meadows, as well as a few white sea urchins (Salmacis sp.) and black sea urchins (Temnopleurus sp.).This is my first time seeing the black sea urchin on Sekudu. However, we didn't see any pencil urchins (Prionocidaris sp.) this time around.

It was generally 'quiet' compared to earlier visits. Most of the coral rubble was bare, until the tide fell very low. It was only then that the kind of sponge and encrusting growths that we used to see in the past were revealed.
Sponges are not only pretty but also provide places for animals to shelter. Like this bunch of many little hermit crabs.I have no idea what kind of hermit crabs these are.

Nudibranchs also feed on such encrusting animals and thus more common where there are good growths. So happily, Chay Hoon finally found her nudibranchs after going slugless for two days of field trips.

The coral rubble was infested with the little brown sea anemones that used to be common but disappeared after the flood of 2007.These little sea anemones are not only back, but I also noticed that there were green ones among the brown ones too! Are they just different coloured versions or entirely different kinds of anemones?

We looked for Knobbly sea stars (Protoreaster nodosus) and altogether we saw five. We also saw several Biscuit sea stars (Goniodiscaster scaber). But all these stars were adults.

It's good to know that at Changi yesterday, we saw lots of baby sea stars. Lying just across from Pulau Sekudu and Chek Jawa, Changi can be a source of new recruits should anything happen to these Ubin shores.

Chay Hoon found this four armed Crown sea star (Asterina coronata)!
Jeff annouced happily "Didn't you know Ria, fore warned is for armed?"... groan.

Our trip was disrupted for a while by a rain shower, so we didn't really explore thoroughly. Some parts of the shore was thick with stinging hydroids, but I could only find one of these beautiful pink soft corals.On our visit last year, we encountered canoeists who came to Sekudu to remove these soft corals. Let's hope the new measures in place to restrict access to Sekudu will reduce such losses.

Among the special encounters was this pretty moon snail.We've seen this moon snail on Changi too and a kind reader suggested it might be Tanea euzona.

Dr Chua found this amazing sand dollar! First one, then another!It was pink! This might be Peronella lesueuri which is listed in Dr Lane's book (Lane, David J.W. and Didier Vandenspiegel. 2003. A Guide to Sea Stars and Other Echinoderms of Singapore. Singapore Science Centre. 187pp.) According to the Guide: "This species is not common in Singapore waters. In recent years, it has been dredged only south of the mainland and then only occasionally."

But the most stunning encounter for me was Nemo of the North!Originally thought not to exist on our Northern shores, I was quite surprised to find this False clown anemonefish (Amphiprion ocellaris) on Pulau Sekudu!

Unfortunately, clown anemonefishes have been harvested from the wild for the aquarium trade. So much so that they may become locally extinct. Here's more about the situation in Australia. Let's hope this little Nemo and her friends on our other shores are left alone in the wild.

Although there were fewer fish traps on the shores compared to our last trip, we saw an abandoned driftnet stuck among the rocks.We also saw a fisherman lay a drift net in the channel between Pulau Sekudu and Chek Jawa. I hope all these dangers will not hurt Nemo and all the marine life on this precious little island.

More about encounters on this trip on Kok Sheng's wonderful creations blog.