Sunday, July 29, 2007

Sekudu with the Sea Anemone Team

Today, the Sea Anemone Team was out on our shores again seeking anemones! This time, our destination was Pulau Sekudu.

One of our main objective today was to find this little reddish brown anemones that look like zoanthids.

The team easily found quite a number of them at the coral rubble area, but collecting them turned out to be much less easy.

As the anemones were firmly attached to the rocks, the team had to do a lot of digging to get the rocks out, or try to break off the part of the rock that had the anemone attached.

Luckily, I had a much easier job removing the one below.

It was attached to a small piece of rock, and so I easily picked the entire piece of rock and gave it to Dr Daphne's assistant :P

There were other species of anemones around, but we didn't have to collect them because they were more well-studied or the team already had enough specimens.

There were a number of Haddon's carpet anemones (Stichodactyla haddoni), thought much, much fewer than those days before the freshwater floods in January.

Several swimming anemones (see above) were spotted among the seaweeds too. I remembered handling one of these anemones last year at Pulau Hantu, and it started dropping its tentacles, and I felt really guilty about it. Was reading the Wildfilms blog just now and understand that these swimming anemones can drop off their tentacles on purpose if they are scared. Luckily, each tentacle can eventually regenerate into a complete new swimming anemone! But note that this is some what uncommon among anemones, and in fact most anemones can't do this.

There were lots of pretty peacock anemones in the shallow waters, but as these were not true anemones (they were from a different order), the team did not collect any of them.

Alvin spotted this little nudibranch, and asked me to help hold the lights while he took a few shots.

It's an Atagema intecta, which feed on sponges. But while we were filming, I noticed another colourful blob on a nearby rock.

It's another nudibranch!

Had initially thought that it's a Hypselodoris kanga, which can also be found on our shores. However, after a check at Sea Slug Forum, I think it's most probably a Hypselodoris infucata instead.

The gills of the H. infucata are simple two dimensional leaf with a red line along the internal and external edge. H. kanga's gills are triangular in cross-section, which means there're three edges to each gill, one on the inside and two on the outside.

Apart from the wildlife that we spotted above, I also saw a few geographic seahares, lots of salmacis sea urchins, many swimming crabs (a few were even mating), thunder crabs etc.

But still, what I've seen today was hardly even a shadow of what we got to see at Pulau Sekudu before the flooding in January which destroyed much of the wildlife of our northern shores.

Things were certainly improving, and we were seeing signs of recovery here and there. But when will our northern shores return to their former glory? And what if we get another massive flooding again this December?

Dr Dan, who visited Chek Jawa in February this year, had told me during his visit that he's sure things will come back, but we must be prepared that not all of them will come back, and in fact, we may see new things showing up. That was because after the flooding, the habitats were changed.

So far we haven't seen any knobbly sea stars at both Chek Jawa and Pulau Sekudu after the flood. Will they come back? Or will some new things replace them?

Only time can tell, I guess. But I certainly miss those beautiful sea stars...

Saturday, July 28, 2007

Sisters Island with the Sea Anemone Team

Finally got to go with Dr Daphne and the sea anemone team today!

It was certainly a very fun and enriching experience. The island we visited today was Sisters Island.

Dr Daphne was here in Singapore to help study and identify the various species of sea anemones we have here.

Our job today was basically to seek for anemones and collect those that we have not gotten enough specimens for the study.

Here's Dr Daphne and gang trying to remove one of the anemones using this long equipment that I couldn't remember the name :P (Update: Found out from Ria that it's called a Yabby Pump! Cool name right?)

It was quite a good day, and we found several species of sea anemones. The one below is a Phymanthus sp. which we collected a few specimens at the coral rubble area.

In a more sandy area of the coral rubble, I found this pretty star-like anemone. We tried to remove it but wasn't successful, as it was very quick and retracted into the sand before we could get it.

On the sandy upper shore, we found many of these anemones that had a long column. Wonder if they were of the same species as the ones we found at Changi?

Apart from these smaller anemones, we found the much bigger (in fact, bigger than your face) merten's carpet anemone too. And what a pleasant surprise we had!

There were anemonefishes on all 3 merten's carpet anemones I found today!

Besides the bigger female, there were several smaller males as well! There are two of them in the above picture, can you find them? One of them was very well-hidden among the tentacles.

While the main focus was sea anemones, we also encountered many other interesting animals along the way, and here are some of them.

While anemonefishes were cute, we had the more dangerous fishes too, such as the blue-spotted fantail ray above. There were many of them in the lagoon, and some of them were half buried under the sand, and so we had to really watch where we stepped.

Now, is that a rock or a living thing? It is actually a living shell called the spider conch! This master of camouflage even had little soft corals growing on its shell. Isn't this amazing? But sadly, this huge snail is becoming rather rare in our waters as they were collected for the cooking pot, and the were also suffering from the lost of habitat. Hopefully things will improve when Singaporeans are more educated about the richness and the fragility of our natural heritage.

This snail that has a smooth and pretty shell is called a moon snail. They usually hunt just beneath the sand for little shells.

Several snapping shrimps were out hunting too! These shrimps have one huge pincer which can produce explosive sounds to stun its preys like little fishes and other animals. If you hear any popping sound along a beach, especially when it's dark, it's probably them!

The were many pretty gobies too.

Chay Hoon found a synaptid sea cucumber among some rocks. Understand that "synaptid" actually means sticky, as these sea cucumbers has a sticky outer surface.

I also saw this little brittle star sliding over the sand surface by wriggling its arms. Like their relatives the sea stars, brittle stars are able to regenerate lost arms too!

And at the water's edge, there were several moon crabs gliding over the sand effortlessly with its paddle-shaped legs. As I approached one of them, it immediately burrowed into the sand in a split second!

Eventually, the tide was getting high and we had to make a move.

Hopefully after Dr Daphne's study, we will have a better understanding of the various sea anemone species in our waters.

There are just so many things about our living shores which we still don't know. Certainly hope more experts will come to Singapore to study the various wildlife we have.

But more importantly, I certainly hope our nature places will be properly preserved so that such studies can be conducted in future, and also, our future generations will get to experience the wonderful natural heritage of Singapore!

Monday, July 16, 2007

Hunt & Seek at Semakau on 15 July 2007

Finally, back to Semakau again! We had two very rainy walks last month, but thankfully the weather was superb last Sunday.

This time round, however, my role was different - I was the hunter-seeker!

This was my first time being a hunter-seeker at Semakau. I'm usually the guide. And what made this trip so special was, we started around 5 plus in the morning!

First time doing hunting-seeking, and some more had to do it when it was still dark! That was really quite a challenge.

First of all, how to find my way through the usual route to find the usual stuff when I could hardly see the landmarks? Progress was thus really slow in the beginning, as I had to try to find my way to the usual spots.

Even after finding them, there's another problem - how are the guides going to spot the route markers in the dark?

Fortunately, HSBC was also there conducting a walk, and as they had lots of volunteers, they were able to provide station masters. Thus, for the first few stations, we had station masters manning the stations.

My first task was to find the sand sifting sea stars (Archaster typicus). Many of the sea stars have migrated to the other side of the lagoon, but I was really hoping that I could find it at the usual spot before we cross the seagrass lagoon, so that the guides could talk about the colourful sponges there at the same time.

Was also worried that the sea stars on the other side of the lagoon may be harder to find as they could be some way off the usual route that we took. But luckily, I managed to find several of them just before we enter the seagrass lagoon.

And as it turned out, there were many of them right near the exit of the seagrass lagoon as well. So many of the visitors got to experience them twice.

As a sea star uses sea water to support its body and move its little tube feet, it is thus very stressful for them if you take them out of sea water for too long. So please remember not to take your time to admire it while holding it in your hand or a dry container!

After crossing the lagoon, the next task was to find the sandfish sea cucumber. This proved to be rather easy as well, as a huge one was right there a short distance in front of us. Apart from the sandfish sea cucumber, thanks to the other guides and HSBC volunteers, we found several other sea cucumbers too!

From top left going clockwise, we had the sandfish sea cucumber (Holothuria scabra), the stonefish sea cucumber (Actinopyga lecanora), the giant synaptid sea cucumber(Family Synaptidae), and the dragonfish sea cucumber (Stichopus horrens). The sandfish, stonefish, and dragonfish sea cucumber are all edible, though they must be properly treated to remove the toxins.

My next task was to find the onch slugs (Onchidium sp.), but as I was making way to the rocks where they were usually found, I saw a trail in the sand. Putting my hand into the sand at the end of the trail, this was what I scooped out.

It's a lovely moon snail (Family Naticidae). Moon snails usually hunt just underneath the sand surface for other little shells. You can see it has a smooth and beautiful shell, as it has a large foot which often wraps around its shell, and thus prevents it from being scratched. I placed the moon snail near the sandfish sea cucumber and moved on to find the onch slugs.

And there they were, feeding on the algae on the rocks. These slugs come out when the tide is low, as they actually breathe air with a simple lung modified from a section of the mantle cavity. The lung opens through a pore alongside the anus at its back end below the mantle.

More closely related to the land snails than the sea slugs, these slugs are thus also called marine pulmonate slugs as they are classified under the Order Pulmonata (in latin, ‘pulmo’ means lung). Most onch slugs hide in air pockets among rocks during high tide, but it was noted that some can also breathe a little through its skin (or mantle) under water. These slugs thus have to remain inactive during high tide so as to survive on that little oxygen they are getting.

Happen to chance upon an article which says that some onch slugs actually follow a mucous trail home after each feeding expedition. Does that mean that if you remove an onch slug from the rocks, then put it back on a different spot, it may not be able to find its way home.. and may... drown when the tide rises??? Oh no... that's a horrifying thought.

Anyway, on to my next target - knobbly sea stars (Protoreaster nodosus).

Found one of them quite quickly, and later one of the HSBC volunteers and one of the guides also found one each. These are among the biggest sea stars that can be found in our waters!

And just when I was setting up the sea star station, one of the NEA staff shouted to me that he found a sea urchin!

Some how he managed to scoop it up without getting free injections. It was a long-spine sea urchin (Diadema setosum). These sea urchins have long, sharp and brittle spines which break easily, so don't handle with bare hands! They normally graze on algae and also scavenge.

Moving on, I found what I think should be a mole mushroom coral (Polyphyllia talpina), which I forgot to take a photo, but you can see it at July's blog. Anyway, here's another type of mushroom coral I found - a sunflower mushroom coral (Heliofungia actiniformis).

Under the mole mushroom coral and most other hard corals, the sunflower mushroom coral is a single living animal, and don't live in a colony.

There were lots of soft corals too, including the omelette leathery soft coral (Sacrophyton sp.) below.

Unlike the mushroom corals which are hard corals, soft corals don't have hard skeletons, but instead, the polyps are connected by a soft tissue mass.

As I seek for interesting things among the corals and other marine life, I noticed that there seem to be lots of little octopuses (Order Octopoda).

I tried many times to catch the ones I saw, and finally managed to get the one above into a pail with help from some of the HSBC volunteers.

And not far from where I caught the octopus, I found one of its distant relative - a fluted giant clam (Tridacna squamosa)!

A giant clam harbours symbiotic algae in its mantle. During day time, the clam spreads out its mantle to allow the algae to receive the sunlight they need to photosynthesize. The clam will then obtain nutrients from the algae.

After finding all these bigger things, I was really hoping to find some of the smaller ones. Found quite a number of the Acanthozoon flatworms, but just couldn't seem to find any nudibranch!

Some how, I think I just need to get the engine to spot nudibranchs started.

Chay Hoon and Juanhui soon found a pustulose phyllid nudibranch (Phyllidiella pustulosa) which they show me. And somehow after this, I started spotting quite a number of nudibranchs too!

I saw several pustulose phyllid nudibranch too (above left) and one marginated glossodoris nudibranch (Glossodoris atromarginata).

The name nudibranch actually means "naked gills", which you can see on the back of the marginated glossodoris nudibranch (the flowery thing). One interesting fact about nudibranchs is that they are simultaneous hermaphrodites, meaning each of them has both male and female reproductive organs. They usually fertilise each other when they mate, though sometimes, one may take on a male role, and the other a female role.

While I was searching for the nudibranchs, I also saw this beautiful anemone. It was quite big, about the size of a huge merten's carpet anemone or magnificient anemone. This is the first time I'm seeing this, so perhaps someone can enlighten me on the species?

Anyway, sea anemones are related to corals and jellyfish. An anemone has stinging cells in its tentacles that can paralyse animals that got too close to it. The animal will then be moved to its mouth in the centre using the tentacles.

Apart from the huge unidentified anemone, we also found a carpet anemone (Stichodactyla sp.)

In a little nearby pool of water was an anemone shrimp (Periclimenes brevicarpalis). it will probably return to the anemone when the tide is higher.

Finally, it was time to go back. While I was cutting across the rubble area, I saw this cute heart cockle (Corculum cardissa).

Unlike most other clams which have their valves flatten like plates, this clam has its opening of the valves cutting across the centre of the 'heart'! It's no wonder that some people collect this shell while it is still alive, kill it and make the shells into little gifts. If the lovers knew how heartless the way their so-called "token of love" was made, will they still see it as a "token of love", I wonder?

All in all, it had been a very good trip with lots of interesting finds. Hopefully I didn't fare too badly playing the role of the hunter-seeker for the first time at Semakau :)

Back to Changi

Finally found time to blog :P

Last Saturday, while the Wildfilms gang were off to Beting Bronok, I was back at Changi Beach, but this time round, with the Semakau gang and 2 friends.

Seems like the ball sea cucumber were making a healthy recovery, and this one below was in fact one of the first few animals I spotted at the beach.

During the monsoon season in January, the high rainfall resulted in the Johor River overflowing and flooding our northern shores with too much freshwater. Many marine organisms which live on saltwater died. I could still remember seeing thousands of dead ball sea cucumber at Chek Jawa...

The situation has certainly improved tremendously, and we are beginning to see more living ball sea cucumbers on our northern shores.

Changi is also one of the best places to find sand stars.

Sand stars are able to burrow into the sand to hunt for little seashells and also to hide from predators.

There were lots of moon crabs too.

Moon crabs has paddle-shaped legs which allow them to slice into the sand in a flash. the legs allow them to swim quickly too.

I was really hoping to find a seahorse, but instead, we found lots of its relative - the pipefish.

Like the seahorses, male pipefishes carry the eggs in a pouch until the baby fishes hatch.

And somehow, our northern shores are often visited by several types of sea hares, including the geographic sea hare below.

Sea hares got their name from the projections on their front ends which somewhat resemble rabbit ears. They are closely related to snails, and thus they have soft bodies, but they have an internal shell instead of an external one, like the moon snail below.

A moon snail has a large foot which often covers over the shell, and thus prevents the shell from being scratched. The moon snail shell is thus usually very smooth. Moon snails often hunt just beneath the sand for little shells. They secretes an acidic fluid to soften the shells before it drill through it with its radula (something like a tongue). The little shell animals are thus eaten within their shells!

On one of the sand bars, I noticed lots of round-shaped prints on the sand. Putting my hand under a print and lifting it out of the sand revealed a sand dollar.

Sand dollars are related to sea stars, sea cucumbers, and also the sea urchin below.

At one part of the shore, there were so many sea urchins among the seaweeds that I had to walk really carefully so as not to step on any of them.

Among the seaweeds and seagrasses were also a few stranded jellyfish.

Most of them were dead, but the one above was still alive when I found it. Hopefully it could endure till the tides comes back!

They were many swimming anemones too.

These anemones can actually swim by pulsating its body and tentacles. The photo the left shows it tucking in its tentacles, while the right photo shows it pushing them out.

I almost stepped onto this beautiful shrimp which swam pass my feet. And it burrowed quickly into the sand when I tried to take a few photos of it.

Somehow, there were lots of moulting crustaceans too.

We saw a few crabs getting out of their old shells. In fact, even the hermit crabs were moulting!

Was not able to take a picture of it getting out of its old shell as it finished before I could take out my camera. Crabs and hermit crabs are most vulnerable when they just moulted, as their shell has not yet hardened. Anyway, here's how the hermit crab looks like when the shell has hardened and it was happily scampering around looking for food.

And the hermit crab was the only one looking for food. Remember the sand star we saw earlier? I found another one just beneath the sand, and turning it over revealed that it has been feasting on some button snails!

Tide was soon rising, and we had to move to the higher shore. And this was what we spotted there.

A ghost crab! Ghost crabs usually only come out of its burrow at night. They are also one of the fastest runners on the shores, being able to move about 100 bodylengths per second!

Sadly, just as we were leaving, we saw a few people coming to the shores holding plastic bags.

They are poachers...

Will there be a day when all our wonderful shorelife go extinct from over-collection?

Hopefully, one day the poachers will understand that we have very little natural heritage left, and leave our wild places the way they are...