Discovery @ Frog Island on 20 July 2008

70th Discovery Posting:

Frog Island otherwise known as Pulau Sekudu (first time going there) was our destination for the morning (our boat was leaving at 430am from the jetty, so it meant another climbing out of my bed in the wee hours of the morning...)

You might wonder/ask why is this place known as Frog Island? Look at the picture below to get an idea.
This is probably because there is a large boulder on the island which is in the shape of a frog. And someone has even added eyes to the boulder to aid in your imagination along... hahaha

Well, for a second fact, this island is actually located within Singapore waters. Here's a map which I got from the internet to give everyone a better idea where the island is (picture below). '+' marks the spot.
Side note:
Map retrieved from http://sg.pagenation.com/sin/Pulau%20Sekudu_103.9878_1.4048.map

As you can see, Pulau Sekudu is an island near Pulau Ubin and it is also located very near to Chek Jawa, one could possibly say there is the crown jewel of Pulau Ubin.

By the way, there is no jetty on this island, so we had to climb a ladder off the boat once we reached the island. Another first for me. =P

Well, there's also a urban legend/story which tells us why Pulau Sekudu is also known as Frog Island.

The story goes like this (a short version),
Long before your time, 3 animals, an elephant, a pig and a frog lined up along the coast of Changi in a swimming race from Changi to Johor.
As they raced, the frog drown halfway through the race (I'm still wondering why, as I feel frogs should be better swimmers compared to elephants and pigs) and thus formed Pulau Sekudu.
Well, the elephant and pig didn't complete the race as well, in fact they drown a little further up from the frog drown, and so the two animals formed the island of Pulau Ubin.

Anyways, first 'discovery' is something which is really big in numbers (for me) on that island, peacock anemone (pictures below). I counted about 50 of them before I gave up counting...
Discovery Note:
1. To see their full beauty, you will need to see them in a certain depth of water, like above.
2. The long small things around the ring of the anemone are actually tentacles, and there are two types of tentacles, one on the outer ring while the other on the inner ring.
3. The tentacles on the outer ring gathers food (plankton) are called the marginal tentacles and the tentacles on the inner ring (which are usually shorter) are called oral tentacles is for manipulating food into its mouth located in the center.
4. Their 'home' is a tube found below the mouth area, therefore they are also known as tube anemones.
5. Click here to read more about them.

Second 'discovery' is a fish which I have never seen before. Thanks to CH, I finally know what this fish is. This is most likely to be a long tail tripod fish (picture below).
Discovery Note:
1. As I observed the fish going around me, probably finding food amongst the seagrass and seaweed, it was swimming in a very strange matter.
2. I could say that it swim with one side of its body during most of the time as I was looking at it.
3. Is this a playing dead act by the fish cause it thinks that I may be a predator?

Third 'discovery' is a nudibranch which I've never seen before. This possibly might be a Discodoris lilacina (picture below).Discovery Note:
1. Nudibranch means naked gills. They are also sea slugs but not all sea slugs are nudibranchs.
2. They are often very colourful/attractive, a warning sign in the natural world. Telling predators that eat me if you dare, cause you might die trying to do so or after you have done so.
3. Some nudibranchs have other forms defences for survival. For example: some nudibranchs feed on things which have stinging cells and they somehow store these stinging cells on themselves also, thus when the nudibranch can release the stinging cells when being threaten.

Fourth 'discovery' is also a first sighting for me, an orange rock star (picture below)!Discovery Note:
1. The rock stars I've seen are usually brownish in colour, like the colour of rocks, probably for camouflage purposes.
2. Thus to find an orange individual is considered a uncommon sight (for me, that is).

Well, of course, we couldn't miss the 'die-die' can see attraction of this island, the frog rock with eyes and even a smiley face (picture below). =PFinally, it's thanks to RY for organising this trip for us and everyone who made this trip another fun-filled trip. =)

Extra:
Read RY's aka Tidechaser's blog posting for other marine creatures we saw during this trip.

Discovery @ Cyrene Reef on 8 July 2008

Sixty Ninth Discovery Posting:

Along our major shipping lanes, ringed by Jurong Island and Pulau Bukom (where you can find many petrol chemical plants), there lies a haven hidden by the waters, appearing only when the tides are low enough. Can you see it (picture below)?
As this haven is not connected to any land, the only way to get there is to make an amphibious landing, this calls for a small boat and physically getting wet (part of the fun going for shore trips =P ) (picture below)
Why do I call Cyrene Reef a haven?
Because studies from Star Trackers show that Cyrene is probably the only reef in Singapore where juvenile Knobblies are commonly seen. And probably also the home to "the only sustainable population of Knobbly sea stars".

Side Note:
a) Star Trackers does monitoring body growth, survivorship, habitat utilization and movement patterns of knobbly seastar (Protoreaster nodosus) individuals at marine habitats in Singapore.
b) And the 'star troopers' running this project is primarily CK and SJ
c) Their blog address is http://startrackers.blogspot.com/

As I explored the reef, I 'discovered' 27 individuals of the Knobbly sea star, below are pictures for some of them. Enjoy~ =)

This was my favourite star of the day (picture below)You might wonder how big are the juveniles of the knobbly sea star, here's a scale of two with my hand (picture below). Do remember they can grow to as big as your face!Seeing so many knobbly sea stars really left me star studded. Besides that, knowing a place such as Cyrene Reef exists reminded me once again that our waters although murky, it is rich in marine life! And it will continue to be if we all take care of them one way or another.

Ways can include:
a) putting your rubbish where they belong (in the rubbish bins or recycle bins), not littering/dumping into our waters,
b) leaving marine life at their homes (don't collect marine life nor shells, cause the empty sea shells may be potential homes for hermit crabs).
c) You can also learn more about them to understand their value in our environment, and probably share this knowledge with your family/friends or possibly even volunteer/blog for our shores!
d) And speak for our shores if possible, because marine life don't speak our language. =)

Very soon, we had to leave Cyrene the way we came (picture below). And looking at our busy shipping ports nearby, (with expansion going on nearby Cyrene Reef) (picture below), I marvel at how Cyrene can be so starry. Probably all the strict rules for ships is one factor?Finally, would like to thank Ria for arranging this trip and all who came. =)

Extra:
a) Read the entry on wildfilms about this trip to Cyrene.
b) Read more about Cyrene Reef here.

Semakau Inter-Tidal walk on 6 July 2008

Sixty Eighth Discovery Posting:

This posting is a second part of the weekend trip to Semakau for inter-tidal walks.

On Sunday (6 July), I guided a group of mudskippers, couldn't ask them to skip for the group shot at the seagrass lagoon as I didn't want to create too much damage to the habitat =P (picture below).
Now, our first 'discovery' is a gigantic carpet anemone, which isn't really gigantic, gigantic is just its part of its species name if I'm not wrong (picture below).
Discovery Note:
1. For self defence and preying purposes, they have stinging cells in their tentacles which will release or 'shoot' small 'needles' when upon contact. So I won't really advise you to touch them although our skin might be 'thicker' than most marine creatures. This is to prevent you from getting stung.
2. They lack an anus, so they split out any indigestible food through its mouth.

Although there weren't as much nudibranches as we saw compared to Sat (5 July), we did see a couple of flatworms, here's one of them (picture below). Discovery Note:
1. Flatworms are hermaphrodites, which means a flatworm has both the male and female sex organs.
2. And some species of flatworms engage in penis fencing, in which two individuals fight, trying to pierce the skin of the other with their penises; the first to succeed inseminates the other, which must then carry and nourish the eggs.

Our hunter seekers also found a sea horse (picture below). Third 'discovery'! Discovery Note:
1. They are hard to find as they are well-camouflaged.
2. Do you know that a seahorse is actually a fish? Yes, it is, but instead of having scales, they have an inflexible armour of overlapping bony plates.
3. A seahorse cannot swim faster because it doesn't have tail fin and pelvic fins like other fishes, thus it is well-camouflaged. But they can make a short burst of speed if in danger.
4. They may look harmless, but they are actually quite voracious predators. It sits in wait and ambushes on any tiny animals that drifts or wander by.
5. They have a very simple digestive system (no stomach) thus they need to eat almost constantly. Baby sea horses are known to eat thousands of tiny shrimps in a day!
6. And of course, the most well-known fact of the sea horse is that the male can get 'pregnant', this is because the female seahorses lay eggs in the pouch of a male seahorse and it is in their where the eggs will be fertilized and then the male seahorse will carry them till the eggs hatch.
7. Want to read more about the sea horse, click here to read it from the online Chek Jawa guidebook.

Our hunter seekers (RY and SY) also found the 'star' of the walk, thus here's a group photo with it. No skipping as we didn't want to leave any more damage to the shore (picture below). =P
Fourth 'discovery' has got to be a find, as this is my first time seeing this crab, possibly a smooth spooner (picture below).Discovery Note:
1. This crab which we saw was a huge one, as it was about 25cm (across).
2. The tip of the pincers of this crab is spoon shaped, thus it's name is as such.
3. The structure of it allows this crab to scape algae off the rocks to eat.

So that's it for the weekend trip over at Semakau. Thanks to all mudskippers for coming and everyone else who came! =)

Extra:
a) Read tidechaser's entry on this weekend's trip to Semakau.
b) Check out Urban Forest too for an account on the same trips.

Semakau Inter-Tidal walk on 5 July 2008

Sixty Seventh Discovery Posting:

Over the mornings of the past weekend, I was over at Semakau land-fill island for another weekend of inter-tidal walks. And on Sat (5 July), I was guiding the group, Noble Volutes.

And the first 'discovery' of the morning was a group of common sea stars (picture below).
Discovery Note:
1. Their tube feet are interesting as they are used for walking, handle food as well as breathing, and probably to catch prey as well, talk about multi purpose!
2. Sea stars get stressed when out of water, this is because while we have blood circulating our bodies, they have sea water circulating their bodies.
3. They are not as common as their name suggests. This is due to past over-collection and habitat lost past and present. So don't take them away from their homes when you see them. =)
4. Some sea stars are predators that prey on worms, crustaceans and bivalves while some are known to eat decayed plant matters.
5. Many sea stars eat with their stomach outside their body. When doing this, their tube feet will pull the two shells of a bivalve apart. And while still attached to their prey’s body, they extend their stomach out through their mouths into the bivalve shell.

As the sunrise was really nice, I decided to take a Volute group photo with the sunrise as the background (picture below).

And very soon, Volutes got to meet one of their own kind, and it was laying eggs! Second 'discovery' (picture below)!

Discovery Note:
1. Volutes are carnivorous.
2. They prey on bivalves, enveloping the victim completely with their foot forcing the bivalve to finally open from exhaustion and lack of oxygen.
3. They can grow to more than 20cm and used to be common but now threaten due to 'harvesting' from humans and habitat lost.

Not far away, the third 'discovery', Volutes got to see another kind of sea snail laying eggs, a spiral melongena (picture below).
Discovery Note:
1. They seem to like to lay eggs on hard surfaces.
2. Each "petal" is one egg capsule.

It was also kinda of like a sea slug day, as we saw a few types of nudibranches, here's one kind which is not so commonly seen at Semakau, a platydoris nudibranch (Platydoris scabra), fourth 'discovery' (picture below).
Discovery Note:
1. 'Nudibranch' means 'naked gills'. The name comes from the flower-like gills found on the back of many nudibranchs. These nudibranchs use the gills to breathe.
2. Nudibranchs are related to snails. Little baby nudibranchs are born with shells, but they lose them when they become adults.
3. Most nudibranchs are carnivores, they eat immobile or small, slow-moving prey. Examples are sponges, ascidians, hard corals, soft corals, sea anemones etc. This particular nudibranch feeds on sponges if my memory serves me correct.

Fifth 'discovery' were two different kinds of mushroom corals (pictures below). Discovery Note:
1. Most mushroom corals do not form colonies like most other corals and some mushroom coral is usually made up of a single polyp (The ones shown above probably are).
2. Unlike most corals, most mushroom corals are attached to the reef/rocks only when they are small.
3. As larger individuals, they will detach themselves from the reef/rocks (if they had attached themselves to the reef) and live loose on the seafloor.

And just almost next to the mushroom corals, we spotted a sandfish sea cucumber or also known as garlic bread sea cucumber, sixth 'discovery' (picture below).

Discovery Note:
1. The popular Chinese name for sea cucumber is haishen, which means, roughly, ginseng of the sea.
2. They have a soft, wormlike body and can range from a few centimeters to even 90 centimeters in length!
3. To repel predators or when stressed, a sea cucumber might expel their innards or ‘vomit’. And if too much of their innards are expelled, they might die off as a result.
4. This particular species of sea cucumber is commonly harvested for food for the Chinese, but this has to properly processed before any consumption, as it is mildly poisonous.

And the star highlight of the walks would have to be the knobbly sea star, our hunter seekers (HW and LK) found us two today (picture below)! Btw, this is the seventh 'discovery'. Discovery Note:
1. They get their name from the knobs they have.
2. Although most of them are mostly red or orange in colour, beige or brown coloured knobbly sea stars have been spotted before also.
3. I have heard that they feed on lots of different things, I wonder if anyone knows what's their actual diet? A good topic for study probably, haha =P
4. Can you believe that a knobbly seastar might be larger than your face? It’s about 30cm across! (look at the picture below to get an idea)

Of course, a traditional group shot with the stars (a pun here probably?). And the last but not least eighth 'discovery', a sea urchin (picture below)! Discovery Note:
1. Upon first look, you might think that a sea urchin is sessile (incapable of moving), but this is not so, they actually use all the pointed tips to move around.
2. The pointed tips are actually spines connected to their skeletons.
3. Some sea urchins have venomous spines, so just to play safe, it is advised not to come into contact with the spines of any sea urchins.
4. The orange dot which you can see (picture above) is actually is anus, it's mouth (claw-like) is located on its underside.
5. Sea urchins belong to the same phylum of animals as the sea stars and sea cucumber, so they have no brains!
6. Their diet consists of plant and animal matter, including kelp, decaying matter, algae, dead fishes, sponges, mussels, and barnacles.
7. Click here to read more about sea urchins on the Chek Jawa guidebook, which is available online.

Finally, a look at the beautiful corals on Semakau (picture below). Thanks to all Volutes who made this trip another enjoyable trip despite I having to wake up around 330am in the morning =P.