Jul 31, 2007

More Sea Anemones of Changi

We're back again with the Anemone Team on a different stretch of Changi to check out the sea anemones that live in softer ground.

And what wondrous anemones there were! At first glance, they seemed alike. But Dr Daphne points out the differences and a closer look reveals their delicate beauty.

We saw lots of these sea anemones with a pair of maroon dots near the mouth. These are the largest of the sea anemones found on the soft shores of Changi.

And also lots of these sea anemones with a pattern of radiating lines from the mouth and white bars on the tentacles.These are not as large and can be quite small (about 2-3cm across).

Very similar to the previous is another sea anemone with white bars AND dark parallel lines along the tentacles and without the radiating lines around the mouth.These are also common, and not very large.

The anemones all look very different inside and underneath. Dr Daphne will take a closer look and figure out what they really are.

Throughout our trips, Dr Daphne has been trying to match our observations with a much earlier work done on Singapore's sea anemones. It's a hard job as many of our shores have changed since then. On Changi, there has been repeated 'beach improvement', which wiped out the biodiversity. It's nice that life has returned but still, a pity that we keep losing it every time someone feels Singaporeans should have white sand instead of mucky soft silt, which the animals prefer.

We were constantly misled throughout the trip, by the feeding tentacles of the buried Ball sea cucumber (Phyllophorus sp.)This fat rotund animal lies completely buried and only sticks out its feathery tentacles to feed. It was really nice to see so many of them on Changi as there were mass deaths of these animals on Chek Jawa during the massive flooding earlier this year.

We were not as easily confused by the Peacock anemones (Order Ceriantharia) which were very numerous on this stretch of Changi.The inner ring of shorter tentacles easily distinguish these from true sea anemones. But it's sometimes hard to see this in murky waters, so there were a few false alarms.

We trudged slowly to the seawall where MORE surprises were in store. I never really took a close look at the brown blobs that cling so tenaciously to the cracks, crevices and surfaces of the wall.

Dr Daphne, however, shows us just how nice they really are.

Here is a bigger one, with banded tentacles and a nice pattern around the mouth.And there were lots of tiny ones with an entirely different pattern.
Again, she'll have to take a closer look to figure out what they are.

Changi was very much alive this full-moon morning. There were several large and busy sand stars (Astropecten sp.)
The soft shore was also literally crawling with lots of brittle stars!This particular kind seems to purposely turn upside down, showing its pink parts. We don't really know why.

There are not many hard areas on this shore, so a little stone is hot property for snails in serious need of egg-laying locations. These melogena snails were really hard at work laying circles of yellow egg capsules.
Another encounter with a pair of Moon crabs that look like they are about to mate. I forgot to ask Swee Hee about it as he was far away. But must really find out more about this as I've seen it so often and haven't a clue of what's going on.
At a more grassy area, I came across this cuttlefish! It was holding up a pair of its arms, not sure why. It pulsed through a series of pattern changes before gliding off into the murk.
Changi is indeed special and rich with all kinds of marine life. And more so when we take the time and effort to look closely.

Tomorrow, ANOTHER trip, this time to my favourite Southern Island. I'm sure we'll find lots of interesting sea anemones and learn more about them from Dr Daphne.

Jul 30, 2007

Sea anemones of Changi

Another early morning trip with the Sea Anemone Team. We're back on Changi!

Dr Daphne is reassured to see the large Haddon's carpet anemones (Stichodactyla haddoni), some of them with anemone shrimps!We also saw several of the much smaller Stichodactyla tapetum. We had always thought they were merely baby carpet anemones. Dr Daphne says they are in fact a separate species!They can be quite tiny, a little bigger than a seagrass leaf. And don't grow much bigger than the length of about 4-5 seagrass leaves across.

We also saw more of the 'strawberry' sea anemone (because it looks like a strawberry when its tentacles are tucked into its body column). This one was expanded. It has a pair of maroon spots near the mouth, not so obvious in this photo. Dr Daphne is already familiar with this sea anemone and we leave them alone.

Among the first-time encounters was this large plain sea anemone without any markings.Dr Daphne thinks it might be similar to one that we saw at Sisters Island a few mornings ago. But she'll have to have a closer look.

We are also eager to show Dr Daphne the sea anemones found on the shells of hermit crabs. It is only on Changi that I've noticed that lots of hermit crabs have sea anemones on their shells. There are usually lots of hermit crabs. Alas, today, we could only find this one large hermit crab, with a small sea anemone on it.

Dr Daphne shared that one of her colleagues observed in a tank that when an octopus was introduced into the tank, all the hermit crabs soon transferred sea anemones onto their shells. Without the octopus, the hermit crabs left the sea anemones alone.

When a hermit crab changes to a new shell, it may also transfer the sea anemones to the new shell.

Dr Daphne was also very interested in the tiny sea anemones found on whelk snails (Family Nassaridae). Whelks are scavenging snails with long 'noses' to 'sniff' out the recent dead. They can move quite fast once they get a whiff of a delectable carcass.

Many of the whelks on Changi had a tiny hitchhiking sea anemones on their shell. The sea anemone can be quite large compared to the size of the snail. It has pretty stripes.
I wondered how the sea anemone could 'find' the snail, and certainly the snail can't 'put on' a sea anemone the way a hermit crab does. The snail doesn't have pincers. Dr Daphne says this is one of the wonders of nature, that tiny sea anemone larvae can settle onto the correct place in order to grow up into a mature sea anemone. Often, the larvae are attracted to the snail by the chemicals that the snail produces.

Chay Hoon also found a brown blob (no photo, sorry). When we took a closer look at it out of the sand, it was very strange indeed! Dr Daphne is intrigued and will take a closer look at it in the lab.

We also saw lots and lots of Peachia sp. and left them all alone. Having properly looked for sea anemones, we now realise these sea anemones are quite common indeed.

And finally, after many back-breaking attempts to find them, Yu Chen finds the tiny seagrass anemones!
They are really tiny and he literally crawls on the sand to find them! Way to go YC!

Other sea anemone facts we learned today: Chay Hoon went diving at Hantu yesterday (immediately after the sea anemone hunt, she's amazing), and saw what looked like a sea anemone on a sea whip. We all thought she was mistaken, but Dr Daphne says this is quite possible!

We also wondered whether any sea anemones were parasites. Dr Daphne says the seagrass anemones above can be considered parasites. As larvae, they eat up the gonads (reproductive organs) of jellyfishes. When the jellyfish swims over seagrasses, the larvae drop off and settle on the seagrass and turn into adult sea anemones. Gross!

This stretch of Changi is very rich. There were lots of busy moon snails, which have smooth white bodies much larger than their shells. These white blobs were often mistaken for sea anemone blobs! To the frustration of the Anemone Hunters.

Among the seagrasses was also this rather large scallop.And another commonly encountered animal on this shore, the cuttlefish.There were also lots of moon crabs, including this pair that looked like they were up to making baby crabs.Another satisfying Anemone Hunt. And good weather too. We are convinced it is Dr Daphne that is holding the wet weather at bay.

Let's hope our luck holds for the trip tomorrow!

Jul 29, 2007

Sea anemones of Sekudu

Another early morning trip with Dr Daphne and the Sea Anemone Team, and wildfilms who abandoned filming for the Anemone Hunt. Again we (vainly) promised NOT to look at Other Lifeforms.

As soon as we landed, we came across these little tentacly creatures.There were lots of them, but Dr Daphne points out that they are NOT sea anemones and are instead Peacock anemones (Order Cerintharia). Cerianthids have an inner ring of shorter tentacles.

There were also some of the usual larger Peacock anemones (photo on the right) where the inner ring of shorter tentacles are more obvious.
We also saw lots of Swimming anemones (Family Boloceroididae) (photo on the left). These anemones are basically a ball of tentacles. You can see the little mouth in the centre of this one.

Dr Daphne told us that these swimming anemones can drop off their tentacles on purpose if they are scared. AND each tentacle can eventually regenerate into a complete new swimming anemone! But NOT ALL sea anemones can do this. In fact, very few can.

We also saw lots of Haddon's carpet anemones (Stichodactyla haddoni).There are identified by their very rounded tentacles that pack together closely on the surface, and by the unique pattern of long-short tentacles at the edge of the oral disk. Tiny transparent shrimp are often found on this sea anemone, often many shrimps on one sea anemone.

But THESE are the sea anemones we came for at Pulau Sekudu.Dr Daphne will take a closer look at them and let us know what they are. I've seen them in large numbers at Sekudu, in smaller numbers on Chek Jawa, and recently on the Sentosa shore that has since been buried under reclamation.

We also looked closely at the large boulders on the island and Dr Daphne found these blobs rather interesting.They were nestled among the mats of tiny clams that form a 'nest' with the byssus threads that they produce. Wow! Let's wait and see what they are.

We tried very hard to find the tiny green sea anemones that Dr Daphne found on seagrasses on Changi. But alas, failed to find any. They are probably really hard to spot.

As we walked, I asked Dr Daphne which came first, the sea anemones or the other tentacly cnidarians like corals? She believes while the first cnidarians were probably something like the modern sea anemone, the sea anemones that we have today are probably more like a solitary hard coral polyp without its skeleton.

In fact, she said, there had been a study where scientists reduced the calcium content of the water in a tank of hard corals. They found that the hard corals stopped producing a skeleton and also stopped their colonial growth and became more solitary. And when they raised the calcium content in the water, the corals reverted to a more colonial growth and resumed producing a skeleton! She also said studies suggest our hard corals today produce 80% less calcium in their skeletons than in the past.

It's just amazing what you can learn just by walking with Dr Daphne. She's such a great teacher.

We wandered off to the rather hard area where we seldom go, as we are usually distracted by the richer seagrass areas.
This area is full of zoanthids or colonial anemones. NOT true sea anemones, these animals can produce toxic substances.

Dr Daphne shared a story of how an aquarium keeper foolishly tried to get rid of zoanthids growing on a rock in his tank. He poured boiling water on the rock and inhaled the resulting steam. He landed up in hospital!! Another good reason NOT to keep a home aquarium?

Although we promised not to look at other animals, we couldn't help but notice the large numbers of white sea urchins among the seaweeds.The sea urchins have a habit of carrying things over themselves, like little shells, bits of dead coral and rubbish. Dr Daphne shared that the bodies of these sea urchin comprise of crystals that some how allow light to penetrate into the body. So they carry things as a kind of umbrella to protect themselves from the sunlight!

I also came across an intact skeleton of a dead heart urchin.
This relative of the sea urchin is an echinoderm, like sea stars. You can see the five part structure of the body in the five-petalled pattern where the tube feet of this animal emerges. The heart urchin is a burrowing animal and is rarely seen above ground. In fact I've only seen the living animal once. When alive, it is covered with spines, like a sea urchin.

Apparently the rest of the wildfilms crew also saw other stuff including their favourite slugs, even though they tried hard to only look for sea anemones. Ron shares more about the trip on his tidechaser blog.

Again, Changi seems much richer in sea anemones that Chek Jawa and Pulau Sekudu. Wow, who would imagine that?! Tomorrow, we'll be checking out Changi and I'm sure we'll see and learn more about the sea anemones there.

Jul 28, 2007

Sea anemones of Sisters Island

The moon was full, if rather hazy and the crazy Sea Anemone Team were out once again. This time, we bring Dr Daphne, world expert on sea anemones, to Sisters Island.

I confessed to her that we rarely look at sea anemones at Sisters because it's just teeming with all kinds of other marine life. So it was a rather refreshing look at one of our favourite shores, with an Anemone-Only Hunt and a promise to ignore All Other Lifeforms.

Shortly we soon found lots of the frilly sea anemones (Phymanthus sp.) that Dr Daphne wanted to have a look at. Although they are VERY common on our shores, we know virtually nothing about them.

Dr Daphne wants to confirm whether those that look different are indeed different. One of the Phymanthus species is named after Singapore! Phymanthus singaporeansis. She says if she can't really find any difference, they might all be OUR Singapore Sea Anemone! Ron has more photos and stories about the hunt for frilly sea anemones on his tidechaser blog

And as we hunted for these rather well camouflaged and generally well embedded frilly sea anemones, we came across a lovely large Merten's carpet anemone (Stichodactyla mertensii).

How delightful! It was home to False clown anemonefishes (Amphiprion ocellaris)! There was one big mama fish and two small fishes. Those are not her babies, but unrelated anemonefishes that settled into the sea anemone. These fishes can change gender. The biggest fish is the female, and the next biggest the mature male. Should the female die, the male will change into a female and the next largest fish take his place as the mature male!

Dr Daphne checks the sea anemone carefully to be sure it isn't Stichodactyla gigantea (which we haven't been able to see yet in our trips). She confirms it is NOT S. gigantea. It is indeed Stichodactyla mertensii because it has those large colourful bumps on the underside of the anemone. (The next day, Dr Daphne tells me she thought further about this anemone and she thinks it IS Stichodactyla gigantea. Because the bumps were NOT that colourful, because the tentacles were moving (even the parts without the fishes), because the oral disk was wavy and not flattened out, and because it was found in coral rubble and not among living corals).
The mama clown anemonefish is quite tame and undisturbed by our explorations.

Dr Daphne was reassured to see these wonderful fishes. She was surprised that there were no anemonefishes on the large anemones at Chek Jawa. I shared that we thought they were not there because the water wasn't salty enough at Chek Jawa. She thinks not. She thinks they have all been removed in the past. She says it's hard for new ones to settle if there isn't a source of these fishes nearby. How sad.

She tells us that these fishes can live for 20-30-40 years. As a result, the anemones that shelter them must live for at least 100 years or more! So we leave fishes and anemone alone, as they should be.

Sadly, these fishes and anemones are taken from the wild for the aquarium trade. These usually soon die either enroute or in the tank, as it is difficult for artificial habitats to mimic what nature provides. Dr Daphne says this is particularly tragic because in an aquarium, the anemonefishes don't need sea anemones for protection.

The other sad thing that Dr Daphne highlighted, is that many aquarium keepers think sea anemones reproduce by dividing. They sometimes even purposely divide these large long-lived sea anemones. She stressed that in fact, MOST sea anemone DO NOT. Certainly the large sea anemones don't, and when so divided will soon die. Most sea anemones have sex and don't reproduce asexually.

We also seriously hunt for the "NOT the Condylactis" sea anemone, and Ron finds one! They attempt to have a closer look at it but alas, the equipment lets them down. More on the tidechaser blog (Ron: it's called a Yabby Pump).

Dr Daphne also spots lots of other marine life, including this beautiful flatworm, possibly Pseudobiceros sp.
As the tide started to come in, we headed to the high shore. Along the way, I just can't help but see the teeming non-anemone residents (although we were supposed to focus on the blobs).

The Sisters lagoon is teeming with the Blue-spotted fantail ray (Taeniura lymma). Not only are there many of them, but they are often also half hidden in the sand. It's important to really watch your step.
There were lots of strange fishes that I've rarely seen and haven't a clue what they are.
And this cute little filefish (Family Monacanthidae) with a very bristley area near the tail.
Sisters Island is also just crawling with octopuses. YC shot this one in action! As it foraged, it rapidly changed colours and patterns.
As the tide rushed back in, we thought that's it, no more nems. But then, we start spotting sea anemones on the sandy area!

Dr Daphne says this one is a Peachia sp, distinguished by the five bumps in the middle of the mouth and the 16 tentacles in a single row. I've also seen this on sandy areas in our Northern shores like Changi.
When the Anemone Team digs one up to take a closer look, they are amazed at just how long it is! On the left are what we see of the anemones. It's tough to find them as they're small and well, just blobs. But its no problem for Eagle-Eyed Chay Hoon and the rest of the team.

We also spot an odd blob.Which squirted water like a watering can, when we took a closer look at it. A behaviour similar to the one we found on Changi (see Kok Sheng's wonderful creations blog). And we weren't squeezing it or anything. Dr Daphne will have to take a look at it in the lab to identify it.

Meanwhile, Dr Daphne has found a blob which looks different from the other blobs we've found. All in all, a most exhilarating day of discoveries!

On Wednesday, Dr Daphne visited St. John's Island at high tide and she found FOUR new records of sea anemones! One of them was quite high on the shore where most people probably wouldn't look for anemones.

She also shared that from just the brief trips she's had so far, she can easily confirm 15 sea anemone species for Singapore! There are more that she needs to look at more closely before she can be sure what they are.

Wow! Aren't our shores just amazing?!

Tomorrow, another shore to show Dr Daphne, and more to learn from her about our sea anemones!

See also other blogs about this trip for other stuff I missed.
The tidechaser blog spider conch, synaptid sea cucumber, brittle star, moon crab.
The budak blog a much more eloquent account of the trip

Jul 19, 2007

Hantu: anemone or not?

The Sea Anemone Team and wildfilms were back out on the shore early this morning. This time we go to Pulau Hantu for a look at sea anemones in a reef habitat.

As soon as we arrive, we start hunting for those tentacly blobs that we've come to know better over the past few days.

Dr Daphne is particularly keen to find Edwardsia hantuensis that was described from a specimen from Pulau Hantu and thus named after Hantu. It's a tiny blob like thing similar to what Yuchen found yesterday at Chek Jawa.

Yuchen as usual, is the most enthusiastic and is really having a close look at the shore for this elusive little anemone.
We also learn along the way, what is NOT a true sea anemone.

Compared to the habitats at Changi and Chek Jawa that we visited the last two days, there are more anemone look-alikes in a reef habitat. To confound the first time anemone-hunter.

True sea anemones belong to Order Actiniaria.

This is sometimes called the Anemone coral (Goniopora sp.). It is a hard coral (Order Scelerectinia) with a hard skeleton. The polyps that make up this colony have long bodies with little tentacles at the tips. The skeleton is often hidden when the polyps are extended. This is a leathery soft coral (Order Alcyonacea), also a colony of tiny polyps with long bodies and little tentacles at the tips. They are embedded in a shared leathery tissue instead of a hard skeleton.
These blobs are corallimorphs (Order Corallimorphoria) and are NOT true anemones, although they do look very much like them.These are colonial anemones (Order Zoantharia). These clusters of little animals with long bodies and short tentacles may be connected to one another through underground 'roots'.Earlier on, during our Changi visits, we also learn that Peacock or Tube anemones (Order Ceriantharia) are also NOT true sea anemones.

So what are true anemones?!

This frilly looking animal is a true anemone called Phymanthus sp.
There's two of them in the photo above. They come in a wide range of colours and patterns and Dr Daphne is quite interested in finding out more about them.

Here's some of the variations I've seen in the past, from old photos. We saw some of these variations on Pulau Hantu today.Dr Daphne is quite keen to study the ones we saw on Pulau Hantu. It appears, although these sea anemones are VERY common, they have yet to be studied thoroughly!

These sea anemones are firmly embedded in coral rubble so they are very hard to get a closer look at. Fortunately, with the help of the indefatigable Trixie and Ivy, Dr Daphne manages to get a few. Swee Hee lends a manly hand with some of the more difficult situations.

Dr Daphne is also VERY interested in this little star-like anemone with very few arms.
These anemones are very shy and disappear instantly at the slightest trace of danger. I rarely see them. So we were lucky that Marcus, Liana and Yuchen were with us to help find FOUR today!

Here is some of the variations I've seen in the past.I used to call them Condylactis sp. but Dr Daphne thinks they might be something else altogether. I can't wait to find out more about them from her!

On our Northern shores (Changi, Chek Jawa), the common large carpet anemones are Stichodactyla haddoni. On our Southern shores such as Hantu, Stichodactyla mertensii is more common.
These humungous animals are easily identified by their brightly coloured undersides with pink or red spots, and long skinny tentacles arranged in rows. So there's no need to take a closer look at these sea anemones in the lab.Often, a pair of anemone shrimps may live in these large sea anemones. Anemone fishes are also commonly seen in these sea anemones, but we didn't see any today.

We also looked closely at seagrasses to try to find more of the teeny sea anemones that settle on the leaves. The few suspicious clumps I could see with my feeble eyes turned out to just be other blobs.

Dr Daphne earlier told me that these seagrass sea anemones actually hitch a ride on jellyfishes. When the jellyfish wanders over seagrasses, the sea anemones drop off and settle on the seagrass. While travelling, these sea anemones settle on and eat the jellyfish's gonads! (Gonads are a big word for reproductive organs). Life on the shores never ceases to amaze me!

Alas, although we combed the soft shore a second time on the way back to the boat, we failed to find the Edwardsia hantuensis.

Throughout the trip, dark clouds gathered and rolled towards the mainland. Here hovering over the petrochemical plants on Pulau Bukom, just metres off from the reefs where we were.On the opposite side of this ominous landscape, the sky was bright and blue!
But still, in the distance, dredging of some sort is going on near the reefs.
Our reefs on Hantu are rich with marine life that are interesting even to world renown scientists.

Let's hope developments around the island spare this amazing natural and national treasure of ours.

More stories and photos about the Sea Anemone Team on the budak blog

Anemone Workshop, 21 Jul 07
Dr Daphne later gave a workshop about sea anemones in general and the sea anemones we saw in particular. Here's some blogs about the workshop...
wonderful creations blog by Kok Sheng
habitatnews blog by Siva