Back to the blue at Changi Beach

After close to 2 years, I am finally back to the intertidal zone!

The purpose for returning back to the blue was to continue with the sea cucumber research which I set aside 2 years ago. This project was highlighted during the recent Festival of Biodiversity organised by the National Parks Board.

The first stop was at Changi Beach Park, which has always been my favourite Singapore’s mainland intertidal spot because of the diversity of faunal life. I was with Ron and two of my colleagues.

The first creature we saw was the horned-eye ghost crab, Ocypode ceratophthalmus. This is a scavenger which is also known to be able to run very fast!

A live bivalve was attempting to burrow itself in the sane with much effort. It is interesting to observe its siphon which allows water to enter and exit its body for breathing and filter-feeding.

There were a lot prickly white sea urchin, Salmacis sp, scattered all over the beach. They camouflaged themselves by trapping pieces of shells, algae, and sea grasses cover their top.

This ribbon worm was extremely long, being close more a metre! It seems as that this relatively common worm still do not have a scientific name yet. Hopefully the Mega Marine Survey will eventually help to solve this mystery.

A nice find was this knobbly sea star, Protoreaster nodosus. This is still a little juvenile, and can grow up to more than twice its size eventually.

There were quite a number of these sea slugs, or more specifically, the geographic sea hare, Syphonota geographica. They are thought to grazed on sea weeds.

I also found two octopi, one hiding in the a dead fan shell and another in a huge bailer snail shell.

Moving on to the sea cucumbers, I was quite surprised to find so many Holothuria notabilis. They lie buried horizontally just beneath the sandy surface with their butt sticking out for breathing. Yes, they breathe through their butt!

Another burrowing sea cucumber is this. In her comprehensive marine wild fact sheets, Ria named it as the smooth sea cucumber. Based on some of its external characters, including their simple stubby tentacles, they can be safely placed in the genus of Paracaudina sp. Microscopic examination will be needed to further zoom in on its identity.

Another which deserves some study is this purplish sea cucumber which is frequently found under the rocks. I was unable to tell what it was at first glance; hopefully it will not elude me for long.

Meanwhile, at the other end of Changi Beach, Ria has found another fascinating sea cucumber which she highlighted in her blog. This is really interesting because it is very likely to be from a new family of cucumbers that is never recorded in Singapore!

Search for Pemphis acidula

After a failed attempt to search for the plant as stated above about a month back, KY, CK, WF, A and I were back again at the shore near Changi. This plant was first discovered by Ria and gang.

Trekking through the rustic grassland,

 
and reaching this small reservoir, which when high tide comes will probably connect to the sea.

There were some Rhizophora saplings in the reservoir.

 
These are the fruits of the sea lettuce (Scaevola taccada). All of them were bearing juicy white fruits.

 
Some other mangrove plants include the red flowered Lumnitzera littorea,

 
and the white flowered Lumnitzera racemosa.

 
Also in abundance is Bruguiera cylindrica (above), and Scyphiphora hydrophyllacea (picture not shown).

 
And of course, the highlight of the day, Pemphis acidula. This critically endangered plant is probably the only one individual left on mainland.

 
The flower, with very short stamens. It is insect-pollinated and not self-compatible. Hence, WF and CK were suspecting another plant is nearby since this is fruiting. But we were unable to locate it.

 
Here is the fruit. The seeds are covered by the brown capsule.

 
Here is how the seeds looked like. They fit together like a jigsaw puzzle.

 
And the seeds, when they are out. According to WF, they are dispersed by water.

 
I also managed to get some satisfying flower shots with my recently-repaired G11 and macro lens. This is the male flower of Buta-Buta (Excoecaria agallocha).

This it is the female cone of Casuarina equisetifolia.

 
This is the male cone~

Rain out at Changi Beach

Last Sunday, during another of my guided walks, I was cursed and blessed at the same time. Cursed because it had been raining (again) from 2am to about 6am. Blessed because 6am was the time when we started off with our guided walk.

I was glad to find a Horned Ghost Crab (Ocypode ceratophthalmus) after missing it the other time. They are scavengers and fierce predators at the same time, whereby it is known to pick off sea creatures, even baby turtles!

We found several Chitons crawling on an empty gong gong shell. These animals are protected by eight overlapping plates and this arrangement allowed them to curl into a ball when pried off the surface.

Here is a strange looking crab with very long antennae that I have never seen before. Could this be a kind of spider crab? Update: Just received info from CH that this is a masked burrowing crab (Family Corystidae). Budak also mentioned previously in his blog that the antennae were used to form a breathing tube when it is buried in the sand. Interesting new find for me!

I was glad to find the leopard sea cucumber (Holothuria ocellata) again. This burrowing cucumber have been recorded to be found at depths of 80m!

Under a long piece of plank, there was a big Swimming Crab (Family Portunidae) that had a broken claw. Fortunately, it can regenerate back the piece of limb after the next moulting.

Even though we did not manage to see the Sea Urchins again (sorry Mel), we were instead rewarded with another Echinoderm, the Cake Sea Star (Anthenea aspera)! This star is listed as vulnerable in our Singapore Red List.

Just as we were washing our feet, some anglers came by with a huge catch; an enormous stingray!

Though I forgot to take some pictures of my participants, I was lucky to get a snapshot of one of them at Changi Village where we had our breakfast.

Thanks to Sean for the photos of the chiton and sea cucumber.

Guided Walk at Changi Beach

Last Sunday, I brought a group of friends to Changi Beach for an intertidal walk.

We headed over to the jetty to see if the crab traps there had any crabs. Unfortunately, there were none but instead, the entire place were covered by thousands of creeper snails. These snails consists of an assemblage of different species of snails that feed on detritus.

We saw a few headlamps over the sea wall and I went over to ask a Malay guy who was using a small axe hammering on the rocks what they were doing. He was harvesting oysters on the rock and I borrowed one to show my participants.

Unfortunately, as the day broke, so did the clouds and it rained heavily.

We had to retreat to the shelters where we observed a huge maggot wiggling in the sand. Any help with this ID is appreciated. Update: As commented by Anonymous, "Actually the "maggot" is not a maggot but infact its known as June beetle larvae or sometimes to be known as a tree shrub which is a favourite snack for aboriginal people.Its known to contain high protein..."

Luckily, the rain dwindled soon after and we carried on with the planned walk.

The special find of the day is definitely the Seahorse. Mel found this creature gasping for air on the sand and we move it to a tidal pool to wait for the tide to rise.


There were lots of little Sand Dollars (Arachnoides placenta) shovelling half-buried through the sand.

This unknown sea cucumber which I termed as the leopard skinned sea cucumber has finally been identified as Holothuria ocellata. Thanks to Karenne and Dr Lane for forwarding my picture to various marine experts in this field. A clearer picture can be found in my earlier Changi posting.

Here is another unknown sea cucumber. Obviously, there are still many marine life left to be studied in Singapore.


Another related animal that we saw was this big Biscuit Star, (Goniodiscaster scaber). All of them belonged to the same group, the Echinoderms otherwise known as the spiny skinned animals.

This Flower Crab (Portunus pelagicus) seemed like a master of camouflage with seaweeds and barnacles growing over it.

There were also many hermit crabs that have anemones on their shells. It is said that some of them actively harvest these stinging animals to prevent predation from octopuses.

A larger species of hermit crab, the Orange Stripped Hermit Crab (Clibanarius infraspinatus) resided in the shell of the Spiral Melongena.


Lastly, a juvenile Noble Volute (Cymbiola nobilis). This is a predatory snail with a nice shell patterned with mountain ridges.

This is my first time organising my own proper guided walk and it turned out to be pretty successful. Looking forward to more in the future.

Thanks to Sean for using his photos for this post.

Nocturnal Changi

Today I decided to go the end of Changi Beach for a short predawn intertidal trip. Glad to have the company of Diana and also getting a free ride to and fro from her.

The first creature we saw was a Horned Ghost Crab (Ocypode ceratophthalmus) that seemed to be have one disabled eye.

Another common crustaceans was the Moon Crab (Ashtoret lunaris). These rounded crabs have eight paddle legs, allowing them to slice with ease into the sand for a quick concealment.

The Bladder Moon Snails (Polinices didyma) were all active at this unearthly hour searching for it’s next meal.

I was glad to see a Thorny Sea Cucumber (Colochirus quadrangularis) extending it’s feeding tentacles like a blooming flower.

This leopard-skin sea cucumber is very abundant on the shore; we saw at least 20 of them! It’s a pity that an ID have not been placed on it yet. Update: This cucumber has been identified as Holothuria ocellata, possibly a new record in Singapore (though it had been spotted frequently prior to this).

I found this dead flower crab which was already surrounded by it’s scavengers, the Dog Whelks (Nassarius sp.). They can apparently very sensitive to dead matter through the use of their long siphon.

The Sand Stars (Astropecten sp.) is another echinoderm very common on the shore probably due to the abundance of button shells which they are known to feed on.

Some Slipper Limpets (Crepidula sp.) occupied a Noble Volute shell together with an Orange Stripped Hermit Crab (Clibanarius infraspinatus).

White short spine sea urchins (Salmacis sp.) littered the seagrass habitat, grazing on the vegetative cover.

We were also excited to see several big prawns crawling about the sandy floor.

There was also an sea anemone that was detached and floating aimlessly in the water.

Sand dollars (Arachnoides placenta) feed on tiny detritus and animals found in the sand.

True to its name, the File Fish (Possibly Chaetodermis penicilligerus) have a rough skin that can give a nasty cut as I experienced when I tried to released one from a trap.

Lastly, a live troughshell, Mactra mera with a tiny bit of siphon sticking out.