Beyond the murky waters of Changi

This is a super delayed part two posting of a field trip on 24th June at Changi. I fell ill for a long time and therefore updates have been bare minimum.

If you can recall, I last talked about the proliferation of gorgeous sea fans at Changi. During that day, it was one of the three days of the year where the tide went to the lowest possible, also as known as the lowest water level mark for the intertidal zone. Beyond which is the subtidal zone that will never get exposed theoretically unless there are changes in barometric pressure during the super low tide or that there is a ..... tsunami kind of natural event.

Changi waters are known to be rather murky. Justin had took a brave act before to dive off Changi and the visibility is just bad. But the bad visibility doesn't mean that Changi is lifeless. Changi as we know is home to lots of unimaginable diversity of marine life. And we took the lowest ever possible tide to catch a glimpse of what lies beyond the murky waters of Changi.

Here's what one can find at Changi at a rare low tide.


At the rocky side of the shore, there are many of the Melted chocolate ascidians on top of the colourful sea fans which I talked about earlier in another post.


And I was amazed to find a jam packed area full of encrusting organisms at the rocky areas which includes ascidians, sponges and other stuffs. The only irritating thing in this photo is the stupid fishing line that fishermen litters to the shore.


Agnes found this pretty Blue-spotted flatworm (Pseudoceros indicus) which seems to like to feed on ascidians.


The sponges are very colourful and this one is in yellowish orange.


On and beneath rocks, one can definitely find the rock star or also known as the Crown sea star (Asterina coronata).

And that's not all, Changi is just too starry as more stars were found. Many of which were spotted by my star spotter... Siyang! So thankful that he was around to find the special stars. Here are the sea stars of the trip.


Biscuit sea stars (Gonodiscaster scaber) that do look like moulded biscuits.


Cake sea stars (Anthenea aspera) of different sizes and patterns.


And different colours as well. I just adore this bright orange cake sea star.


Of course Siyang found this special star, the Eight-armed sea star (Luidia maculata). In fact he found two. Though this particular one is small, they can grow up to huge sizes to a humungous arm length of 30cm.


And it was especially thrilling when Siyang found two of the Luidia sand stars which are probably Luidia hardwicki. I have never explored this part of Changi before and this is my first time seeing this rare sea star at this portion of Changi. The whole of Changi beach is just too long and there's just so much that we haven't explored properly.


It was quite cute to catch the moment of a big and small Painted Sand star (Astropecten sp.) getting together like a daddy and son. Though I don't know the sex of the stars :P


Not a true sea star, a feather star is its relative and it is just so stunning with many arms that look like feathers. Yes, it was spotted by the sharp-eyed Siyang again! :-)


A closeup of the pretty feathery structures of this featherstar.


A brittlestar is yet another star that is not a true blue sea star but they are also considered relatives under the Phylum Echinodermata. As their name suggests, they are quite brittle in nature and can break off their arms when in danger. Good thing is that God gave them the ability to regenerate broken arms.


Sea urchins are also echinoderms and they just look pricky. It's not the first time we see large masses of several Black sea urchins (Temnopleurus toreumaticus) coming together. I wonder what it is for.


Moving off from echinoderms, Siyang showed us his special find of many Spider crabs (Superfamily Majoidea) beneath a rock. They were performing an intertidal orchestra! Hear it at Agne's Journey of all sorts blog.


Encrusting on rocks are more life like this known to be tough Zebra coral (Oulastrea crispata) that we see even at the most beaten up shores.


Other fantastic finds that are as colourful as sea fans are the wide growth of hydroids (Class Hydrozoa).


And they can grow very abundantly on the pillars of any structures. But please do not touch them because you will definitely regret. That is because some of the hydroid species have stinging cells that inflict lots of pain if you have a brush with them.

Well, some stuffs or things in life are just better to be looked at than to be touched. :P


There were also a couple of snaily encounters like this handsome noble volute (Cymbiola nobilis).


And also this Tiger moon snail (Natica tigrina) that tends to be found at seagrassy and soft sediment substrates.


There were a lot of octopusy encounters that morning too! Everyone (almost?) loves octopus during a shore trip.


Unfortunately, some were stranded while others are trapped at tide pools during this super low tide.


Along the way, we saw this Common sea pen (Pteroides sp.). It has an orange foot that is usually buried. This poor creature could have been washed up.


In the murky waters beyond the lowest water mark, we could see many big sized Flowery sea pen (Family Veretillidae). The underwater life at Changi must be like a garden with these sea pens, hydroids and sea fans.

Last but not least, here are the anemones of the trip.


One of the biggest anemones in the north must be this Haddon's carpet anemones (Stichodactyla haddoni) that can be found in great numbers especially in Chek Jawa and Pulau Sekudu. While diving at Manado, I noticed this species of carpet anemone do harbour anemonefishes that probably are not recorded in Singapore waters.


More pretty anemones. The left is the Tiger anemone and the right is a Glass anemone (Doflenia sp.).


Though not a true anemone, peacock anemones (Order Ceriantharia) look just like, if not nicer than some true anemones. Interestingly, there is a Thorny sea cucumber (Colochirus quadrangularis) at the base of the peacock anemone.

It is nice to have a couple of lowest low tide of the year to catch a glimpse of marine life beyond the murky waters of Changi. Given that diving is nearly practically impossible in Johor Straits, what life is beyond the bad visibility will probably be up to our imagination. I am personally very optimistic after this particular trip.

More about that day's trip at Siyang's Urban Forest blog.