Tuesday, May 24, 2011

Changi Beach- Just so much to discover!

Changi Beach has hidden its gems and secrets beneath the murky waters. But once the tides gave way during a super low spring tide, a huge pasture of seagrass and seaweed meadow that is full of life will be revealed!

I love visiting Changi during predawn trips for various reasons. One of which will be the spectacular sunrise which creates a lovely backdrop to soak in the beauty of nature.

What's so different on this trip, as compared to previous trips, would be the large numbers of Pink sand dollars (Peronella lesueuri).

They were only thought to be found at Pulau Sekudu. It was after the oil spill in May 2010 that we started seeing these charismatic echinoderms appear slowly on this shore. Was there something in this habitat that has changed since then, thus allowing for the proliferation of these pink sand dollars?

I always like to begin the blog post on a happy and starry note. Thanks to Mei Lin and Ria, three baby Knobbly sea stars (Protoreaster nodosus) were found! This one is almost completely green, which may be because of the fact that such coloration helps the juvenile stars to camouflage among the seagrass nursery.

Another similar looking knobbly baby was found later on, which we thought to be the same as the previous one. However if you look at the centre, this one has an orange dot and the previous one does not have.

Ria later also found another knobbly sea star. This one is slightly bigger and has developed their knobs and possesses the usual reddish coloration that the adults have. I am always fascinated how does the colour change as these baby green stars grow up.

More stars on the shore includes plenty of juvenile Biscuit sea stars (Goniodiscaster scaber) and a couple of Cake sea stars (Anthenea aspera).

In addition to the above list of sea star species, there is also the Plain sand stars (Astropecten sp.) as you can identify with on the bottom right photo of the above collage of various sea stars found.

I was looking for the Thorny sea urchins (Prionocidaris sp.) which can be found on the shore and the team found two of them.

There were quite a number of sea cucumber finds, too many to blog about but one of the more special ones would be this Remarkable sea cucumber (Holothuria notabilis).

This transparent-looking sea cucumber is named as the See-through sea cucumber (Paracaudina australis).

On top of being rich in echinoderms, there are also many sea anemones found on Changi.

I was heartened to see for the first time so many adult sized Haddon's carpet anemones (Stichodactyla haddoni) on this mainland shore.

Some of them have a pair of pretty Five-spot anemone shrimps (Periclimenes brevicarpalis)!

Moving on to crabs, here are an assortment of different types of crabs sighted during the trip.

Among which, this feisty red swimming crab caught my attention. It was rather fierce! The colour indeed matches its temper.

Ivan's wish for the box crab was fulfilled when we saw this Spotted box crab (Calappa philgarius) on the high shore.

Ria pointed out to us several of these cute little Mangrove whiprays (Himantura walga) swimming about in the shallow tide pools.

It's the first time I came across the Ornate leaf slug (Elysia ornata) at Changi shore! Probably the first record too? These slugs are more commonly found on our reefs among the southern waters of Singapore.

A huge slug would be this uncommon orange-brown Spotted sea hare (Aplysia oculifera). Two of these were spotted. Please do not disturb these fellows as they can release a purple dye as a sign of distress.

James found this Bumpy-faced armina nudibranch (Armina sp.) that feeds on the many sea pencils on this shore.

So where is the bumpy face in this nudi? The shield-shaped oral veil or the "face" has finger-like bumps that make this slug look like they have bushy moustaches. Haha!

The last series of animals to feature in this creature-packed post would be the molluscs- gastropods and bivalves. In simpler terms- snails and clams.

There were many special mollusc find such as this large Baler volute (Melo melo) found by Ria! I posted a comment on Facebook with this photo. The caption goes like this: Bailer snail of Changi shore says "Please don't bail me out from my home".

That's not all! Not only did we found one but THREE of these rare snail. Wow. This juvenile individual was spotted by myself among the seagrasses.

I also found the third Bailer snail. It's such a treat and surprise that I see none of the more common Noble Volutes on this trip but three of these rare snails.

At first I thought this was just a normal moon snail. But after showing Ria some photos of this snail from different angles and judging from the fact that it is impossible for the mantle to fully retract into the shell, I then realized this is the Naked moon snail (Sinum sp.) which I have not seen before. :)

Ria found yet another special snail. This is the Japanese bonnet snail (Semicassis bisulcatum) Their shell has a shape that is typical of a helmet. Thus we sometimes also call this the helmet snail.

The sole of the mantle of this snail is purplish black- a very different colour from the previous photo from the top.

James found a special bivalve which has a rather obscene scientific name, Verpa penis. This Watering Pot shell (Verpa penis) is named as such because of its long shape and that they are perforated with tiny holes at the broad end.

How do we know if this is a bivalve? Just look closer on the tiny pair of bumps which are all that is left of the 'valves'. It is not too obvious in this photo.

As I begin the post with an early sunrise, here's the end of the post with a higher sunrise shining its rays onto the beautiful shore. And for those who are viewing this the first time, you can't imagine this is Singapore right? ;)

More photos with lots of other creatures of the trip here: http://www.flickr.com/photos/koksheng/archives/date-taken/2011/05/20/


Ria Tan said...

Thanks for these lovely sightings! Love the 'face' of the Melo melo! And the Sinum is our best shot of this curious sluggy snail!

Vee said...

Hey! I was just passing through and I saw your awesome pictures of marine life at Changi. Realised that you were an NUS student too, life sciences I presume? I'm going Changi Beach soon to do a recce for a brochure project and I've noticed the low tides are at mad timings. So I would like your opinion if I were to go at a time where the tide was slightly higher, say 0.7, would I still be able to see stuff there, and if so, how deep would I have to go to see marine creatures?? Or would I have better luck if I were to go at night like 1900??(:

Unknown said...

hi there, would you like to leave your email address with me, we can discuss this further.

sherlock said...

hi, nice pics! never know changi beach have so much marine life. I am an nus student and I am making a poster for a mod on singapore biodiversity, can I use some of the pictures you have here?

Unknown said...

Hi sure no problem. But pls acknowledge my full name. Thanks.

Chris Wong said...

Hi Mr Kok,

Truly enjoy your blog. Cool photos.

I'm going to Changi Beach on 11/5/16 since the tide is 0.1 meter high. Which part of Changi Beach do I visit?


Unknown said...

Hello Chris, most stretches of Changi can be visited during low tide. So feel free to just go ahead and explore

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