17 August 2012

Bountiful Buttons at East Coast Park

The Button snails still plentiful on a stretch of East Coast that was badly hit by the oil spill in May 2010.
There's lots of empty shells on the high shore, and the sandy shores lower down were teeming with them. Although the tide wasn't very low, we managed to see quite a lot of marine life here, on this artificial shore.


Button snails (Umbonium vestiarum) are really cute! They have little blue eyes on stalks, a furry thing between the eyes (I'm not too sure what it is), and a little tubular siphon to breathe through while they are buried.
Button snails have a long leaf-like foot, fringed with tentacles. They can use their foot to flip themselves over, and to leap. A good ability to have when trying to escape burrowing predators.
Tiny Button snails escaping from a large burrowing predator make frantic little trails.
The main predators of Button snails on this shore appear to be Olive snail (Family Olividae) and Ball moon snails (Polinices didyma). We came across many sign of tunneling predators, with lots of Button snails in their wake.
The moon snail looks like this when bulldozing through wet sand. There's a little flap that possibly allows the snail to suck in freshly oxygenated water while it burrows.
We arrived a little early so while we waited for the tide to go out, we had a look at the artificial seawalls. The artificial rocks today are coated in a nice layer of all kinds of seaweeds. All kinds of creatures big and small were busy among these marine meadows.
There were many tiny Periwinkle snails (Family Littorinidae) out and about. I have no idea what this 'pile up' of Periwinkles is about.
There were also lots of tiny crabs and also Javan limpets (Siphonaria javanica). Further up the nearby canal, the walls were coated with oysters and other encrusting bivalves.
Predators on the seawalls include lots of Drill snails (Family Muricidae). There seems to be various kinds of them.
There were several Sally-lightfoot crabs (Grapsus albolineatus) and of course, lots of Purple climbing crab (Metopograpsus sp.).
As the tide fell, we  had a quick look around the sandy shore. In the shallow water, there were many Moon crabs (Family Matutidae), lots of Flower crabs (Portunus pelagicus) and I saw two Charybdis annulata swimming crabs with rings on their legs, one with living barnacles on its body.
There were also many Tidal hermit crabs (Diogenes sp.) and small Striped hermit crabs (Clibanarius infraspinatus).
Other animals on the sandy shore included one Smooth sea cucumber, one Painted sand star (Astropecten sp.) and many Cake sand dollars (Arachnoides placenta) , most were small or medium sized.
Here's some tracks left by Cake sand dollars. Signs of other creatures on the sandy shore include some Acorn worms (Class Enteropneusta) and Sand bubbler crabs (Scopimera sp.).
We also saw several kinds of sea anemones. Chay Hoon found many burrowing in the sand, and I came across some intriguing ones on the sea wall. These have yet to be identified, there's so much more to learn about our shores.
I came across a tiny patch of Needle seagrasses (Halodule sp.)! Wow. My first time seeing this on this shore. These seagrasses are pioneers and are among the first to settle on bare sand. Hopefully, they will lay down the foundations for other seagrasses and more marine life to settle on this shore.
But beneath the clean sand is a layer of dark sand. Signs of the oil spill?
Here's a photo of the crude oil I saw landing on this stretch of East Coast shore on 26 May. I've not been able to visit this shore as often as other Tanah Merah shores, visiting it only in July 2010 and May 2011 as well as a year ago in Aug 2011. Ivan also visited on 22 Apr 2011 (facebook).
This shore looks pretty much like it used to before the oil spill. Although the tide wasn't very low so I couldn't check out the lower shores.

Today is the start of the last series of super low morning tides for the year. Our last chance to check out some of our favourite shores when they're at their liveliest!

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