10 January 2012

Day of Snails at Cyrene with Shell volunteers

Back on Cyrene with yet another enthusiastic team from Shell and NParks!
And today, we saw some special snails, thanks to our sharp eyed visitors! Including the Fig snail!

The first snail we find is the Black lipped conch (Strombus urceus). While other snails creep slowly on a broad foot, this snail hops! It sticks its knife-like 'door' attached to a muscular foot into the sand and uses it like a pole-vaulter. It has large eyes, probably because it has to see where it is going.
Like yesterday, we also saw many Grey bonnet snails (Phalium glaucum) today. This one buried in the sand was eating a Cake sand dollar (Arachnoides placenta).
Most of the Bonnet snails we saw were buried, only one was cruising above ground. We saw more of these snails yesterday.
Vivek found my favourite Find of the Day!
It's a Fig snail (Ficus variegata)! I rarely see this snail and it's the first time I've seen it on Cyrene. Even though I've been visiting this shore so many times for a long while.
Here's what the snail looks like when we put it in some water. So far, we've only seen this snail in Changi and Changi East, while Liana spotted it at East Coast Park. It is not confirmed what they feed on. But there are suggestions that they eat sea urchins and other echninoderms, though there have been no actual observations of them doing so.
Another special mollusc: the visitors also spotted this octopus. I've never seen one with such large 'eyes'. Are they real eyes or just spots that look like eyes? Wow!
A slug, which is also a mollusc! The Leaf slug (Elysia ornata) does indeed look like seaweed and is often overlooked! Some Elysia slugs are solar powered! They suck the juices out of seaweeds but don't digest the algae's chloroplasts (the part that contains chlorophyll). These chloroplasts continue to carry out photosynthesis inside the slug and provide the slug with extra nutrients.
We also saw other exciting stuff. Azlin found a large Filefish (Family Monacanthidae) that was just drifting along pretending to be a leaf.
Nearby, was a pair of Synaptid sea cucumbers in two different colours! They are often mistaken for worms!
We revisited the Carpet anemones (Stichodactyla haddoni) with its pair of anemone shrimps (Periclimenes brevicarpalis) that we saw yesterday. This is mama shrimp who is larger and has larger and more white spots.
This innocuous looking bunch of polyps are zoanthids or colonial anemones (Order Zoanthidea). They can contain palytoxin which is among the most potent natural marine toxins. So it's important not to touch unfamiliar marine life.
We then hurry over to the reef edge where large Knobbly sea stars (Protoreaster nodosus) can often be seen in large numbers.
I couldn't resist taking an underwater shot of a white Knobbly sea star.
We also saw a purple flowery soft coral (Family Nephtheidae) with a large long black sea cucumber (Holothuria leucospilota) hiding under it.
As we were looking at the soft coral, a huge long scary worm slithered out of the rock crevice! It's the Giant reefworm which has the lovely scientific name of Eunice aphroditois.
Nearby was a Giant carpet anemone (Stichodactyla gigantea). These anemones usual host Clown anemonefishes. But today, I couldn't find any in this one.
On the rocky area, we saw our final special snail of the day: the Giant top shell snail (Trochus niloticus) which is now rarely seen on our shores.
Other snaily sightings included many sand collars laid by moon snails, and an Oval moon snail (Polinices mammila). We also saw other interesting animals including Common sea stars (Archaster typicus), White sea urchins (Salmacis sp), Flower crabs (Portunus pelagicus), a hairy crab (Family Pilumnidae). Also of course, lots of seagrasses and various kinds of seaweeds.

Unlike yesterday, we enjoyed a cool and dry day. But just as the sun was about to set, the weather finally caught up with us. In pelting rain, we hurried back to the safety of the big boat. The dinghy is already waiting for us on shore.
Here's the first batch making it back in high waves in the rain. Behind them, a huge container ship making its way past Pasir Panjang Container Terminals. Cyrene lies in the middle of the industrial triangle and yet it has amazing marine life!
Although soaked to the skin, everyone was in high spirits and stayed out on the windy bow on the way home! We had a safe trip as usual, thanks to Alex and his crew of Summit Marine.
Thanks to Azlin from NParks for organising the series of trips. And to the wonderful team of from Shell and NParks for finding so many interesting animals and putting up with my very lame jokes! It's been great for me to have a chance to share one of my favourite shores with so many people!

More about Cyrene Reef.

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