Friday, May 29, 2009

First public intertidal walk at St. John's island

Today was our first public intertidal walk to St. John's island. And boy, it was really quite an opening with many first-time sightings for me. Both Henrietta and I were guiding a group from the National University of Singapore Society.

We headed to the sandy lagoon where we saw several animals feeding.

The first was this worm, probably a ribbon worm that was spotted by my participants. Can you see that it was actually entangling itself on a prawn?

The poor animal was struggling frantically. Unfortunately, the worm had a stronger grip and it eventually swallowed the prawn whole. You can actually see its mouth opening to engulf it!

The second animal which caught my attention was this snail. I know that it was a whelk from its long flexible siphon which is used as chemosensory organ. But I was confused seeing a sickle shape structure sticking out, just like the trapdoor or operculum of a conch. However, closer examination revealed that it was actually the big pincer of a male fiddler crab! SK, our molluscs expert commented that this olive whelk (Nassarius olivaceus) was probably just feeding off a dropped off pincer.

The next discovery was found by our hunter seeker, RH. The beautiful animal here is a sundial snail (Architectonica perspectiva). This uncommon snail is listed as Endangered in our Singapore's Red Data book. Thus, it was heartening to see it laying egg masses today, meaning that we might be seeing little baby sundials in the near future? You might want to see KS's blog for more information about this animal.

Another first time is this little pebble crab (Leucosia sp.). True to its name, it's exoskeleton looks just like a piece of rock allowing it to blend into its surroundings.

Here is the dear friend of Sponge Bob; Patrick the starfish. Even though the common seastar (Archaster typicus) normally comes with 5 arms, it is not uncommon to find some with less. However, when I was telling my participants that this resembled the ninja's shuriken and flipped my chopsticks to make it more descriptive; droplets of mud from my sticks flew and splattered over one of them. Oh dear, if you happen to read this post, my sincere apologises again!

We saw several land hermit crabs (Coenobita cavipes) at the rocky cliff. These crabs although found near the shore, can drown if they are submerged in the water.

Here is a pretty fireband murex snail (Chicoreus torrefactus). They feed by secreting acid to soften the shell of a molluscs and drilling a hole through it using their radula before sucking out the insides.

A fine though scorching hot day at St. John's, thanks to many of my keen eyed and enthusiastic participants.

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