Feb 22, 2008

Slow on Sentosa

For many people this is their idea of a seashore...
White artificial sand and rocks, waters free of irksome creatures, a nice civilised picnic.

Ivan and I, however, headed out for the Real Thing. It was a slow if not very low tide, and we just wanted a leisurely shore trip.
Although fronted by industrial installations of Jurong, and right next to major coastal works, this natural stretch of Sentosa is full of life!

It has a scattering of hard corals, including this lovely large and luscious Mussid coral (Family Mussidae) aka brain coral.
And this pretty Disk coral (Turbinaria sp.) which was edged in pink.Among the corals was this little white fan worm that looks like it had a perm.We also came across a little Mosaic crab (Lophozozymus pictor) which is very poisonous but so pretty.On the way back, as the tide was coming in, we explored the higher shore. Ivan and I realise there are probably TWO different kinds of Turban snails (Family Turbinidae)!
They have a different texture on the smooth rounded 'door' (called operculum) that seals the shell opening.

The one we always see and know as the Dwarf turban snail (Turbo bruneus), has a smooth operculum.The other one has a different texture on the operculum.Could this be Turbo intercostalis instead? Hmm ...

The upperside of the two snails are also slightly different.T. bruneus has finer cords, while the other one has rougher cords on the shell.

I also saw this strange Nerite snail. I'm still not sure what it is.The operculum on the underside is not pimply like the usual nerites that we see.I wonder what kind of nerite this is?!

As the tide came in and night fell, the mudskippers were also out and about. Like this little Gold-spotted mudskipper (Periophthalmus chrysospilos).It's much easier to photograph these creatures at night.

Ivan really wanted to see an octopus. And when we got to the rubbly parts, indeed, he spotted one! Bravo!And just as we decided to go home, Ivan spotted several Land hermit crabs (Coenobita cavipes)! I've never seen these crabs yet on this shore. While the smaller ones on the sand refused to come out of their shells, we discovered one right on the rocks, busy checking out the crevices for titbits for dinner.

Wow, it's amazing what we can learn and see from a shore, no matter how many times we visit it.

Alas, today, we noticed a greyish layer on some parts of the shore.The greyish stuff penetrates quite deep into the sand.But it didn't smell like something artificial or bad. It looks like fine silt and wasn't sticky or gooey (No, I didn't taste it to find out what it was). The ground was also rather soft and silty for Sentosa, which is usually very sandy with very clear waters.

Could this be something to do with the dredging and work on Labrador which is just opposite this Sentosa shore?

We'll just have to keep visiting the shores to check up on them on a regular basis.


YC said...

oh wow! land hermies! ive never even seen one before!

i didnt know and never really looked at the turban snails too - in retrospect it shouldnt be suprising that there were two species. the more you look the more you find out theres more to find out heh.

great job! so many great finds!

Snail said...

The nerite is Nerita polita, the polished nerite, I think. IIRC, it's the only one with that sculpture on its operculum.

ria said...

Thanks Snail! That's great to know!

I don't see this nerite often. Only once at St. John's, also among lots of small stones on a very rocky shore and nearer the high water mark.


Snail said...

No worries!

They pop up in a variety of habitats. On some beaches in NE Queensland, they burrow in the sand at high tide and emerge when the water recedes. Then they climb rocks to feed. But elsewhere, they live among small rocks and coral rubble. They must be quite adaptable!