Cowries Galore!

There were ominous flashes in the sky as we were about to depart for Pulau Sekudu at 1am. The NEA rain map was quickly consulted. It showed huge red spots in the South that looked like they were heading towards Ubin. With much discussion about the South-West moonsoon, and how rain should deposit over the land mass and thus be depleted by the time clouds got to the East, we made our way to Changi. Through pouring rain. Not good.

But the sky was clear over Changi and we headed determinedly for our favourite shore.

As always, Sekudu seldom disappoints. It was crawling with cowries! We've never seen so many of these delightful snails before.

More familiar to most people as dead shells with the distinctive 'teeth' at the opening, these animals when alive are far more fascinating than their shells alone. A living cowrie envelopes its shell with a part of its body called the mantle. The mantle prevents algae and encrusting animals from settling on the shell. The mantle also continously lays down new shiny shell material. This is why cowrie shells are so shiny and pretty. So much so that they were used as currency in some island communities in the past. The cowries above are commonly seen on most of our shores.

The Miliaris cowrie (Cypraea miliaris) is less commonly seen. It is usually seen in pairs and indeed, several were seen close to one another. The pretty spotted shell is usually covered with a mantle that has fleshy projections. This camouflages the snail very well indeed!

The fabulous Onyx cowrie (Cypraea onyx) is also seldom seen except at such undisturbed shores as Pulau Sekudu. It has a golden brown shell with a handsome black-and-white mantle with tiny projections.

Both the Miliaris and Onyx cowries are listed among Singapore's threatened animals. Half of the cowrie species of Singapore have be wiped out due to habitat loss.

Of course, with Chay Hoon, Ron and HP around, there are bound to be lots of slugs and nudibranchs to be found. And usually TINY ones. Sigh.

Fortunately, today, the nudibranch they found were less of a strain to back and eye.

The very cute Cerberilla nudibranch (Cerberilla sp.) has lots of projections on its back. These contain special sacs that store the stinging cells of its sea anemone prey. The stinging cells remain undischarged and now protect the nudibranch instead!

Indeed, when alarmed, the little animal turns itself into a ball of stinging tentacles! The nudibranch is a burrower (as we discovered).

It seemed also the season for Jorunna nudibranchs (Jorunna funebris). These delightful polka-dotted nudibranchs are sometimes seen on our shores, and particularly common on Sekudu. It is believed that they eat blue sponges. That may indeed be so, as this nudibranch looks like it just finished laying its rosette of eggs next to the blue sponge (the white blob on the left of the sponge).

This pair of nudibranchs looked like they were about to do so something about laying eggs before they got left high and dry as the tide went out.

The mess of nudis on the left looks like another pair that probably were further along into making new nudibranchs before they got stranded. When in the water, the nudibranch looks a lot prettier, with a fluffy set of gills on its back, and black tipped rhinophores at the head.

I saw this strange blue nudibranch. I still don't know what it is. It's the first time I've seen something like it.

There's so much we have yet to discover about our shores!

Of course, there were lots of other sightings. We were joined by some adventurous folks: Tiong Chin, Alan, Evelyn, Albert and friends. Who came despite the early hour and forbidding weather on the mainland. They were excitedly talking non-stop since we landed, exclamations of findings ringing throughout the night. Alas, the tide was short today and we had to leave even before the sun rose.