Thursday, May 19, 2011

Echinoderms of Pulau Sekudu on 19 May 2011

Just a quick listing of some of the echinoderms we saw today at Pulau Sekudu, an small island which is part of Check Jawa Wetlands, and hence is a protected area. You can only access the island with NParks' permission.

Lots of cake sea stars (Anthenea aspera) were seen today, though most of them were rather small - <5cm. They come in various colours and patterns, but my favourite is the orange ones.

The only big cake sea star saw was this one, which was more than 20cm wide.

Biscuit sea stars (Goniodiscaster scaber) were every where!

There was this rather huge one close to 20cm wide.

Sand stars (Astropecten sp.) were rather abundant too.

This sand star is more colourful than the previous one - not sure if they are just variations of the same species, or are different species.

We saw a few rock stars (Asterina coronata) too!

Only 2 huge knobbly sea stars (Protoreaster nodosus) were found. They used to be really abundant here...

The main surprise will be finding a good population of sand-sifting sea stars (Archaster typicus) here. Previously, I have only found one or two small ones. There were easily more than 30 mature ones here, and some of them getting ready for pseudo-copulation - the reproductive organs do not meet, but the males will stack on top of the female, and they will eventually release sperm and eggs together.

There are quite a few brittle stars, but most were hidden among rocks and crevices and hard to take photos, except this one.

I only found one feather star today.

There were quite a few pencil sea urchins (Prionocidaris sp.) though. Most of them were still rather small.

The Salmacis sea urchin (Salmacis sp.) was in season though, and there were hundreds of them. Most of them were in the coral rubble area, and had pieces of rocks and shells stuck to it. Some of the rocks even have little sea anemones growing on them!

Here's another Salmacis sea urchin with purple spines.

I saw 3 heart urchin test, but no live ones.

There were many little pink sand dollars (Peronella lesueuri)! Most of them not more than 2cm wide. The ones I saw during my previous trips were much bigger - about 5cm or more.

There were a few black sea cucumbers (Holothuria leucospilota) among the coral rubble too.

At the sandier areas, many sandfish sea cucumbers (Holothuria scabra) were seen.

Like most of our northern shores, the pink thorny sea cucumbers (Colochirus quadrangularis) were very abundant.

I found a white synaptid sea cucumber.

And several small little ones on a sponge.

This was possibly the weirdest scene I saw today - a ball sea cucumber (Phyllophorus sp.) stuck to a noble volute (Cymbiola nobilis)! What on earth are they doing???

Will put up another blog on the other animals were saw soon..

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