12 December 2008

Semakau in the rain

A less visited corner of Semakau was explored on another wet trip yesterday, with the intrepid Semakau Book team.On this trip were Eric (the book's Photographer) and Marcus (the book's Writer) and Kok Sheng, Mei Lin and Samuel to help find things and take photos as well.

This somewhat more rocky stretch is crawling with colourful Nerite snails (Family Neritidae) in various colours and patterns. These snails are identified by the structures on their undersides.A look suggests that they are the aptly-named Chameleon nerites (Nerita chamaeleon).Kok Sheng found several of these non-descript but special sea stars, see his blog for lots more photos. The Cryptic sea star (Crypasterina sp.) has so far only been seen on Pulau Semakau. These secretive stars are unfortunately listed as 'Vulnerable' on the Red List of our threatened animals.Here and there among the small stones, a little jet of water would spout out in regular intervals. These little 'fountains' were made by octopuses hiding in their holes. An octopus that is stressed tends to be white in colour. These poor animals were probably anxiously waiting for the tide to return.Among the stones, I came across this sea cucumber that also looked stressed as it was spitting out white stuff from one end.Here's a closer look at the sea cucumber. I'm not too sure what kind of sea cucumber it is as it doesn't resemble any of those we've seen regularly on our shores. It doesn't look much like the Pink-spotted sea cucumber which is found on our Southern shores. It looks more like the Beige sea cucumber that we sometimes see among the seagrasses of our Northern shores. We have yet to find out the identifies of both these sea cucumbers.

Before we could do much more, it started to pour with lots of lightning all around. Sean as usual showed lots of concern for us by sending smses. Thanks Sean! We huddled under shelter during the worst of it. Fortunately the weather and lightning eased up quite soon and we went back to exploring in the drizzle.
I really wanted to find some mud lobster mounds and tramped off among the mangroves. Alas, no large mud lobster mounds where I went, but I did see this promising pile of large clumps of fresh mud.Mud lobsters (Thalassina sp.) play a critical role in sustaining a diverse variety of plants and animals in the back mangroves. Without them, the mangroves are much poorer. These humble but important creatures are listed as 'Endangered' on the Red List of our threatened animals.As I stumbled in the rain in the mangroves, I came across this strange mangrove tree. It had very nice knee roots.But with leaves that I've not seen on a large mangrove tree. Here are its flowers.And a propagule high up in the tree. Is this tree Ceriops tagal? Hmm...
The seaward side of the mangroves were nice and sandy. With seagrasses growing among the aerial roots of the mangrove trees!Zoanthids, large sea anemones, sponges and other reef creatures were also seen among the aerial roots! I also noticed that some of the aerial roots had 'roots' branching out along the surface of the sediments. I had a quick look at the sandy strip between the mangroves and the reefs. It was reminiscent of a shore in the North, with all the seagrass species seen on Semakau except for Noodle seagrass (Syringodium isoestifolium) represented there. There were lots of Common sea stars (Archaster typicus) including many small sized stars, Gong-gong (Strombus canarium) and the Black lipped conch (Strombus urceus), as well as Window-pane shells (Placuna sp.) and young Fan shells (Pinna sp.).And this small Tailed sea slug (Philinopsis sp.). Some species of tailed sea slugs eat bubble shell snails, hunting them by following their slime trail then swallowing them whole.

There were patches of coral rubble and rocks closer to the reef edge and here were nestled all kinds of sponges and other encrusting organisms.
Both the Giant carpet anemone (Stichodactyla gigantea), photo on the left, and Haddon's carpet anemone (Stichodactyla haddoni), photo on the right, were seen. But I didn't see any animals living in the sea anemones, unlike Kok Sheng who saw a baby 'Nemo'!
And in a pool, I saw this little carpet anemone. Could it be Stichodactyla tapetum? Hmmm...

All too soon the sun started to set, and the not so low tide turned so we headed for the long long walk back to the jetty.I noticed that snails are rather aimless in their wanderings. And some snails create different kinds of trails. Are the straight trails of snails in a 'hurry' to get some place, and the more ruffled trails of feeding snails? Or do these show the different ways snails move on sand? Or is it something to do with the sand? There's lots still to find out about our shores!

Sadly, this corner of Semakau is where huge oil rigs are parked for maintenance and repairs, as well as it appears, some large ships.
The little roofed structure on the right is probably the fish farm that is located there as well.

The boat that took us to Semakau made a little detour to drop off this well dressed young man on one of the ships parked in our harbour.This is real Delivery in action! Actually, the real purpose of the work boats we take is to service such ships as well as the industrial installations on our Southern Islands. We are the ones on the odd journey and not these working people.

Well, another field trip later today and every day until Monday!

More blogs about this trip


  1. Yes, the tree is Ceriops tagal. Nice close-up of the flowers.

  2. Thanks for the ID! It was a beautiful tree!



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