23 December 2010

Strange sea slug on Sentosa

This small and well camouflaged slug looks just like the pink encrustations found on the long Tape seagrasses on Sentosa! It has two pairs of 'tentacles' so it's probably a Seagrass seahare.
While the Seagrass seahares (Phyllaplysia sp.) I've seen so far have stripes, this one has pink patches!

The natural shores of Sentosa were bleak and quiet today. The explosion of blooming Hairy green seaweed (Bryopsis sp.) that I saw on our trip last month is over. The shore is now rather bare of seaweeds. There were few animals too, and the water seemed murkier than usual.

But without distractions, I was forced to take a really close look at common things. A cluster of pretty Polished nerites (Nerita polita) ! They come in a wide variety of shell patterns! There are many different kinds of nerites and snails on the rocky shore.
Like these Neomeris sp. seaweeds. Each green-white 'sausage' is actually made up of fine spirals emerging from a central stalk, much like a compact bottle brush. I didn't realise the central stalk is transparent!
A cluster of very tiny seaweeds in the shape of daisies! I think these are Parvocaulis parvulus and I often see them growing among Neomeris.
The seagrasses on the shore were doing alright. With nice carpets of fresh green Spoon seagrass (Halophila ovalis) and many clumps of Tape seagrass (Enhalus acoroides) , their leaf blades still long and unbroken.
But I saw many clumps of Feathery seaweeds (Caulerpa taxifolia) that were losing their green colour. I'm not sure what is happening here.
I saw a few Frilly anemones (Phymanthus sp.) . Russel saw a Giant carpet anemone (Stichodactyla gigantea).
There were still many different kinds of colourful sponges on the shore. Although the sponges were generally small and well dispersed on the shore.
These Chocolate sponges (Spheciospongia cf. vagabunda) are, as usual, homes to tiny brittle stars. But the sponges were much smaller than usual.
This shore was suffering quite badly from coral bleaching when we visited in June. Today, I saw some hard corals including several big colonies. They were unbleached and very brown. In fact, it was only looking closely at their corallites that I realised that they were different kinds. From left to right: Pore hard coral (Porites sp.), Cyphastrea sp. with tiny ring-shaped corallites, and probably another kind of Favid coral (Family Faviidae) with hexagonal corallites.
And here, a Favid coral with a maze-like pattern, and two Goniopora corals (Goniopora sp.) with small corallites. I feel that I saw very much fewer hard corals today. I also saw a few small colonies. Hopefully this means the shore is recovering?
There were several clumps of this feathery soft coral, but in all of the colonies, the polyps were retracted. Oh dear. I wonder why. Sadly, I didn't see any leathery soft corals (Family Alcyoniidae) large or small. But Rene saw some!
I saw many small swimming crabs (Family Portunidae) zooming around. But I only saw one Red egg crab (Atergatis integerrimus) and I didn't see any Hairy crabs (Family Pilumnidae). On the high shore, there were also fewer Land hermit crabs (Coenobita sp.).
As night fell, I managed to attempt a shaky clip of a little octopus foraging!

On our way to the main reef, I noticed several bunches of Sargassum seaweed washed ashore, each with hard coral (often still living) attached to the end of the seaweed. Oh dear.
There are several interesting plants growing on the natural cliffs. Among them, the Critically Endangered Nyireh mangrove trees (Xylocarpus rhumphii) on the shore are looking well! The leaves are all green and fresh. But no signs of flowering or fruiting. On my previous trip here, I was rather alarmed to see the leaves had turned orange. But Dr John Yong assured me this was a normal seasonal happening for this kind of tree.
The Critically Endangered Critically Endangered Delek air (Memecylon edule) on the shore was fruiting! This tree is famous on Chek Jawa.
There are nice low bunches of the very handsome Raffles' pitcher plant (Nepenthes rafflesiana) here. The pitchers are modified leaves and contain a substance that can dissolve hapless insects that slip and fall into the pitcher.
The pitcher plants were blooming and fruiting!
During our trip, a small group of students were also exploring the shore. It's great to see people learning more about our marine life!
This evening, some photographers made the trek to the shore with all their gear, apparently to take sunset shots. How nice!
The sunset is dramatic and apocalyptic especially over the massive refineries on Pulau Bukom which is just opposite Sentosa.
The natural shores of Sentosa have suffered not only from coral bleaching in 2010, but are also close to the massive reclamation project at Pasir Panjang Container Terminal. Other ongoing works nearby include dredging near Cyrene Reef, building of the boardwalk at Berlayar Creek.

And now, there's going to be a Crane Dance show at Resorts World Sentosa which will spew pyrotechnics into the water every night.

Let's hope this last natural shore on Sentosa can survive and recover.

More about this trip by
  • Russel on facebook with gorgeous photos and on his blog
  • Rene on facebook with crabs, leathery soft coral and more!

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