It wasn't really a low tide, but low enough to explore the splendid Sisters shores.I stayed mostly on the high shore, and for the first time, saw the Haddon's carpet anemone still submerged.
With a pair of resident anemone shrimps (Periclimenes brevicarpalis) happily wandering about on their host home.Even on the high shore, I came across six clumps of Acropora hard corals (Acropora sp.)!
Each clump had at least one of these intriguing clams tucked among the branches.
I still have no idea what these are.
I've seen these little hairy crabs with blue eyes before on Acropora hard corals. But only had some clue after the Red Data Book on Singapore's threatened animals was published. Is this the Hairy coral crab (Cymo andreossyi) which is unfortunately listed as 'Vulnerable'. It is an obligate symbiont (i.e., only found on) Acropora and Pocillopora hard corals. It belongs to the Family Xanthidae.
There were lots of other corals too, including this glow-in-the-dark coral!
Some corals become luminescent at sunset! Here's more about why this happens.
Not all fuzzy things among the coral rubble are rubbishy stones. The octopus is a master of camouflage and this one blended perfectly with its surroundings. Betraying its presence only by slight ripples in the water.
Sisters is one of the few places where we can be almost certain to encounter the very pretty Head-stripe goby (Amblygobious stethophthalmus), generally only found near good reefs.There were plenty of Perchlets (Family Chandidae) everywhere, and a few blue flashes of Silversides (Family Antherinidae).
And this fish that I don't know.
I saw the Burrowing snake-eel (Pisodonophis crancrivorous) again. And this one stayed so still, I could take close-ups of its head.
As well as its sharp pointed tail. 
The sharp and bony tail tip allows the fish to burrow quickly backwards!The coral rubble was crawling with these large Black spotted flatworms (Acanthozoon sp.).
There were also lots of fanworms which were too nervous for me to photograph.Even in sandier areas, we must watch our step.
Here is a Horn-eyed ghost crab (Ocypode ceratophthalmus) half buried in the sand. It's easy to overlook it.
This is a Horn-eyed ghost crab that is out and about. There were lots of them quietly foraging on the high shores.There was quite a bit of seaweeds on the shores today. And among them I spotted this tiny slug that seems to be a nudibranch.
I don't know what it is.But the most exciting slug on the shore today was a reprise by the Moon-headed side-gill slug (Euselenops luniceps).
We last saw these adorable polka-dotted slugs on Sisters Island in Apr 07, and one was also sighted on Chek Jawa recently. Are they seasonal?Side-gill slugs belong to Order Notaspidea and and are NOT nudibranchs. They get their common name because they have a large plume-like gill between the mantle and the foot, usually on the right side of the body.
Here's a look at the underside of the slug with a glimpse of its side gill.
A closer look at the side gill.The rest of the team saw lots of fantastic stuff like sea snakes, 'Nemos', mushroom corals, more slugs and octopus and fish, and a tree climbing hermit crab. We'll just have to wait for them to blog about these.
We ended the trip with a lovely cake provided by November, and lots of yummy home-made cookies by Yue Yun. And of course a toast to our shores and to more adventures in 2009!Here's what the rest of the team saw:
- A fantastic video clip of two 'Nemos'! by Andy on his sgbeachbum blog.
- Another fabulous video clip of the side-gill slug swimming! by Andy on his sgbeachbum blog.
- Sea snakes, hermit crabs and ghost crabs galore and other sightings by November on her Midnight Monkey Monitor blog.
The original Sisters Islands ...
Originally, the Sisters Islands were ringed by reefs.
These reefs have since been reclaimed to form swimming lagoons.
Reclamation added 5.4ha to the islands and were done in 1974 and 1975 at a cost of $1.7 million, from The Coastal Environmental Profile of Singapore, By Lin Sien Chia, Habibullah Khan, L. M. Chou on google books.What is the future of the Sisters Islands?
In the Master Plan 2008 (which has been gazetted earlier this month), the plans for the Sisters Islands are all light green for "sports and recreation". (Sadly, the map omits the intertidal areas and reefs of the islands).
In the Parks and Waterbodies Plan, a chunk of St. John's Island is designated a Nature Area, while the Sisters Island and the waters around them is designated a Marine Nature Area. This is the only designated Marine Nature Area in Singapore so far.
What does this mean?
It is reassuring that the beautiful marine ecosystems on the Sisters Islands are recognised in development decisions.More links
- About the Sisters Islands the legend surrounding them, media reports, latest blog posts, photos and more, on wildsingapore.
- More about the plans for our Southern Islands in the Master Plan 2008, on the wildfilms blog.
- Sisters Island Coral Reef survey in Jul 08 with the results of the survey on the Blue Water Volunteers website.
- Sisters Island Coral Reef Survey data, earlier data on Coral Reefs of Singapore
