Monday, June 09, 2008

Wonderful St John's

Went to St John's Island a few times recently, and thought I'll just put up a quick summary of the various interesting stuff we saw there in one blog entry :)

coral reef
St John's Island probably has one of the prettiest intertidal coral reef in Singapore!

soft cora
I've seen this soft coral several times, but some how just couldn't find its exact ID.

St John's Island is one of the best places in Singapore to find flatworms. This is one of those that usually come out creeping around on the dry rocks during low tide. Not sure of its ID as well.

flatworm, Pseudoceros sp
Personally, I prefer the marine flatworms, as they look so elegant swimming or sliding along. The above is probably a Pseudoceros sp.

marine flatworm, Acanthozoon sp.
Here's another marine flatworm (Acanthozoon sp.) commonly seen on out shores. In fact, I saw at least 4 other types of marine flatworms over these few trips.

hairy sap-sucking slug
During one of our trips, there were lots of little hairy sap-sucking slugs on the green bryopsis seaweeds. Can you find the slug among the seaweeds above? The slugs feed on the sap of the seaweed, and can in fact retain the chloroplast of the seaweed in their to do photosynthesis to obtain additional nutrients!

leaf slug, Elysia ornata
There were several leaf slugs (Elysia ornata) too, and they are also sap-suckers.

Phyllodesmium briareum
St John's is also a great place to find nudibranchs, including some of the less commonly seen ones. I was really quite excited to find not one, but two species of Phyllodesmium nudibranchs there! The above was a Phyllodesmium briareum, which feeds on briareid soft corals like Solenopodium sp. and Briareum sp. I've seen this nudibranch several times on our shores, and at St John's, we even saw it feeding on a soft coral!

Phyllodesmium magnum
There were lots of sinularia soft corals (Sinularia spp.) on our shores, and I was really hoping to eventually see a nudibranch that feeds on them. And finally on one of the trips, my wish was granted! The above is a Phyllodesmium magnum, which feeds on sinularia soft corals.

Ceratosoma gracillimum
This was also the first time I saw a Ceratosoma gracillimum! A very pretty nudibranch which my diver friends often encounter while diving at Pulau Hantu!

Phyllidiella nigra
And this is a black phyllid nudibranch (Phyllidiella nigra), which is rather common on our shores too. Studies shown that phyllids are very toxic sea slugs, and they release a milky-looking toxin into the surrounding waters when they are stressed, and could easily kill a whole tank of fishes!

Glossodoris atromarginata
Another nubibranch we saw was this marginated glossodoris nudibranch (Glossodoris atromarginata).

Pteraeolidia ianthina
This is also a nudibranch (probably Dermatobranchus sp.). Saw several other types of nudibranchs during these few trips as well, such as the blue dragon (Pteraeolidia ianthina), the polka dot nudibranch (Jorunna funebris) and pustulose phyllid nudibranch (Phyllidiella pustulosa) etc.

Cypraea ovum
There were many pretty cowries too, such as this ovum cowrie (Cypraea ovum). These little snails feed on algae.

Chicoreus torrefactus
There were many beautiful murex snails (Family Muricidae) as well. Not sure of the exact ID though. Update: Understand from a mollusc expert and also from Ivan that it should be a Chicoreus torrefactus. Thanks to both!

Octopuses were a common sight at St John's, and sometimes, when you are lucky, they are not camera shy too!

hairy hermit crab, Dardanus lagopodes
One of the fellow shore volunteer found this hairy hermit crab (probably Dardanus lagopodes) in a cone snail shell. You can even see part of it's soft abdomen in the above picture.

ghost crab, Ocypode ceratophthalma
On our way to the jetty, we had a surprise find - a ghost crab (Ocypode ceratophthalma). They usually only come out when it's dark, so not sure why the one above was still out in the day.

coastal horseshoe crabs, Tachypleus gigas
We also found a pair of coastal horseshoe crabs (Tachypleus gigas). The one on top is the male, while the one below is the female.

starfish, Archaster typicus
In the sandy lagoon, there were lots of sand-sifting sea stars (Archaster typicus). These sea stars were once very common even on our mainland shores, but these days, due to over collection and loss of habitat, they can hardly be found on our mainland shores thought they are still rather common on our various islands.

green brittle stars
ST found this pair of green brittle stars on one of the trips. I've never seen them before!

feather star
Several feather stars were also spotted.

sea cucumber
I found quite a few of these little sea cucumbers at the rocky shore.

stonefish sea cucumber, Actinopyga lecanora
A few stonefish sea cucumber (Actinopyga lecanora) were also spotted.

copper-banded butterflyfish, Chelmon Rostratus
In some of the tidal pools, pretty little copper-banded butterflyfishes (Chelmon Rostratus) were swimming around.

blue-spotted fantail ray, Taeniura lymma
But take note, there were also stingrays around! The above is a blue-spotted fantail ray (Taeniura lymma).

Stonefish, Synanceia horrida
And of course, Mr Stonefish (Synanceia horrida). It has spines on its dorsal fins that can inject a highly toxic venom! So if you are not an experience shore person, I'll really advise you not to wander around a rocky shore on your own! Stepping on a stonefish can land you in a hospital for a few weeks!

water monitor lizard, Varanus salvator
We found this water monitor lizard (Varanus salvator) lying still in the water. Have no idea what it's doing, but it hardly move even when we got rather close to it. It was only after a while that it started running away into deeper waters.

great-billed heron, Ardea sumatrana
We also saw the tallest resident bird in Singapore, the great-billed heron (Ardea sumatrana), at St John's Island!

white-bellied fish eagle, Haliaeetus leucogaster
And also, the biggest resident bird-of-prey in Singapore, the white-bellied fish eagle (Haliaeetus leucogaster)! In fact saw several of them hunting for fish in the shallow waters!

Well, St John's Island is indeed a great place with a beautiful shore! Will love to go back again in the near future :)


Ivan said...

The muricid is probably a Chicoreus species, possibly C. torrefactus as shown in "A Guide to Common Seashells of Singapore".

Ron Yeo said...

Thanks Ivan. Been too lazy these days to check up the seashell guide. Haha :P

Have actually checked with a mollusc expert just now, who told me it looks like a C. torrefactus too.

Btw, he also told me that in the seashell guide, the picture provided for C. torrefactus is probably wrong, and it's actually a C. brunneus.

greenwoman said...

is it possible that I saw a Nankeen Night heron during the day on the shore of the Sg river near boat quay? Didn't get a great pic, but I thought I saw yellow legs.
Thanks! Visitor to sg

Ron Yeo said...

I don't think we have the Nankeen Night Heron in Singapore, but we do have the Black Crowned Night Heron though.

greenwoman said...

Thanks, That's most likely it. Checked a google image!