Wednesday, August 21, 2013

Huge sea star and orange flatworm at Chek Jawa

Exactly one month ago,  a small team of us visited Chek Jawa for an intertidal survey trip. During that trip, we covered the Eastern and Northeastern part of Chek Jawa. You can read about my sightings from my earlier post about that trip.

Today we visited Chek Jawa again for another intertidal survey, but we started from the Southern side (in front of House No. 1) and worked our way towards the Chek Jawa front beacon.
Chek Jawa Front beacon
We started off by checking the pillars of the jetty in front of House No. 1 at Chek Jawa.
The first animals that I encounter was the striped hermit crab (Clibanarius infraspinatus). This hermit crab is very commonly seen on our shores and usually orange, but the one I saw was blue. Such colour is not commonly seen.
Striped hermit crab in blue
This looks like a the striped sand anemone. It is slightly retracted, showing only the tentacles with white bands.
Striped sand anemone?
This poor whelk has its shell surface almost fully occupied by a snail-hitching sea anemone.
Snail-hitching sea anemone on a whelk.
What kind of anemone is this? Hmm.... I am not able to identify this anemone. It has a dark coloured band that spreads across the width of the anemone.
Unknown anemone
On the pillar, there were a number of flying insects flying around and I managed to capture on that is resting on the pillar. It looks like some kind of fly.
Flying insect resting on the pillar.
Higher up the pillar, the lined nerite snail (Nerita articulata) leaves a trail of slime on the pillar surface where ever it moves. You cannot put the nerite snail back where you took from as the snail will retract into its shell when disturbed. This will cause the suction between the surface and snail to be cut off.
Line nerite snail
Can you spot the animal in this pictures?
Who and Where am I?
It is a juvenile purple climber crab (Metopograpsus sp.). Can you see it?
Purple climber crab
A poor fish swam too close to a haddon's carpet anemone (Stichodactyla haddoni) and got stung. The anemone them slowly pulls the stunned fish towards its oral disk. 
Carpet anemone caught a fish
The moving of the fish towards the anemone's oral disk was captured on video, but I had to abandon it due to the noisy and annoying mosquitoes pestering around me.

On other pillars, I spotted a blue-spotted flatworm (cf Pseudoceros indicus) on a group of ascidian looking animal. Could it be feeding on them?
Blue-spotted flatworm.
There were quite a number of sea fan or gorgonians towards the end of the jetty.
Sea fan
Candelabra sea fan (Euplexaura sp.)?
Gnarled sea fan (Echinomuricea pulchra)?
While checking out the sea fans, Mei Lin accidentally encountered a mangrove whipray (Himantura waiga) right in front of her foot and she froze on the spot for a short while. We were in about shin deep waters.
Mangrove whipray
There are plenty of biscuit sea stars (Goniodiscaster scaber) at Chek Jawa and they come in various sizes.
Biscuit sea star
Near the beacon, there are two knobbly sea stars (Protoreaster nodosus), though they looked kind of lonely together.
Knobbly sea stars
Along the way to the beacon, I came across a huge cake sea star (Anthenea aspera). This is the largest cake sea star I have seen. I have a photo of my size 8 bootie next to the sea star for size comparison.
Cake sea star
Comparison between sea star size and sponge.
Sea star size compared to my size 8 bootie
It's bigger than my hand!
Such a huge cake sea star makes photography of details a lot easier. Finally, I could get a good picture of the tiny bivalve pedicellariae on the underside of the cake sea star.
Tiny bivalve pedicellariae
Mei Lin spotted two little ruby flatworms (Phrikoceros baibaiye). It is very easy to miss this flatworm as they looked like orange melted sponge or ascidians. They are quite active and move rather fast, but not the fastest flatworm I had encounter. (*warning* The colour may be too striking for your eyes.)
Little ruby flatworm
Moving away quickly.
While heading to the Chek Jawa Front beacon, this poor smooth snapping shrimp (Alpheus sp.) was stranded on the sand.
Right side profile
Smooth snapping shrimp stranded on sand
Of course, I took the snapping shrimp and place it in a nearby shallow pool with a burrow. The shrimp was happy to be back in water and it went into the burrow quickly.
Smooth snapping shrimp in shallow pool.
I saw the red shrimp again at Chek Jawa in a vast patch of seagrass. However I did not observe the head in burrowing behaviour I saw yesterday at Pulau Sekudu.
Red shrimp hiding among seagrass and sea lettuce seaweed.
As we end the trip, a red ribbon worm emerges from its burrow and stayed stationary on the sand for what we would considered as a long period of time. It is usually very difficult to photograph this worm as they retract into their burrows at the slightest sense light or disturbance.
Red ribbon worm
My second intertidal survey trip to Chek Jawa is made possible with permission from NParks. Also not forgetting the crazy small group of us who woke up around 2 am on a working day for this trip.

Do not ask me how I did it or how manage to survive the work day because I have no clue how I manged it but somehow, I did and survived.

Posts by others on this trip:
Kok Sheng - A glimpse of the glorious beacon area at Chek Jawa
Mei Lin - Chek Jawa checkup - 21082013
Ria Tan - Alive at the Chek Jawa beacon

My past post on Chek Jawa intertidal:
My first Chek Jawa intertidal survey trip

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