30 November 2011

Tanah Merah: return of the crabs

It was nice to see the return of some familiar crabs on this shore that was hit by a massive oil spill in May 2010.
But here's a strange looking crab! I'm not sure what it is. It was in deep water and scuttled off into a crevice before I could take a closer look.

When I first arrived, I noticed what seem to be Soldier crabs (Dotilla sp.) on the high shore! They hid too quickly for me to photograph. But these rosettes in the sand are typically made by these crabs. If indeed they are Soldier crabs, it will be my first sighting of them on this shore!
For the first time since the oil spill, I saw four Red egg crabs (Atergatis integerrimus)! I also saw one Velcro crab (Camposcia retusa). There were many Swimming crabs (Family Portunidae) of all kinds, I saw a pair of Flower crabs (Portunus pelagicus) and also many Spotted moon crabs (Ashtoret lunaris).
There were also lots of hermit crabs on the shore, including the Banded hermit crab and several pretty Spotted orange hermit crabs (Dardanus megistos). Shrimps were also abundant especially after dark. I also saw many Saron shrimps but couldn't get a closer look at them.
There were still many Haddon's carpet anemones (Stichodactyla haddoni) in the two large patches of Ribbon seagrasses. And almost all of them had a pair of Five-spot anemone shrimps (Periclimenes brevicarpalis).
The shore seems to be doing well. Teeming with fishes, corals and crabs! I only saw one large patch of Button zoanthids or colonial anemones (Zoanthus sp.).
As night fell, fishes of all kinds became more lively. Among those I saw were: Copperband butterflyfish (Chelmon rostratus), Painted scorpionfishes (Parascorpaena picta), filefishes (Family Monacanthidae), damselfishes (Family Pomacentridae), medium sized Bengal sergeants (Abudefduf bengalensis). Also many Cardinalfishes (Family Apogonidae) and gobies (Family Gobiidae).
This is probably a Streaked rabbitfish (Siganus javus) which I don't often see. This kind of rabbitfish has a dark tail with yellow fins and streaks on the lower body. Tanah Merah is one of the few places where I often see different kinds of rabbitfishes.
I saw a small cluster of about 10 Common sea stars (Archaster typicus). Many were in mating position.
As usual, the squids (Family Loliginidae) come towards my torchlight! This one zoomed towards me, then came to sudden stop before zooming away in the opposite direction.
The large hard corals seem to still be doing well. I didn't come across any that were bleaching.
I saw one small Disk coral (Turbinaria sp.), many large and medium sized Pore corals (Porites sp.) and Favid corals (Family Faviidae).
I only saw one Peachia anemone (Peachia sp.) and another larger anemone that might be a Plain anemone.
There were many fluffy fan worms both the brown banded ones and orange ones. Also many Thumbs up sea squirts (Polycarpa sp.), although most were covered in a thick layer of fluffy growths.
I saw two Spotted black flatworms (Acanthozoon sp.)!
The two large patches of Smooth ribbon seagrass (Cymodocea rotundata) seemed to have grown even larger. The patch closer to the main seawall seems to be covered in growths and some part of the patch had blades that were cropped short. The other patch seems alright. The small patch of Tape seagrass (Enhalus acoroides) in the middle of the lagoon seems alright with long leaf blades and several female flowers! I missed the patch of Sickle seagrass (Thalassia hemprichii) and didn't come across any Spoon seagrass (Halophila ovalis). The only abundant seaweed I saw today was Mermaid's fan (Padina sp.. I was rather surprised to see no Sargassum seaweed (Sargassum sp.).
It was a nice surprise to see a very clean upper shore with almost no plastic trash.
Alas, litter is still accumulating on the low shore. Ending up on marine life like seagrasses and carpet anemones. International Coastal Cleanup Singapore (ICCS) is starting a year-round effort to keep this shore clean. They are looking for volunteer managers to lead in this effort. You CAN make a difference for our shores. More details on their blog.
On some parts of the shore, there was still the smell of crude. And beneath a thin layer of sand, crude still sparkling black more than one year since the oil spill hit this shore.
I even came across what looks like oil spill booms.
Just before leaving the shore, I came across the only nudibranch of the day!
Jorunna funebris is quite commonly seen on our reefs, and I would like to think that it means things are going well on this reef.

More about the oil spill on this blog and on the Oil spill facebook page.

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