30 June 2011

Fishes and other surprises on oil-slicked Tanah Merah

What a delight to encounter this fish on oil-slicked Tanah Merah!
I seldom see the Eightband butterflyfish (Chaetodon octofasciatus), and usually only near reefs. But Kok Sheng had seen a group of them at Tanah Merah, among the corals growing on the outer seawalls.

My first sightings on this shore after the oil spill includes this large spotted black flatworm (Acanthozoon sp.) which is commonly seen on our other shores especially near reefs.
Also my first sighting of a brittle star on this shore after the oil spill!
Fishes remain abundant. Today, I also saw two large fat Brown spotted moray eels (Gymnothorax reevesii).
Uh oh, here's a fish sighting that's not much welcomed. It's Mr Stonefish! I am very careful on this shore where the Hollow-cheeked stonefish (Synanceia horrida) is quite plentiful. Luckily I saw him before I stepped on him!
Here's two fishes that look very similar. The lower fish that is yellowish is a true scorpionfish, the Painted scorpionfish (Parascorpaena picta). Above it, the bluish fish is the False scorpionfish (Centrogenys vaigiensis) which is actually a grouper. When they are next to one another, it's easier to tell them apart.
There were many other kinds of fishes too. I saw many small Bengal sergeants (Abudefduf bengalensis), several small Scissortail sergeants (Abudefduf sexfasciatus), many cardinalfishes (Family Apogonidae), damselfishes (Family Pomacentridae) large and small, several Chocolate hind (Cephalopholis boenak), a small Pink-eared emperor (Lethrinus lutjan) and many White-spotted rabbitfishes (Siganus canaliculatus). Also several Seagrass filefishes (Acreichthys tomentosus).
I saw many different kinds of halfbeaks (Family Hemiramphidae).
I almost missed this small and well camouflaged Fringe-eyed flathead (Cymbacephalus nematophthalmus).
There were lots of crabs out on the shore today. On the sea walls were many small Purple climber crabs (Metopograpsus sp.), I saw one large Red egg crab (Atergatis integerrimus), many Blue-tailed prawns (Family Penaeidae), one large Mud crab (Scylla sp.), and several Ghost crabs (Ocypode cerathophthalmus). There were many small Flower crabs (Portunus pelagicus), and many small Swimming crabs (Family Portunidae) of all kinds. Today, I didn't see any Spotted moon crabs (Ashtoret lunaris).
I saw this little swimming crab catch a fish, right in front of me! It was very fast!
I managed to get a glimpse of a few Saron shrimps (Family Hippolytidae). But they rapidly slunk away into hiding after a few shots.
I also saw two of these pretty White spotted hermit crabs (Dardanus megistos).
I saw several small squids (Family Loliginidae). I'm not sure if these two are the same kind. I also saw one small Ornate leaf slug (Elysia ornata).
I saw about ten Common sea stars (Archaster typicus) widely spaced apart. Only a few were near one another. I didn't see any in 'mating' position.
I saw the usual number and variety of corals. Most on this shore are Favid corals (Family Faviidae). There many large colonies.
The Favid corals come in many colours, some were a little pale.
I saw two corals which might be Bracket mushroom corals and the small Circular mushroom corals (Family Fungidae) that I saw last month.
I also saw two small Anemone corals (Goniopora sp.), something that looks like a small Encrusting disk coral (Turbinaria sp.) and a few tiny to small colonies of Flowery disk coral (Turbinaria sp.).
Although most of the hard coral colonies seemed alright, I saw this large Pore coral with bluish portions that is probably a sign of disease.
Some of the hard corals were rather pale.
I saw one small Disk corals with a pale edge and pale polyps, while another large Pore coral colony had a bluish layer on part of it.
Some of the large Pore corals (Porites sp.) I saw today were rather pale.
I saw one Peachia anemone (Peachia sp.) and one Haddon's carpet anemone (Stichodactyla haddoni) in deeper water with an anemone shrimp. I also saw one small mouth cerianthid. There were two large patches of Button zoanthids or colonial anemones (Zoanthus sp.).
The two large patches of Smooth ribbon seagrass (Cymodocea rotundata) seem even larger, with long blades mostly clean of growths. The Haddon's carpet anemones (Stichodactyla haddoni) that have settled among these seagrasses are also still doing well. The patch of Sickle seagrass (Thalassia hemprichii) that has chomped blades again. The Spoon seagrass (Halophila ovalis) which I saw last month for the first time, are still there. The leaf blades are tiny but they seem clean and green.I came across three clumps of Tape seagrass (Enhalus acoroides) with long blades that seemed mostly green and clear of growths.
The most abundant seaweed today were Mermaid's fan (Padina sp.) and crunchy pom pom seaweed that was growing on ropes and extensively on rockier parts of the shore, together with clumps of green Codium seaweeds (Codium sp.). There were some small but lush clumps of Sargassum seaweed (Sargassum sp.).
There were several Acorn worms (Class Enteropneusta). These long buried worms produce long coils of 'processed sand'. Most of the coil seemed clear of dark stuff.
Everywhere, there was a sheen of oil on the otherwise clear water. I didn't walk the entire high shore to check for crude, but most of sandy bottom seemed clean. I didn't meet anyone on the shore today.
The low spring tide starts again! Tomorrow, we hope to show Dr Daphne the strange burgundy sea anemones at Punggol and perhaps we might find more anemones yet!

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