29 July 2010

Oil-slicked Tanah Merah: Fishy surprises!

Today we check up the other oil-slicked lagoon at Tanah Merah. And what a surprise to see a Brown-spotted moray eel (Gymnothorax reevesii)!
In fact, we saw quite a few interesting fishes today.

The Hollow-cheek stonefish (Synanceia horrida) is very common on Tanah Merah. And I saw one today that was very clean and not covered with sediments or other growths.
There were lots of White-spotted rabbitfishes (Siganus canaliculatus) and this one jumped out of the water and got stranded. I put it back after quickly snapping a shot. Andrew found a tiny Copperband butterflyfish (Chelmon rostratus)!
I also saw many Ornate lagoon-gobies (Istigobius ornatus). I could only see them when they moved, they are so well camouflaged against the sand!
There are lots of tiny little fishes in the shallow pools. I'm not sure what they are, but they could be young Perchlets (Family Chandidae).
In the deeper water, zooming past us in the murk we saw what looked like a large Thread-fin. I also a large Needlefish (Family Belonidae).

It was much easier to check out the rock wall today so I had a look at the corals growing there. Among the hard corals seen were one small Flowery disk coral (Turbinaria sp.) and several small Pore corals (Porites sp.). They were not bleached.
Most of the hard corals found here are Favid corals (Family Faviidae), and all those I saw were not bleaching. Except for one.
I saw one large Haddon's carpet anemone (Stichodactyla haddoni). It was not bleached and it still had a pair of anemoneshrimps!
I took these photos of Mr and Mrs Anemoneshrimp (Periclimenes brevicarpalis) underwater as the water was too murky for Big Cam.
There were two large patches of Button zoanthids (Zoanthus sp.) and they looked alright.
I saw only one Common sea star (Archaster typicus). I wonder why there are so few in this lagoon. In the other Tanah Merah lagoon that we visited yesterday, there were a lot more of these sea stars.
The shore is still almost totally covered with the Bazillion snails (Batillaria zonalis). The opposite of the sea star situation, the other lagoon we visited yesterday has much fewer Bazillion snails.
There were still plenty of Dubious nerites (Clithon oualaniensis) on the sandy shore. On the rock walls, I saw one Dolphin snail (Angaria delphinus), many Planaxis snails (Planaxis sulcatus) and various kinds of Nerite snails (Family Neritidae).
There is a stretch of cleaner sand in the middle of the lagoon. Here, there were lots of signs of living crabs. From little sand balls, probably made by the Sand bubbler crab (Scopimera sp.) to larger sand balls, probably made by the Soldier crab (Dotilla sp.). On the high shore, there were many burrows of Ghost crabs (Ocypode ceratophthalmus).
I saw many living Ribbed venus clams (Family Veneridae) on the sandy shores today. Most were small.
Some other creatures I saw: One living Fan shell clam (Family Pinnidae), one Peachia anemone (Peachia sp.), one Striped hermit crab (Clibanarius sp.), several Large false limpets (Siphonaria atra) on a rock. There were also many Flower crabs (Portunus pelagicus) but I didn't see any prawns.
I saw many Acorn worms (Class Enteropneusta) which were found even near the areas which had grey muck. Andrew saw one Peanut worm (Order Sipuncula). I'm worried when I see this usually-buried worm above ground.
The fan worms (Family Sabellidae) I saw today seemed normal.
At the water's edge, a Striated heron is on the hunt.
I saw more seaweeds today than yesterday: Lots of Padina sp., much pom pom red seaweed, many bunches of Codium sp. and one Solitary fan seaweed (Avrainvillea erecta).
There's lots of Sargassum seaweed (Sargassum sp.). And Chay Hoon found two tiny seahorses (Hippocampus sp.) in them. She showed me this one. I don't know how she can find these superbly camouflaged and tiny creatures!
There is a small patch of Sickle seagrass (Thalassia hemprichi) here and it seems mostly alright although many leaf blades are starting to bleach.
The clump of Tape seagrass (Enhalus acoroides) on the high shore is blooming! I counted 8 female flower stalks. The leaves, although short, seemed clean and green.
The small clump of Tape seagrass in deep water also had flowers but the leaf blades didn't look very good.
Andrew has a look at the large patches of Smooth ribbon seagrass (Cymodocea rotundata) that are growing here.
Most of the leaves are still green and not bleached, although there are many with blackened tips. Besides having to cope with a scum of crude floating on the water, the poor seagrass is also suffocated by litter.
There is still a long line of crude on the low-water mark.
Beneath the thin layer of sand, the crude sparkles as on the day it landed on the shore two months ago.
There is a wide band of grey stuff on the shore and some of this is being covered with a fuzz of white filaments. The Bazillion snails don't seem to mind the grey stuff or the white fuzz. In fact, are they eating it?
The grey muck coated with white fuzzy filaments form a band in the middle of the lagoon.
The whitish stuff is found amongst the Smooth ribbon seagrass. I hope it doesn't affect their growth.
On some areas, the white fuzz is being covered with green stuff, which seems to form a thin layer over bare sand.
The streams of water that run at low tide bring sheen and grey muck to the low shore. The Bazillion snails are huddled together here, probably trying to get away from the crude.
A scum of crude still forms in many parts of the lagoon.
Some parts of the rock wall has bare black rock not covered in growths like the rest of the rocks. I'm not sure what this means.
On one of the ickiest parts of the shore, there is a stake with a tag indicating that there is a study going on here. That's good! Let's hope we will find out more about how this shore is being affected by the oil spill.
Besides the oil spill, sadly, there is an abandoned driftnet on the rocks. It was too long and too well embedded for us to try to remove just the three of us, especially since we only encountered it as the tide was turning.
In the net, there was one large dead fish that looked like it died recently. Floating about in the lagoon were several other dead fishes also recently dead.
There's large debris on the low shore.
On the high shore, an entire boat has washed up and is slowly becoming filled with floating rubbish. We tried to have a look at the corals growing on the outside of the seawall, but the tide was too high. Alas, we noticed a line of floats where the corals should be and it looks like a driftnet has been placed there. Sigh.
We enjoyed a spectacular sunrise this morning!
I last visited this shore about three weeks ago. I do hope this shore will survive the many threats that we saw today.

See also our check on the other Tanah Merah lagoon yesterday.

More on the Oil Spill facebook page with links to posts and photos about checks on oil-slicked shores and other background on the spill since it first happened.

More about my previous trips to Tanah Merah.

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