13 July 2014

Terumbu Semakau: still no seagrass recovery

Are corals at Terumbu Semakau bleaching? How are the seagrasses doing?
How delightful to see False clown anemonefish in the many colourful Magnificent anemones, lots of healthy corals. But sadly, signs of a massive fish trapping system, and no recovery in seagrasses.

Terumbu Semakau is a submerged reef that lies just opposite the Semakau Landfill and next to Pulau Semakau.
There were also many False clown anemonefishes in this Giant sea anemone. Pei Yan later found 7 of these fishes in various sizes in this single anemone!
I also saw a Bubble tip anemone that seemed mostly alright and not bleaching. But I didn't see any anemone fishes in it.
Among my favourite finds for today was this sea star that has yet to be identified. I saw it too during the Mega Marine Survey's Southern Expedition survey of this reef in May 2013.
The perfectly camouflaged Spotl-tail frogfish is hard to spot. I only saw it because it was waddling about. This rotund fish doesn't swim very well and crawls on the bottom on its hand-like pectoral fins!
The fish has a lure (blue arrow) made up of a fluffy tasty looking morsel on a stick that is wiggled over its mouth. When a small fish comes too close, the Frogfish gulps it down in its large mouth. Its  eye is at the pink arrow.
We saw many of this well camouflaged Bohol nudibranch today.
Russel found four Tiger coweries. Three of them were huddled together. This large snail, although common in neighbouring countries, is rarely encountered in Singapore. Sadly, on this trip none of us came across any Fluted giant clams.
Today I saw one of each of among the most poisonous crabs in Singapore! The Mosaic crab, the Red egg crab and the Floral egg crab. These crabs have toxins that are not destroyed by cooking and should not be eaten. But the crabs are NOT venomous. Venomous creatures kill by injecting toxins, for example through stingers or a bite. Many venomous can be eaten safely, for example jellyfish.
This animal that looks like a long shoe-lace or ribbon is a ferocious predator. The Very long ribbon worm hunts prey that it can paralyse with a poison.
Terumbu Semakau has long stretches of very reefy edges crowded with all kinds of hard and soft corals. Marcus found a particularly rich stretch. I still can't walk on rubble very well, or walk very far so I only covered a small stretch not close to the reef edge.
Most of the hard corals seemed alright and not bleaching. Those that were only had patches of bleaching. I didn't see any colonies that were totally bleached.
A Flowery disk coral that looks alright, next to a partially bleaching Boulder pore coral.
While most of the Boulder pore corals were alright, a few had bluish portions especially at the top. Possibly 'sick' portions?
The Cauliflower corals, which were among the first to bleach in 2010, today were mostly alright, only a few had signs of bleaching.
The patch of Branching Montipora corals in the middle of the reef is still there. Still about 10m x 10m as I saw them in Nov 2012. None of them were bleaching.
Most of the leathery soft corals of all kinds were alright although some had bleaching or very pale patches or edges. More than half of the Asparagus soft corals I saw were yellowish or had yellowish tips. But none were completely bleaching.
The corals at Marina at Keppel Bay were also still alright.
Alas, the lush seagrass meadows that used to be here have not returned. I only saw some small patches of Spoon seagrasses, mostly heavily covered in growths. Most of the Tape seagrasses were cropped very short.
Here's what the seagrass meadows looked like when we visited in June 2010. It breaks my heart to think the seagrasses will never recover.
Near our landing point, we see a V-shaped fence-like set up of poles and chicken wire. It appears to be a funnel-like trap for fishes.
Rolls of chicken wire and stacks of metal poles were strewn on the reef. Andy also spotted an abandoned fishing net.
There was also a large channel-like depression. The pieces of dead corals pushed up on the sides of the channel suggests that it was probably formed by a boat striking the reef.
After the frightening experience yesterday of attempting to leave a submerged reef during a rising tide in stormy weather, we are all very glad to have a peaceful calm sunrise.
We had clear skies all night with the beautiful full moon overhead.
Pei Yan aka Drone Commander flew the Drone for its first dawn flight. And here, we can see the boat striked gouge, and the dark patch of Branching montipora corals above the pile of orange life vests. Alas, it is also obvious that the seagrass meadows have not returned to Terumbu Semakau. More photos on the SG Sea Drone facebook page.
We are very grateful for uneventful and calm departure from the reef. Thanks to Alex and crew of Summit Marine. This submerged reef lies just opposite the massive petrochemical plants on Pulau Bukom.
Tomorrow, a small team is checking up on the natural regeneration at East Coast Park that we had seen last  year. There are not enough low tides for us to do all our shores as often as we want to!

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