09 October 2010

Coral bleaching situation at Tuas

Yesterday, I was at Tuas with the volunteers from Schering Plough who monitor the seagrasses that lie just outside their premises.
This shore comprises seagrass meadows, sandy shores and past a shallow 'lagoon' a bit of rock sticks out marked by the Merawang Beacon. Here, there are reefier marine life and we encountered massive coral bleaching when we visited in June.

How is the situation now?

Alas, there were still many large colonies of hard corals that were totally white. They mostly seemed to be Pore hard corals (Porites sp.). Read more about bleaching on Bleach Watch Singapore.
But all the large Flowery disk corals (Turbinaria sp.) were in their usual colours. I saw five large colonies that were doing alright.
There were also several of these Thin disk corals (Turbinaria sp.) that were also not bleached. But many small disk corals were overturned. I'm not sure why. Illegal boat landing?
I saw this hard coral that might be a Sandpaper coral (Psammocora sp.). It seems to be alright.
These Starry leathery soft corals (Family Alcyoniidae) used to cover large areas of the shore. They are now in smaller clumps and appear less dark that usual. But I didn't see any that were bleached white.
I saw one large Pink flowery soft coral (Family Nephtheidae) that seemed alright, and many small clumps of the other more brownish flowery soft corals. Most were still white, only a few were brownish.
I also saw one Ball flowery soft coral.
The sea fans seem to be returning to the shore. I saw many small colonies of various kinds of sea fans growing in relatively shallow areas.
It was nice to see this pink sea fan. There used to be very large colonies of these sea fans in deeper water. I didn't get a chance to check that area yesterday.
The sponges were doing well on the shore. There was in particular a lot of the Yellow coned sponges (Speciospongia sp.) (top left photo) in particularly large patches, while there was a variety of other sponges that appear to be in good health.
The shores near the seawall, however, have changed somewhat. What was usually sandy and full of seagrass has become a rocky shore. And the seaward side of the shore is taken over by Coin seaweed (Halimeda sp.). See the TeamSeagrass blog for more.

Melted chocolate sponges (Chondrilla australiensis) have taken over large areas of the shore, both near the beacon and on the seawall side.
There is a large patch of Button zoanthids (Zoanthus sp.) on the seaward side of the shore.
Here's a closer look a the zoanthids and Melted chocolate sponge that covered large parts of the shore.
The snails and clams are still doing well on the shore. With a wide variety seen: laying eggs, mating or just doing their thing.
The sandy shores were full of life. There were several Haddon's carpet anemones (Stichodactyla haddoni) which were all not bleached. I saw several colourful peacock anemones, many tiny Pygmy squids (Idiosepius sp.) and several Painted sand stars (Astropecten sp.).
Peacock anemones are sometimes infested with these black feathery Phoronid worms (Phoronis australis). These worms seemed to be carrying white eggs (?).
I also saw several sea pens (Order Pennatulacea).
I didn't see many fiddler crabs. I managed to photograph this one, an Orange fiddler crab (Uca vocans).
I also came across a little Ghost shrimp (Glypturus sp.) attempting to dig a burrow. The second time we came across this rarely encountered animal at Tuas.
There were lots and lots and LOTS of Thorny sea cucumbers (Colochirus quadrangularis) on the shore. They were heaped on about every hard surface.
There were lots of other sea cucumbers too: several Garlic bread sea cucumber (Holothuria scabra), many many Orange sea cucumbers, one of these odd Beige sea cucumbers and near the Beacon, a Long black sea cucumber (Holothuria leucospilota). On the sandy areas, I also saw a Ball sea cucumber (Phyllophorus sp.).
There were many Purple sea cucumbers, something commonly encountered at Tuas.
Here's an odd little creature that might be some kind of sea cucumber.
I also saw many different kinds of brittle stars. From tiny ones hiding in a sponge (Ophiactis savignyi), to those in the sand showing only its banded arms, to others which were more actively moving about on the sandy shore.
It was a short evening low tide, so we enjoyed a lovely sunset.
Let's hope this shore will continue to recover!

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