12 September 2010

Sea snake at Sisters!

A beautiful and gentle creature, it's always a delight to encounter the Yellow lipped sea krait (Laticauda colubrina).
We were out at Sisters island to check up on the bleaching situation during the evening tide yesterday.

I'm really excited about seeing the snake! My first since Nov 09 on Pulau Semakau. Sea snakes need to breathe air so they come up now and then to get a quick sniff. Like all snakes they have a forked tongue that they use to sense their surroundings. In the photo on the right, an accidental capture of a tiny bit of the tip of its tongue.
I'm also excited to see two Tiger-tailed seahorses (Hippocampus comes)! I haven't seen one here since 2003. The seahorses are actually quite well camouflaged. In fact, Ivan saw FOUR of them here. I missed the other two!
In fact, many creatures on the reef are well camouflaged. Here is a rather large Fringe-eyed flathead (Cymbacephalus nematophthalmus). Can you spot it?
Here's a closer look at the golden lashes on this fish. I saw many of these fishes and they were relatively large.
Here's more fishes that are well camouflaged! The Painted scorpionfish (Parascorpaena picta), Longspined scorpionfish (Paracentropogon longispinis) and the False scorpionfish (Centrogenys vaigiensis) which is actually a grouper. I also saw a small Three-spined toadfish (Batrachomoeus trispinosus).
Other well camouflaged animals include this Very hairy hermit crab. Although relatively large, its hard to spot. Even when I turned it over to have a closer look, its hairy limbs allow it to blend in with its surroundings.
Another master of camouflage is the Reef octopus. I saw two small ones, although in the past, I used to encounter many and large ones. Perhaps it's not the right season as these animals don't have a very long lifespan.
Not camouflaged at all, is the brightly patterned False clown anemonefish (Amphiprion ocellaris). With patience and luck, we can spot these fishes on our reefs.
There were lots of other fishes out and about. Among those I saw were a young Three-spot damselfish (Pomacentrus tripunctatus), many Bengal sergeants (Abudefduf bengalensis), and the two fishes in the last row which I have yet to figure out.
Abundant were Tropical silversides (Atherinomorus duodecimalis), Spotted glass perchlets, halfbeaks (Family Hemiramphidae) and gobies of all kinds (Family Gobiidae).

Crabs were busy too. There were many swimming crabs (Family Portunidae) of all kinds out on the shore. The Red swimming crab (Thalamita spinimana) seems to be working on a Black-lipped conch (Strombus urceus).
I saw several Floral egg crabs (Atergatis floridus), several large Red egg crabs (Atergatis integerrimus) and two Mosaic crabs (Lophozozymus pictor). All these crabs are highly poisonous to eat and cooking doesn't destroy their toxins.
The only nudibranch I saw was this Glossodoris atromarginata. It's next to a more camouflaged snail, probably a Dwarf turban snail (Turbo bruneus).
Other interesting sightings by the rest of the team include Chay Hoon's sighting of a small stonefish, and a stingray (fortunately, no one is hurt by these!) and Russel saw the Ashy pink sea cucumber (Holothuria fuscocinerea); and lots more!

But how's the coral bleaching at Sisters?

The Sisters Islands are a pair of island just off the main city centre. We are visiting Big Sisters Island which also has a nice rocky shore and coastal forest.
Here's a view with Little Sisters just opposite us. Both islands have been reclaimed to form man-made lagoons, but the reefs have thankfully returned.
What a relief to see that most of the hard corals are not white. It is also now clearly Sargassum Season with the brown Sargassum seaweed (Sargassum sp.) forming a golden carpet over the reefs. This is makes it tricky to explore the reefs as we don't want to crush corals or accidentally step on a stonefish. So we generally avoid stepping into weedy areas.
There are still some leathery soft corals (Family Alcyoniidae) and hard corals that are partially bleaching. Here, even the Sea mat zoanthids (Palythoa tuberculosa) are still bleaching.
A big patch of Button zoanthids (Zoanthus sp.) were still bleaching. But I didn't come across a totally white hard coral colony. The corallimorphs (Order Corallimorpharia) that I saw were alright.
Another view of the typical bleaching situation. It looks like the bleaching is over at Sisters Island.
Some parts of the outer reef are colourful with healthy corals and sponges. I saw the usual sponges normally seen here and they seemed alright.
Among the corals that I saw in good health were one colony each of Sandpaper coral (Psammocora sp.), Anemone coral (Goniopora sp.), Disk coral (Turbinaria sp.), and several Carnation corals (Pectinia sp.). I also saw a large Lettuce coral (Pavona sp.) that was not bleached, although large parts of it were dead.
Many of the Favid corals (Family Faviidae) I saw were recovering or well recovered without too many dead spots.
I wasn't sure what this was until I got home to look at the photo. It's a tiny colony of the rare Horn coral (Hydnophora sp.), with the typical conical corallites surrounded by a fringe of tentacles.
While many corals seemed to have recovered, I saw signs of some that recently died (we can still see the corallites which are being covered by scum) and some that only made a partial recovery.
Sisters Island usually has lots of Circular mushroom corals (Family Fungiidae). I saw a cluster that seem to be recovering with some that seem to be totally recovered.
Here's a closer look at a cluster of recovering and recovered mushroom corals.
The Acropora corals (Acropora sp.) that I saw seemed to be recovering but with much of the colony dead.
I did not see any living colonies of Anchor corals (Family Euphyllidae), Cauliflower corals (Pocillopora sp.), Brain corals (Family Mussidae), Galaxy corals (Galaxea sp.).

On my trip here about a month ago, I saw many Pore hard corals (Porites sp.) with bluish bands. Today I only saw this one patch of blue. The Pore hard corals I saw on other parts of the shore seemed alright, but I didn't manage to have a look at the ones I saw last month.
Frilly anemones (Phymanthus sp.) are common here and most seem to be doing well, with a few still showing white tentacles or white portions on their tentacles.
I noticed a Giant carpet anemone (Stichodactyla gigantea) producing a stream of white milky substance from it's 'mouth'. Well, anemone don't have an anus and only have one opening for eating and expelling waste. Also, this is where anemones release eggs and sperm. I'm not really sure what is going on.
In general, my feeling is that the reefs growing outside the seawalls seem alright. But there seems to a lot less live coral inside the large lagoon, which is also becoming rather shallow as it inexplicably is being filled up with sand and sediments.

We're out on an evening tide and enjoy a great sunset!
As darkness fell away from the mainland light pollution, we enjoy the spectacle of a star-studded clear night sky. With a thin cresent moon, and the bright light of Venus just above the moon!

I'm glad to see that bleaching on the Sisters Island seems to have stopped, and hope eventually there can be a full recovery of the reef.

Other posts about this trip
  • Russel with gorgeous sunset photos and more
  • Chay Hoon with her amusing "Letter of the Day" as most of the special finds began with the same letter.
Meanwhile, Mei Lin was at another stretch of Tanah Merah to check up on oil spill effects.


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