Monday, July 11, 2016

Coral Bleaching in Terumbu Semakau

Our final survey for this season of low spring tide would be to check out the coral bleaching at Terumbu Semakau, a patch reef off Semakau Landfill.

How are the corals doing? Unfortunately, they are not doing well.

I came across this patch of Acropora corals (Acropora sp.) during Christmas last year and checked them out again on this trip. All of them are now looking pale which is a result of photosynthetic algae leaving the coral colonies.

Some of the branches have in fact died off and become part of the coral rubble.

The corals that congregate at the reef edge now form a "white line" as the bleaching is going on. They now become more conspicuous.

This reminded me of the mass coral bleaching in 2010 and the photo above was also from Terumbu Semakau. It took a few months for recovery to take place.

Looking across to Semakau East, a shore off the mangroves of the original Pulau Semakau, one can see even more bleaching corals.

This is once again similar to what we observed in 2010 as shown through the old photo above.

The corals that are submerged are also bleaching.

Here's more hard corals that are affected. In general, we estimate about 50% of the hard corals and 50% of the leathery soft corals are bleaching. In addition, we estimate 20% of the corals have died recently.

Here's a look at the bleaching Leathery soft corals (Family Alcyoniidae).

On the brighter side where we look at the cup as half full instead of half empty, 50% of the hard corals are still alright and are not bleaching. Above is an assortment of different hard corals that still look fine.

The sea anemones are not spared as they too also contain photosynthetic algae that would exit their host during high sea surface temperature. Above is a collage of both a bleaching and non-bleaching (or slight bleaching?) Pizza anemone (Cryptodendrum adhaesivum).

The Magnificent sea anemones (Heteractis magnifica) seem to be alright. I didn't see any of these anemones bleaching.

Ria came across two of these uncommon Merten's carpet anemone (Stichodactyla mertensii). The Merten's carpet anemone has shorter tentacles that densely cover the oral disk. It also has colourful bumps on its body column.

The Bubble tip sea anemones (Entacmea quadricolor) are usually badly affected by bleaching events. All of those that I saw were badly bleached.

Some of the Bubble tip sea anemones are home to the Tomato anemonefish (Amphiprion frenatus). And it's quite sad if these bleached sea anemones die off because that would be the nemos would lose their home.

Here's another view of the nemo in the bleached anemone. I also took a video as shown below.


And once again, it reminded me of what I observed in 2010. The photo above was taken during 2010's coral bleaching period.

It was nice to see the Fluted giant clam (Tridacna squamosa) that the team found previously. It looks fine and is not bleaching.

This Banded file snake (Acrochordus granulatus) is usually sighted at or near Semakau. Surprisingly, some of them tend to be covered with algae. Not too sure why.

Let's hope that the coral bleaching will end soon. Some of the corals are already dying or dead and we do wish for speedy recovery! 

More photos of the trip can be found here:

No comments:

Related Posts Plugin for WordPress, Blogger...