Sunday, April 10, 2011

Semakau on 10 and 11 Apr 2011

I was on Pulau Semakau again during this weekend. On Saturday, we had a project Semakau survey, which I had to survey a zone on my own and coordinate the whole survey as well. On Sunday, we had a guided walk for secondary school students, but as we had enough guides, I only help with the hunting-seeking at the beginning, before going off to survey one of the mangrove areas.

The top find of the weekend for me would be this area which has several patches of the locally critically endangered Beach Tacca (Tacca leontopetaloides)! The tubers of this plant is said to be an important food source for inhabitants of many pacific islands.

Another interesting find would be this sea anemone. It looks like the Leather Anemone (Heteractis crispa), but the tentacles are way shorter than the ones that I have seen before. Was wondering if it could be a Heteractis malu instead.

Other findings include:

A little whelk (Nassarius mitralis) scavenging for food with its long proboscis.

A Mud Creeper (Terebralia sulcata).

Clypeomorus pellucida, which was also found in the mangrove.

Toothed Topshells (Monodonta labio) are rather common on the tree trunks and rocks.

The Haddon's Carpet Anemone (Stichodactyla haddoni) which has short and sticky tentacles.

The Giant Carpet Anemone (Stichodactyla gigantea), which has slightly longer but still as sticky tentacles.

This unidentified sea anemone is rather common on Semakau, but so far we still do not know what species it is.

The tub anemone is not a true sea anemone, though closely related. It lives in a tube, which it retracts into during low tide or when threatened.

The many little Flower Crabs (Portunus pelagicus) were rather aggressive when they saw me. Their spiky claws help them to have a good grip on their prey, which are usually small fishes.

On the way back on Saturday, I saw a swimming Snapping Shrimp (Alpheus sp.)! I have seen them crawling around, but this is the first I actually see one swimming near the water surface!

As usual, we saw a few Knobbly Sea Stars (Protoreaster nodosus) - the highlights of most of our guided walks! Our previous surveys actually revealed that there are possibly a few hundred of them on Semakau! One of the guides actually counted more than 200 during one of our trips. I had came across several dead ones though (usually broken into pieces), so there's probably eating them on the island.

The Black Sea Cucumber (Holothuria leucospilota) is rather common on many of our southern islands, but somehow it's not commonly seen on Semakau.

And moving on to the plants...

The Beach Gardenia (Guettarda speciosa) is flowering!

Semakau has one of the largest population of the locally critically endangered Api-api Jambu (Avicennia marina). Just a quick walk by edge of one of the mangrove patches, and I already found like 10 of them!

Very abundant on the island is the Bakau (Rhizophora stylosa).

During the landfill tour today, I saw these floating structures on the sandy beach near the southern most point of the island., anchored to the substrate. Wonder what they were, though I somehow suspect it has something to do with the fish farms in the background.

Really hope that Semakau would better protected in the near future.

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