Magnificently Terumbu Semakau

We are blessed with good weather today at Terumbu Semakau. It was rather hot and sunny, very different from what I experienced yesterday at Labrador rocky shore.

The word "terumbu" describes a reef that is only visible at low tide. Hence "Terumbu Semakau" refers to a submerged reef next to Semakau Landfill. You can get a better visual idea from this image.

This is my first time visiting a submerged reef on a late afternoon and the experience is very different. The animals are so alive and difficult to photograph. Not to worry, I still managed to get some good images of the animals I saw on the reef.

The sky was very clear as we set off from Marina at Keppel Bay on a boat by Summit Marine. Alex, the owner of the boat is a very nice and friendly man whom we are very grateful to have very time we go out on an amphibious landing trip to the southern shores.

View from the lobby at Marina at Keppel Bay

On our way to location

I've only managed to photographed 2 crabs. The blue swimming crab (Thalamita sp.) and the hairy crab. There were many crabs seen but they were too active and alert. Many of the crab were out feeding on the reef.

Blue swimming crab

hairy crab

There were many fish hiding in under sponges, sargassum seaweeds and swimming about playing hide and seek with us. Many of them dart into hiding quickly while some camouflaged among plants and animals.

Some of the fish seen were chequered cardinalfish (Apogon margaritophorus), yellow-banded damsel fish (Dischistodus fasciatus), seagrass filefish (Acreichthys tomentosus).

Chequered cardinalfish

Seagrass filefish

I also saw some pretty marine slugs and flatworms.
At one location, I saw 3 black-margined nudibranch close to each other. Were they trying to mate?

Black-margined nudibranch (Glossodoris atromarginata)

Black-margined nudibranch (underside)

3 of them at one spot.

2 pretty flatworms: Fine-lined flatworm (Family Pseudocerotidae) and Persian carpet flatworm (Pseudobiceros bedfordi)

Fine-lined flatworm

Persian carpet flatworm (Underside)

Persian carpet flatworm

Ria managed to find the tiger cowrie (Cypraea tigris) at the location where it was seen during the pervious trip here. There was a request from the Raffles Museum of Biodiversity Research for a specimen of the tiger cowrie. I'm glad we found it in this trip. Sadly, the animal refuse to loosen its grip in the container for me to take a better picture of. I'll just have to make do with it in the container.

Tiger cowrie in the container

There were many magnificent anemones (Heteractis magnifica) on Terumbu Semakau and some had their body column stretched as the tide moves out. The magnificent anemones attach themselves to large boulders of dead corals or solid objects, which could of a height from the ground. When the tide goes out, the numerous tentacles on the oral disk causes the animal to fall downwards. In one of the magnificent anemones, I saw a tiny anemonefish. My guess is the tomato anemonefish (Amphiprion frenatus), looking that the dark patch after the stripe.

A huge colony of magnificent anemone

How the anemone attaches itself to the solid object

One of the magnificent anemone retracts into its body column

Can you spot the tomato anemonefish?

Here's a video of the mangificent anemone.

We also saw the fire anemone (Actinodendron sp.). The fire anemone can deliver a painful sting when touched. We should not touch any animals we are not familiar with.

Fire anemone

Ria also found a upsidedown jellyfish (Cassiopea sp.) stuck in a shallow pool. A video of the jellyfish shows how it swims in the water.

Towards the end of the trip, Kok Sheng found a fluted giant clam (Tridacnidae squamosa). A GPS reading was taken to mark the location of the giant clam.

Giant clam

Close up of the giant clam,

Throughout the trip, I saw a variety of soft and hard corals.
There were asparagus flowery soft coral (Family Nephtheidae), Long-stemmed flowery soft coral, torch anchor coral (Euphyllia glabrescens), lettuce coral (Pavona sp.), brain coral (Family Mussidae), small goniopora coral (Goniopora sp.)

Left: Asparagus flowery soft coral
Right: Long-stemmed flowery soft coral

Damaged branches of asparagus flowery soft coral?

Torch anchor coral

Yellow tiny goniopora coral

Brown tiny goniopora coral

Lettuce coral

Brain coral?

As the sun starts to set, the tide slowly starts to turn. This is an indication for us to leave the reef.

Setting sun on Terumbu Semakau

Beautiful sunset on Terumubu Semakau

While waiting for the dinghy to make a second trip to the reef to bring us back, Kok Sheng found an alicia anemone (Alicia sp.). The anemone has a beautiful name but it has nasty stings. It has pretty pink lines on its tentacles.

Alicia anemone

It was a great trip with good weather, though the return journey to the marina was rather choppy.

Today is the second day of the evening shore trips for this month. There is St. John's Island trip tomorrow and Pulau Hantu on Saturday. Hope the weather stays this good.

Other posts about this trip:

Ria Tan - Tiger on Terumby Semakau