Sunday, November 18, 2012

Stormy Trip to Hantu Lagoon

It was a scary day for fieldtrip. Constant checking with the NEA's weather animation since afternoon shows a huge scary cloud mass heading down south.
On the boat ride, the animation on NEA's website shows a very scary angry cloud covering the western part of Singapore. Even Pulau Hantu was covered. At the pier, we were showered with the fierce blowing rain while waiting for passengers in the boat to alight.
From google map, Pulau Hantu is located on the south-west after Pulau Bukom. The whole Hantu Island is form by two islets: Pulau Hantu Besar (Big Ghost Island) and Pulau Hantu Kechil (Little Ghost Island). Hantu Besar is located on the West and Kechil on the East of the island. In between Hantu Besar and Kechil is the big Hantu lagoon.

Apart from the yearly intertidal checks done a team of shore explorers, the Hantu Bloggers conduct regular dive session on the reefs of Hantu.  Regular updates on the reef health can be seen through their website.

The Hantu Kechil jetty lies in front of the Southern coastline of Pulau Bukom. In the low light, heavy rain, bright lightnings and loud thunder, the infrastructures on Bukom Island are lit with lights that looks like Christmas lights.
Background: Pulau Bukom
Foreground: Pulau Hantu Kechil Jetty
The heavy rain has caused serious murking in the water on the reef area that  is densely covered with sargassum seaweed. It is not safe to walk in such murky water as mr. stonefish can be hiding anywhere.
Murky water on the reef.
The rain and lightning carried on for quite some time into the evening. I spent half the time walking around the shore looking at animals as my cameras were not weather proof. Majority of the photos here are taken in the later half of the trip, when the rain had died down. During this period, I helped to collect 3 samples of snapping shrimps. Despite the storm, there were many exciting things to be seen in the reef.

While walk down from the jetty to the shore, there were a few young mangrove plants rooted on the high shore and there were already leaves growing.
Young mangrove plant
There were many common sea stars (Archaster typicus) everywhere in the lagoon. Some of them were alone, some were in pseudocopulation position. You can read about pseudocopulation position of sea stars in The Echinoblog. As mention in the blog, the pseudocopulation position allows maximised fertilisation during the mating process. Most of the time, we simply refer such position as the mating position.
Top view
Underside view reveals the stomach sticking out through its mouth
Pseudocopulation position
There were many patches of tape seagrass and the coverage of the seagrass is average of at least 50-60 cm. I noticed that the tape seagrass (Enhalus acoroides) were about 40% covered with epiphytes and mostly tiny hermit crabs were found on the seagrass. I'm practicing my seagrass monitoring skills here. Hahaha...

On one patch of tape seagrass, I found a starry flatworm (Pseudobiceros stellae) moving on a grass blade.
Starry flatworm
A small three-spined toadfish (Batrachomoeus trispinosus) was seen lying motionless in a shallow pool, next to come rubble.
Overview of the toadfish
Closeup near its head
Other fish seen includes gobies, spangled emperor (Lethrinus nebulosus), plain halfbeak and many other small fish that were too fast for me to notice any features.
Spangled emperor
Closeup of the spangled emperor
Marcus found a polka-dot nudibranch (Jorunna funebris).
Polka-dot nudibranch
Feathery gills
Chay Hoon found a seagrass sea hare (Phyllaplysia sp.) and a small gymnodoris nudibranch (Gymnodoris sp.). The sea hare blends in so well on the tape seagrass that anyone would have missed it easily if we do not spent enough time looking at the seagrass. While taking photos of the seagrass sea hare, I found a even smaller seagrass sea hare moving behind the bigger sea hare.
Seagrass sea hare
Smaller seagrass sea hare following behind
Gymnodoris nudibranch
The best finding for me in this trip would be a tiger-tailed seahorse (Hippocampus comes). It is so funny that I could not find the seahorse when I kept searching for it and when I was focus on looking at some other animal, the seahorse appeared.
Side view, showing details on its head
An attempt to get a good profile of the seahorse
Here's a video of the seahorse.

Nicole found a hyperactive cuttlefish, which we took quite some time to get it to stay still. Eventually, it settled down near by booties as seen in this video.

In the reefy area, I only see one giant carpet anemone (Stichodactyla gigantea). Suspicious movement on the tentacles indicates the presence of the false clown anemonefish (Amphiprion ocellaris) and there were at least 3 of them in this giant anemone.
Only body seen
Only tail seen
Back at the lagoon area in front of the jetty, Ivan found an octopus and he tried to coax the octopus into moving to deeper water but it refuses to move. Instead, it kept spouting water. Here's a series of the octopus spouting water.
No water
Some water
A jet of water
Alas, I found two crab traps placed in the lagoon. By the look of the chicken feet in the trap as bait, the traps was place in the lagoon probably earlier in the day. The second trap I found already had a flower crab in it. I cut the net to free the crab and removed both traps.
Trap 1
Trap 2
Flower crab in trap 2
two traps gathered
Chicken feet as bait
Other than close lightning strikes, nothing else can stop us from going down to the intertidal reefs to check out the marine life.

That's the end of the evening trips for this month. December is going to be a very busy month for me with work attachments at Raffles Museum of Biodiversity Research and my advance diving course at Lembeh Resort. Wait... I am suppose to be on school holiday like my students.
Well... anything involving marine biodiversity excites me!

More posts about this trip:
Ria Tan - Night of 'Nemos' at Pulau Hantu

Saturday, November 17, 2012

Fishy and Sluggy Day at St. John's Island

Oh no.... As we landed on St. John's Island via private ferry service, we could see a fierce storm covering the skies of mainland Singapore.
Look at the cloud formation on mainland.
While round a corner of the island, the sky shows some of the pretty orange sunset with the fast moving storm clouds.
Sunset and storm clouds
St. John's Island is one of the many southern islands in Singapore. It was previously known as Pulau Sekijang Bendara or "deer flag". St. John's Island now houses the Tropical Marine Science Institute (TMSI) and AVA's Marine Aquaculture Centre (MAC) for marine research and development. There are also chalets available, managed by Sentosa, for public who wish to stay over on the island.  The Singapore Island Cruise provides ferry services to some of the southern islands with a fixed ferry schedule. You can also read more about the history of St. John's Island from the National Library Board's Infopedia.

Light rain started to fall shortly after the team began exploring the shore. However that did not stop us as we wore our ponchos or opened umbrellas and continued our work. The thick sargassum seaweeds in the rain means we have to be extra careful when walking around in shallow waters to avoid stepping on mr. stonefish.

I got my first find from Chay Hoon, an extraordinary sea hare (Aplysia extraordinaria)
Extraordinary sea hare
Chay Hoon also found a spotted-tail frogfish (Lophiocharon trisignatus). This is my first time seeing a frogfish in Singapore waters and also on intertidal trips. Exciting!
Top view of the frogfish
The frogfish gives a stunned face when out of water
Nearby, there was a dawn flatworm (Pseudobiceros uniarborensis). It has an orange edge.
Dawn flatworm
Also, an empty ovum cowrie (Cypraea ovum) was found.
Top view of the ovum cowrie
Underside view of the ovum cowrie, showing the "teeths"
Unfortunately, with my slippery fingers, the cowrie was flicked into the rubbles while I was trying to wash it and I could not find it again.

I caught my first octopus, thinking that it was some special octopus but later released it as it was a common octopus we always find on our shores.
 With the sargassum seaweed bloom and shallow waters, many fish could be seen in the dark easily. There were chequered cardinalfish (Apogon margaritophorus), false scorpionfish (Centrogenys vaigiensis), gobies, plenty of filefish (Family Monacanthidae) and many other types of fish.
Chequered cardinalfish
Cardinalfish, goby and an ocean strider
False scorpionfish
Carpet eel-blenny (Congrogadus subducens)?
Other sea slug seen include the hairy sea hare (Bursatella leachii).
Hairy sea hare
We also had a special find in the lagoon, the moon-headed sidegill slug (Euselenops luniceps).
Back view
Top view
Underside view
Side view, with visible gills
I only saw one giant carpet anemone (Stichodactyla gigantea) and a lonely five-spot anemone shrimp (Periclimenes brevicarpalis). Not very sure where the shrimp's partner went to. This shrimp is usually seen in a pair on the giant carpet anemone.
Giant carpet anemone
Five-spot anemone shrimp
At the corner area of the island, I saw codium green seaweed (Codium sp.) and zebra coral (Oulastrea crispata)
Codium green seaweed
Zebra coral
Over at the lagoon, there were more exciting findings.
The horn-eyed ghost crabs (Ocypode ceratophthalmus) were very active and out on the shore. Ria saw one eating a fish as big as itself.
Horn-eyed ghost crab trying to hide in the shallow water
Close up of the crab
Crab eating a fish
Photo by Ria Tan
There were a number of black-lipped conch snails (Strombus urceus).
Underside of the conch
Top view of the conch
There were also many small common sea stars (Archaster typicus) in the lagoon. Look at the size of the sea star as compared to the snails nearby.
Top view of the sea star
Underside of the sea star
The happiest happy I saw would be the solitary tubeworm (Diopatra sp.). It has beautiful feathery appendages (branchiae with spiraled filaments around the central stem).  I had my first encounter with this worm during the recent Comprehensive Marine Biodiversity Survey Northern Shore Expedition. Arthur Anker has great photo of this beautiful worm I collect during the expedition.
Coming out of its tube
Showing its pretty feathery appendages
Reaching out to grab something
Diopatra sp (Onuphidae)
Photo by Arther Anker
The oddest find in the lagoon would be the shell of a garden snail.
Top view
Underside view
It was a great day on the reef of St. John's Island despite the passing rain.
Tomorrow will be our final trip for this month, to Pulau Hantu.

More posts about this trip:
Ria Tan - Sluggy on St. John's Island


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