Sunday, December 18, 2005

Rocky Shore Cleanup!

Labrador Blog's Leong Wai and myself tackled debris on the rocky shore with the help of five other volunteers including a teacher on a recce trip who joined in on the spot. NParks provided us with some sacks and we managed to clear some 200kg of trash during the low tide.

Based on our impressions (we did not really categorise or count the data), an estimated 75% of the items picked up was glass, 20% was plastic and some 5% was metal.

The full report is here: "Labrador Rocky Shore Cleanup," by N. Sivasothi. Habitatnews, 17 Dec 2005 - link


Monday, August 01, 2005

Another world

To most visitors who rarely venture further out, most of Labrador's beach would seem to be comprised of either seagrass lagoon or ugly grey rocks/rubble. But sometimes at the super low tides, the corals further away from the shore are exposed. Labrador's beach slopes at a gradient, so lower tides means a much larger area of the intertidal is exposed.

This post was a long time in the making, and a few people must be credited for their invaluable help despite being terribly busy people with other things to do. Firstly, Ria Tan of WildSingapore, who has been graciously sharing her lovely photos. Also the coral "gurus" of the NUS Marine Biology Lab for helping with the tricky IDs - Jani, TL and Z.

Ok. Now let's get down to the corals. :)

First things first. Corals....animal/vegetable/mineral?

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The answer? A bit of all 3! Or at least the hard corals are anyway. The picture above shows a hard coral, Goniopora sp..

Here's a closeup of the same coral:
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You can see some of the polyps sticking out (those are the fuzzy bits that look like flowers). That's the animal part. Corals are very simple animals, kind of like inverted jellyfish, which are essentially bags of water. Since they both have stinging cells, they are grouped together under the phylum Cnidaria, which comes from the greek word "cnidos", meaning stinging nettle. Each polyp is an individual, but most clone themselves to form a colony (ending up with the big structure you see on the beach). Some hard corals, like the mushroom corals, consist of one individual polyp.

Coral polyps are actually transparent, so why are there so many colours and forms?

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Two different types of Psammocora.

Many tiny symbiotic algae called zooxanthellae live in the tissues of coral polyps and are responsible for giving the corals their distinctive colour. In return for living space, they photosynthesise and serve as an energy source for their coral hosts. That's the vegetable part!

Hard corals also secrete a skeleton of calcium carbonate - mineral! That's what fills the space between individual polyps, and also what coral reefs are made of. The polyps live in holes in the skeleton. New polyps can grow on top of old dead skeleton and this is how corals "grow".

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Acropora and close-up.
Corals are quite hard to tell apart. They need to be cut up and stared at under the microscope. But there are some general shapes that can be use to describe corals. The most commonly seen type of Acropora is the branching form (as opposed to the Goniopora shown above that is round and kind of boulder-like). It's quite distinctive since the corallites (the skeleton of an individual polyp) are cup-shaped.

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Pocillopora and close-up.
Pocillopora is branching too.

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Goniopora and close-up.
The long-tentacled Goniopora is also quite distinct. The polyps retract into the skeleton when you touch them. I always wonder where it all fits.

This one looks like a maze:
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Platygyra and close-up.

Here's where the confusing part sets in. Most genera have many different forms.
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Many different Montipora!

Corals are really important to the animals that live in, on and around them. They form reefs that become a unique ecosystem, providing a habitat for many marine animals (fish, crabs, shrimp, echinoderms, slugs, worms, the list goes on). Think of the trees of a rainforest. Like trees, they take a really long time to grow. So the next time you walk on the intertidal, do look out for these beautiful creatures, feel free to take photographs, but treat them with care. And please do not take them home!

Monday, July 25, 2005

Frogfish on Labrador!

Wandered right to the end of the beach today, near the mouth of the monsoon drain. There are many seaweeds and a whole patch of Halophila growing there. Near the big mattress-like bags, a nice surprise awaited.

Frogfish! (Lophiocharon trisignatus) It was doing a good impression of a rock, fuzzy greenish-brown outline enabling it to blend in perfectly into its surroundings.

The spot-tailed frogfish is distinguished by the dark-margined translucent spots on its tail.

In addition, frogfishes also have...

a lure on the top of their heads attached to a fishing rod-like structure which they use to attract prey with. Lures of different species of frogfish resemble different types of food animals like worms or small shrimps.

They also have modified pectoral and anal fins which they use to "walk" on the ground.

Thanks Ria, for the photos. Was too busy trying to film the fish at the time. ;)

Sunday, July 24, 2005

People on Labrador

When there is a spring low, many groups of people can usually be found walking around on the intertidal. Wildfilms and wildlife photography enthusiasts can sometimes be found with their tons of equipment aimed determinedly at some unfortunate creature of interest.

From left: Hanpeng, Tom and Dr Chua EK.

We also saw Prof Leo Tan, who wrote the BP Seashore guidebook and co-wrote Rhythm of the Sea, THE book about Labrador's Beach. A very inspiring man, he's a fount of knowledge about the things that can be found on the intertidal (and many other things, I'll bet). I found him to be a really approachable person who liked to share interesting stories and facts about the things on the shore. I also found out later that he's the man who saved Labrador's fabulous rocky shore years back when they were planning to reclaim it.

Also on the beach were a group of SAJC students on a biology field trip. Prof Leo was happy to see them, as he'd just told me earlier that it would be good to get as many nature enthusiasts and volunteers as possible to visit the beach regularly. I guess a sense of ownership is the best way to ensure that the wealth of amazing creatures on this small strip of rocky beach is continued to be protected.

Everyone looks at something interesting that has just been found.

And it is indeed interesting! Shrimps are wonderful, colourful creatures to look at, and this is the very first time I've seen the commensal shrimp, Periclimenes brevicarpalis, on the carpet anemones at Labrador. They usually occur in pairs. This is the larger of the two, probably the female.

Other interesting things spotted were...


the striped eel-tailed catfish Plotosus lineatus which has been spotted regularly at labrador over the last few months. They seem to be growing happily, and are now about 12cm long.

The seahorses from the last visit were still hanging around the same patch of Montipora.

Many thanks to Ria Tan of Wildsingapore for sharing all the photos! :)

Thursday, June 30, 2005

Suria features Labrador Rocky Shore!

Raffles Museum Toddycats volunteer Airani S introduced the Labrador Rocky Shore on the Malay television show 647km2 on 30 Jun 2005. See the report on Habitatnews.

Wednesday, June 29, 2005

Super Low at Labrador

The Wildfilms crew visited Labrador at super low last saturday. I was unfortunately unable to join them, as we were doing a Reefwalk out at Kusu (which was pretty amazing as well, but what things I missed!). Fortunately, Ria has kindly offered to share her photographs of some of the fascinating things exposed by the -0.1m tide. All photographs in this post were taken by her. Thanks, Ria! :)

They found FIVE seahorses on Labrador.

AND a HAIRY filefish! So the hairy crabs are not the only hairy things on Labrador. Filefish, also known as leatherjackets, have skin that is quite rough to touch, hence their name (file as in nail file, I guess - but i doubt the fish themselves would make good nailfiles! :p). As you can see, this one is covered by thick black hairs. He's quite colourful underneath too, blue-green all over.

And then there's the rather unusual assortment of small slimy things (which I seldom see on Labrador)...

A flatworm.

And some slugs! I'm still trying to find out what the tiny snot-green one on the left is, but the one on the right has been spotted quite frequently all over Singapore's shores recently. Glossodoris artromarginata is pale yellow, with the distinctive frilly black margin. The gills on its back swivel back and forth in the water, appearing to rotate. When startled or when picked up by an overly curious Homo sapiens, it can withdraw its gills and rhinopores (that's the 2 black things on its head, which are used to sense food or chemical signatures in the water) into its body. How cute is that? :)

The superlow tide also revealed some lovely corals at the fringe, which are usually still covered by water. Ria got some fantastic shots of them. More will be written about them soon, so keep checking back!

Wednesday, June 08, 2005

Labrador's all time favourite crab - the hairy crab

Pilumnus vespertilio is also called the Common hairy crab or the Teddy-bear crab! And when I say favourite, I mean as in personality and not palatability, so stop salivating.

Unlike the vicious swimming crabs or teh aggressive grapsids and the feeling rock crabs, the hairy crab seems to be the most gentle-natured of all the crabs in Labrador and our favourite!

After some initial efforts to move away, it will eventually rest in your palm, usually evicting squeals of "how sweet" from visitors to Labrador.

It is not a good idea to think of eating this small crab since other than seaweed, it may eat toxic zoanthids (colonial anemones) which can make this crab mildly poisonous.

It looks hairy because the body is covered by long hairs. These are slightly suspended when submerged in water and trap sediments, allowing the crab to blend into its surroundings by breaking the body outline.

It is slow moving and rarely seen unless you know where to look - under rocks in a specific zone along the shoreline. Yueat Tin had a look last month (May 2005) and took this photo.

Airani will be bringing the crew of the Malay magazine programme 647 to Labrador tomorow (09 Jun 2005) and promised to show them her favourite crab, the teddy-bear crab, so its going to get famous!

Monday, May 16, 2005

Dolphin carcass on Labrador beach

See "Indo-Pacific humpbacked dolphin carcass on Labrador Beach," by N. Sivasothi. Habitatnews, 15 Jun 2005 - link

Wednesday, April 13, 2005

Morning visit

Finally, a chance to visit again after a long hiatus. The posts were a lovely read in the meantime. :)

The water at Labrador has been amazing lately. At low tide, just a bit higher up from the choppy waves near the corals, it's so nice and clear, even walking around chasing a pack of camera-shy catfish doesn't seem to muck it up much.

Juvenile striped eel-tailed catfish (Plotosus lineatus) - if you look closely you might even be able to see the barbels!

Near the rocks, an octopus was spotted trying to eat a swimming crab. When we found him, the poor crab was still moving. The octopus was mostly inside his hole, except for tentacles sticking out, but for a moment his eyes and siphon were clearly visible as he tried to consume the crab, which proved to be a bit big to drag into the hole. Unfortunately he spotted us peering at him and decided to retreat behind his half eaten meal.

Octopus hiding under breakfast. Can you spot the sucker discs of the octopus?

Another crab, this time alive. The red egg crabs are quite common on Labrador, found around the corals where the water is a bit deeper and usually quite choppy.

Red Egg Crab (Atergatis integerrimus)

The colonial anemones have been back since my last few visits. They are of all colours and cover certain areas of the beach. Really beautiful to look at. But not to touch. Anemones are stuck in the same group as jellyfish and coral. They are called cnidarians because they have stinging cells which can leave a painful sting! I'm surprised there haven't been photos of these amazing creatures around.

Pretty brown ones. Quite hard to photograph due to moving water surface.

And the solitary anemones which seem to be quite commonly found on Labrador as well. This one looks a bit different from the usual ones spotted..

Quite strange. No one seems to know what they for the moment, unknown anemone.

Tuesday, April 12, 2005

concrete beach

think there's nothing on the seawall? look closer...


seaslugs (They're well camouflaged. At least 5 of them in this pic)

mermaid's fan (padina)

you'll be surprised to find species that are seldom found on the natural shore on the seawall instead. The star limpet is one of them. These guys are 3 times bigger than a normal false limpet.

With more areas becoming urbanized, natural shores are rapidly replaced by artificial structures (If you can find old pictures of labrador beach, you'll see that the park and seawall replaced a part of the natural beach). These structures have the potential to affect the biodiversity of intertidal environments and it may be worth your time to take a walk along the seawall and compare what you can find there (there are more species than those shown above) as compared to the natural beach.

working late has its rewards...

tread lightly and you'll realise the best things are for free
let the sea breeze caress your hair, makes you feel carefree
standstill and listen to the music of the sea
let the waves around your ankels cool your tired feet
the sky changes colours and golden rays retreat
you'll be sad to leave but good memories are yours to keep