The Story of Shells – Part 2

Disclaimer: Opinions are mine.

Satellite imagery between 2012 and 2015 had led to the exposé of widespread dredging of fossilised giant clam shells in the South China Sea. The distinct arc shapes, visible from space, were the result of boats chopping along the reefs. What was even more surprising is that this was done to reveal the buried giant clam shells!


My curiosity brought me to Tanmen Village, and I shared my story through a photo-essay earlier this month, and published it here. Now that you have seen the industry through my eyes, I wanted to provide the contextual insights of the Chinese cultural history, industry and how businesses have bloomed since the introduction of giant clam shells as materials.

Advisory: This is a 15 min read.

1. Significance of Giant Clams (硨磲贝) in Chinese’s cultures

Culture or ‘the way of life’ usually plays a big role in influencing people’s habits and mindsets. Whether they are a fisherman, a craftsman, a farmer, or a religious priest, their actions are mostly driven by their cultural beliefs and hand-me-down stories. It was a similar situation for the giant clams and the Chinese’s lifestyle.

During my walkabouts in Tanmen Village, I’ve learnt several interesting details on what the Chinese thought of the giant clams:

  • Giant clams are one of  China’s treasures
  • Considered a rare organic gem (有机宝石) that is produced by animals – the purest of white ‘jade’
  • At times, they are referred to as the ‘jades of the sea’
  • Has been mentioned as one of the seven treasures in Buddhism
  • Believed that it can help ward off evil and protect the health of families based on its supposed healing properties
  • People are aware that giant clams are nationally protected species (国家一级保护动物), thus making them even more highly valuable!

Okay, so my initial conclusion was that this appears to be one of the typical beliefs that the animals had special properties to aid with health issues (something like the rhino’s horn, tiger’s penises, and seahorses). And the other facts were to stimulate the demands and sale of giant clams in China – a marketing strategy.

Or so, I thought! Later in my exploration of the shops, I found this book entitled “National Treasures – Giant Clams” by Li Heng, a Hainanese-based writer whose interests is to promote the cultural heritage of Hainan Island. On the front cover, it also says that this book is the first of its kind to discuss extensively on giant clams in China.

THIS WAS A TREASURE FOR ME! Imagine my excitement when I ‘accidentally’ came across this book! I was glad that I’ve left no stones unturned, and what I read what absolutely compelling. 😀


It seems like the giant clams go wayyyyyyy back in Ancient China (most conclusively present in the Qing Dynasty)! As a child, I loved watching the ancient Chinese dramas, where the court officials have their ‘furry hats’ on, beaded necklaces, and embellished overalls. NOW I know that the beaded ornaments were made from giant clam shells! It was also mentioned that because gold was common in ancient times, the giant clam shells cost a lot more than gold!

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2. Valuing Giant Clams

Shells from Scarborough Shoal were considered of highest grade

I was told by the shops that their shells came from three areas in the South China Sea, and the quality of shells decreases in the following order:

  • The Scarborough Shoal (黄岩岛): Considered the best shell grade because they are uniquely colourful (red, purple, brown, yellow, green, white), and their shells are dense and least brittle. Due to the rarity of shells from the geographic locality, they are highly prized.
  • Spratlys (南沙群岛): Ranks behind those found at Scarborough Shoal, but comes in fewer colours (mainly yellow, brown, white), moderately dense but brittle. Most carving products in the market are made from shells in the Spratlys.
  • Paracels (西沙群岛): The least favoured but abundance of materials. Few colours (mainly yellow, white), and tends to be most brittle of the three. Not suitable for large carvings, and generally mass produced as white beads.

Pricing the products based on colours, translucency, and perfect cuts

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Table 1. Shell handicrafts were generally priced based on the rarity of colours, translucency, and lack of defects/cracks.

While the origins of shells matters to the craftsman (as it determines the type of handicrafts produced), the products across the various shops were priced quite similarly based on Table 1. For instance, the costs for the same 108-Buddhist beads made with the colourful Scarborough Shoal shells versus the plain-looking Spratlys shells could differ by 50 times (in the Chinese currency, Renminbi)!

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Giant clam-shell based products are hard to counterfeit

To understand why the locals treasured handicrafts made from giant clam shells, I found myself relating my observations to the biophysical properties of giant clam shells. Here are some reasons:

  • Good quality shells are hard to come by, and in this case, those found at Scarborough Shoal.
  • Every product made from the giant clam shells are unique and one of its kind.
  • They are difficult to counterfeit.

As a young tiny larvae, giant clams are builders. They build their own shells by making aragonite – an alternate form of calcium carbonate. This shell-making process may be affected by the reef environment they live in, for example, the availability of light, nitrogen, or carbon can determine how well they build their shells. To add on, each giant clam is distinctive with their own pace of constructing shells – some individuals may grow very fast, making thinner but bigger shells, while others grow slower, making thicker but smaller shells. Lastly, similar to tree rings, the shell growth pattern of giant clams resemble ‘rings’ – representing days, weeks, or years!

Watanabe et al., 2004
Figure from Watanabe et al. (2004) Palaeo 212: 343-354. (a) Tridacna gigas shell from Kume Island, Japan. (b) Optical transmitted-light photograph of the inner shell layer of T. gigas. Dashed lines represents sampling transect for isotopic measurements.

3. Businesses As Usual? (accurate as of 11-12 August 2016)

After my ground surveys, I mapped out my thoughts and this Figure 1 summarises the simplified version of the various businesses.

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Figure 1. Mapping out the connections and activities of the giant clam shell business in Tanmen Village.

Business Players Big and Small

The major business players are those with processing factories and warehouses. When I spoke with the owners of these businesses, I found that they have been selling giant clam handicrafts for >10 years, and bought their shells from specialised giant clam fishing boats. By late 2016, where many clam fishing boats have ceased activities, one of the owner boasted to me that they have enough stocks of shells to last them another 10 years of business. She didn’t mention whether their warehouses were nearby, but I believed her words based on what I saw…

The small-time businesses, on the other hand, are not coping too well with their sales. They tend to buy the handicrafts from wholesale, but one man said that business was poor and prices were lower. He has tried his hand to sell online, but hard to compete with the cheaper fakes. They were also very nervous because authorities were beginning to confiscate the products.

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Humans of Giant Clams

I met an owner, who previously specialised in carving ornamental jade for almost 10 years. As the market for jade products became saturated causing their prices and popularity to drop, he was looking for alternative materials for handicrafts. Then in 2012, he began to use giant clam shells and have not looked back since. Clam shells became increasingly popular among craftsman, and many started to buy large quantities from the clam fishing boats. He even told me that several Singaporeans had visited him to buy his products in bulk! :O

Another person was a master craftsman with >20 years of carving experience. He had started with jade too, but decided to move his family from mainland China to Tanmen Village to start a wholesale business on the giant clam shell handicrafts – seizing onto the golden opportunities. As I browsed his humble workshop, his wife and himself were beaming with pride and excitement at the prospects of this new business. One that brings in more wealth to improve their living standards.

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4. My personal notes

I was sad.

I was sad to see the massive piles of giant clam shells in the backyards of factories, hidden from sight.

I was sad as I realised that giant clams used to be this plentiful in the South China Sea.

I was sad because I felt conflicted between my role to be an objective scientist and to feel emotionally connected with the locals’ livelihoods.

But I was also very glad to have gone through this investigation and seeing the trade unfold.

With such a long traditional history of using giant clam shells as ornaments in China, we risk the loss of an important part of human history. By encouraging the trade, we risk the loss of more giant clams, as well as the destruction of coral reefs in its path. I see the problem, and that is the demand for giant clam shells had led to widespread mining of the seabed for them, and in the process also led to massive destruction of coral reefs.

I don’t think I’ll know where to begin solving this complex problem, and I don’t have any answers for you. Maybe you’re thinking, “After reading your story, and you tell me there’s nothing we can do???” Wait a minute! Give me a chance to leave my alternate ending remarks! 😉

I do know (and hope that you feel the same way) that from experiences like this, I am learning to be more compassionate towards issues that science alone cannot solve the world’s problems. As a close friend told me, “If science had been the solution for all the world’s problems, why are we still having this conversation now?” I just laughed and nodded…



What’s in the Lab?

Not too long ago, I was studying shrimps. 🙂

No no, I did not forget my first love, the giant clams. It was purely coincidental when my colleagues and I came across a pair of shrimps latched onto the giant clam’s gills (or respiratory organs). Based on our earlier literature review on ‘The ecological significance of giant clams in coral reef ecosystems‘, we knew that giant clams hosted shrimps in a relationship known as commensalism.

Commensalism refers to the association between two organisms in which one benefits and the other derives neither benefit nor harm. In this case between the giant clams and shrimps, we think that the shrimps likely had more to gain from living inside the body of a big ‘bodyguard’ and pinching food off from the gills of the clams. Some scientists suggested that the shrimps may cause some harm to the clam host by nipping off tissues from its gills, but this is anecdotal.

Figure 1. A pair of Anchistus miersi shrimps collected from a fluted giant clam, Tridacna squamosa. a) Male shrimp and b) Female shrimp.

We consulted the experts and the shrimps were both identified as Anchistus miersi, and they were a male-female pairing (Fig. 1). The male (Fig. 1a) tends to be smaller than its female counterpart, and the female (Fig. 1b) was brooding eggs (in pale green).

The most interesting observation here was that the same species of shrimps exhibited different spot colours within a single population (found in a single giant clam)! Here, when alive, we observed that the male shrimp had red dots and the female shrimp had blue dots. Upon preservation in ethanol, both specimens revealed a mixture of red and blue pigments. We concluded that the species, Anchistus miersi exhibit dichromatism.

Dichromatism means the occurrence of two different colours in animals. So why do they exhibit dichromatism in the same species? We simply have no idea yet! There are no obvious advantage or disadvantage being colourful as they live inside the clam host for their entire lives. The simultaneous occurrence of red and blue pigments does suggest that the colour pattern is not fixed.

So can the shrimps change their spots? Even more questions!


  • Neo, ML, BY Lee, K Vicentuan & PA Todd (2015) Dichromatism in the commensal shrimp, Anchistus miersi (De Man, 1888). Marine Biodiversity 45: 877-878.


I just popped a GIANT paper!

After an incubation period of almost 3.5 years long, I’m a proud ‘mom’ of this new OpenAccess publication 🙂

Neo et al. (2017) Chapter 4. Giant Clams (Bivalvia: Cardiidae: Tridacninae): A Comprehensive Update of Species and Their Distribution, Current Threats and Conservation Status. Oceanography and Marine Biology – An Annual Review. Volume 55. Pp. 87-388.

What started out as a desire to produce an erratum for an earlier review paper has turned into a monster paper (301 pages)! Throughout the process, I felt like a detective – spending hours mulling over every piece of evidence, and snowballing my clues from paper to paper. I spoke to people via emails, and anyone who would give me an inkling of ‘where can I find giant clams?’ I trawled through thousands of photographs and identified each one of them to species. At the end of my compilation, I needed the other experts to verify my findings and I’m so very thankful for their utmost contribution and commitment. Without my precious collaborators, this work would not have been the most solid foundation for advancing knowledge on the giant clams.

From here on, I hope that our paper will serve its purpose and help many other scientists, managers, and public members to view these amazing animals through my lenses. 😀

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The Story of Shells – Part 1

Disclaimer: Opinions are mine.

‘South China Sea’ and ‘Giant clams’ are possibly two key phrases that have been connected on many occasions in just 2016 alone. Some of you may have read how the widespread poaching of giant clam shells in the South China Sea caused the wipeout and massive destruction of reefs.

Almost exactly one year ago, on 30 November 2016, the Hainan Province had decided to amend their existing ‘Republic of China Marine Environment Protection Act’ and the ‘Republic of China Wild Animal Protection Act’ to include both coral reefs and giant clams. This also meant a province-wide ban on the sale of corals and giant clams beginning on 1 January 2017. Although ground observations pointed out that the sale of giant clams has always been illegal with weak enforcement.

Beyond the borders of Hainan Province, authorities on mainland China have intercepted a shipment of giant clam products, reported in September 2017. The brief article pointed out that ‘giant clams listed as a Class I state-protected animal in China’ – also learning that the pandas are listed on this same category! What a vast difference in ‘protection levels’ between them!

My interest in this subject matter began when my colleagues from the Centre for International Law (NUS) invited me to discuss about topographic features of South China Sea (i.e. mapping of reefs). I began to do some research on my own about the shells and industry, with the help of my senior mentors such as Professor Ed Gomez.

There were plenty of information from both the English- and Chinese-based media, and I saw a problem. I realised that the majority of readers have formed a (very) negative image of the Chinese and blamed them for what happened in the South China Sea and the giant clams. Lucky for me, I can read English and Chinese (yes, in Singapore, we learn two languages as kids!), my colleague and I read lengthy forum posts on how there were many Chinese people (and scientists) who were equally outraged by what was done in the South China Sea and the giant clams.

And so, I decided to make my way to see the famous ‘giant clam’ village for myself. This trip would not have been possible if it were not for my gung-ho collaborator and guide. What you will see here on is my photo-essay of the two-day trip in August 2016 to Tanmen Fishing Port on Hainan Island, just a few months before the announcement of the sale ban. [P.S: I did felt like a detective snooping around! 😛 ]

This is my story of the giant clams in the South China Sea…

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This simple monument marks the entrance to the Tanmen Centre Fishing Port.

The weather was dry and warm. Then again, Hainan’s weather does not get very cold even during winter season. My companion and I arrived in Boao (博鳌镇), which is approximately 10 km to our intended destination – Tanmen (谭门镇). I remembered feeling very nervous and jumpy because we met with difficulties in getting transport into the town, and we were constantly being ‘cheated’ of our fares. I remembered also feeling excited at the prospects of what I would see first-hand in this town.

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A traditional fishing town, this is the fishing vessel used for long-range fishing in the South China Sea. The light bulbs on the second deck are iconic features of these vessels. This vessel specifically flies the Chinese Flag State.

Tanmen fishing port is the largest fishing port on Hainan Island, as rated by China’s National Agriculture Bureau. It is also a distribution centre of marine products in Hainan. As we walked along the pavement next to the mouth of the sea, we saw the fishing boats lining the port – no signs of fishing. I later found out that there is a mandatory annual fishing ban between April/May to October in the South China Sea to allow for recovery of fish stocks. The fishermen would go fishing in the South China Sea, which is a very long way from home. Often, they would have to live on their boat for almost a month long before returning home with their catch.

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Photographs here depicting the old looks of Tanmen Bay, which includes fishing and aquaculture-like facilities.

Flabbergasted is a word that I would not use lightly but it is appropriate for what I am about to describe. We saw streets after streets of shops filled with nothing but handicrafts made of giant clam shells. It was said that the rise of the giant clam handicraft industry also saw the number of retailers increased from 15 in 2012 to a whooping 460 in 2015. By 2015, this industry was supporting nearly 100,000 people, according to estimates.

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Today, the town has transformed into a shopping district with consecutive shops selling giant clam shell handicrafts and jewelry.

We popped into a few retailers and began to converse with them about the industry – how and when they had started their businesses, and to hear pride in their voices when talking about these Hainan giant clams. It was like the ‘gold rush’, only that this was a ‘clam rush’. 🙂 As I was browsing their products, I was also admiring the craftsmanship that was put into each item. Many of these products reflect the strong and rich history of Chinese cultures, and are symbols of wealth, health, luck, and prosperity. They are also attractive as display ornaments.

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Retailers taking different marketing approach to attract clients. The text says, in brief, that giant clams, a precious organic gem, are considered one of the seven treasures in the Buddhist scriptures ‘Jin Gang Jing’. It has calming powers, and also used for praying purposes.
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Intricate carvings that still resemble the giant clam shells, portraying typical icons of religion (L) or scenes from ancient China (R).
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Giant clam shells are ‘graded’ based on its location, colours, and translucency. The ‘blood-red giant clam’ (top L) was most valuable, followed by purple, orange, dull green, yellow, and white. Buddhist prayer 108-beads (top R) and large carvings (bottom) are examples of handicrafts.
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Retailers also show their prized craftsmanship that are not for sale, but demonstrates the quality of their products. Here shows the Goddess of Mercy that won the Silver Prize for China’s Jade Stone Carving Award with certification.
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The 18 Arhats (十八罗汉) depicted in carvings on giant clam shells were intricate, exquisite and expensive. They are the original followers of Buddha, and are charged to protect the Buddhist faith. In China, the 18 arhats are a popular subject in Buddhist art.
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Various animal lucky charms, from Arowana fish and frogs to imitating elephant ivory tusks. All symbols are iconic to the Chinese culture and beliefs of affluence and luck.
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Top: Apart from the Tridacna species of giant clams, I also found Hippopus species on display. Bottom: The lowest grade and quality of giant clam shells (white and opaque) are rapidly transformed into beads for wholesale distribution. The room was filled to the brim with bags and bags of threaded beads waiting for buyers.
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Spying the cabinets, I found coral skeletons also being used to make pendants. It’s hard not to miss the unique corallite shape. Retailer says that they are not as popular as those made from giant clams.
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Business appeared slow. This shop was closed for holiday, and used cardboards to cover their products. I was unsure why the need to cover their products, but heard that authorities were slowly clamping down on businesses.
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Jack of all trades – these retailers selling bicycle parts and strings of beads made from giant clam shells.
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Like breadcrumbs, we followed the trail of broken beads along the beach. It was clear that these beads did not make the cut to be put on the shelves.

By the fourth retailer, I was already exhausted. The shops began to look very similar to each other. The shops were selling very similar items. My companion and I then wandered off the fancy streets and into the housing areas. There, something caught my eye – the trails of broken white beads. As I followed them like breadcrumbs, they led me to a huge puddle of them laying abandoned. Eventually, we were standing in front of a warehouse that was surrounded by piles of fossilised giant clam shells. They were covered with sheets, seemingly trying to hide from view. We were shortly ‘chased away’ by the foreman…

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The beads led us to this massive stockpile of yet-to-be processed giant clam shells that appear to stretch for forever.
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Capturing behind the scenes in a small processing factory.
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Given the hardness of these shells, I found an angle grinder used to cut them into smaller pieces for carving and moulding.

To have this opportunity to speak and meet the people driving the industry was insightful for me. Admittedly, the methods used to harvest these raw materials was harmful and destructive to the environment in the South China Sea, but the industry became an important element supporting the livelihoods of people living in Tanmen. This is a conservation dilemma…

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A crafts master shared with me that he only carves white cabbages (白菜), which symbolises wealth and prosperity.
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Not just hand-made, some of the items were created using computerised printing. It reminded me of the 3D printer.
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The living were not spared. I found the shells of freshly poached giant clams and hard corals hidden in a dark room. The clean inner surfaces of shells and lacking thickness suggest that they were recently dead. In most instances, the fossilised giant clam shells rarely come intact and with complete paired shell valves.

From a scientific point of view, it was a good opportunity to have been on the ground and surveying the industry. It was exciting to pose as a potential buyer and talk to the locals to find out more about the products and what made them so proud of their giant clams. It was sad to see the vast numbers of giant clam shells on the streets and in the factories. It was interesting to observe these raw materials first-hand and how they were transformed into beautiful pieces of articles.

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The limited source of ‘blood-red’ giant clam makes them highly sought-after and valuable to retailers and buyers. 
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Trapped Hippopus spp. shells in crates.
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We wandered into a medium-sized factory and stumbled upon even more piles of raw materials: fossilised giant clam shells. I can only imagine the sheer number of giant clams that once lived in the South China Sea that were first harvested as food and now for their shells.
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These shells were dredged up from the bottom of seabed and coral reefs in the South China Sea. In the process, this destroyed large areas of coral reefs.
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Semi-processed shells comprising at least four species of giant clams: Hippopus hippopus, Hippopus porcellanus, Tridacna derasa, and Tridacna gigas.
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Corals under cover.
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An advertisement board sharing the cultural value of giant clams. A unique aspect was the comparison with western culture using the Birth of Venus.
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The China’s president famous visit to Tanmen Port in 2013 that was said to have spurred the fishing exploits to the South China Sea.

This is the first part of my insights of the industry. Stay tune for Part 2 of my story that will elaborate why these giant clam shells are significant in the Chinese cultures, the value and quality of giant clam-based products, and interview bits and blobs with the local crafts masters and shop owners.

What’s in the Lab?

Some years ago *ahem 10 years*, my classmates and I had to produce a video to showcase animal behaviour for an undergraduate class assignment. Of course, we decided to do one on the giant clams! 🙂

Unknown to many, giant clams do exhibit a wide variety of behaviour as presented in this paper by Soo & Todd – The behaviour of giant clams. One of the most interesting behaviour for me is watching the little clams walk around! Yes, they can walk!

In order to find out how fast they walk, we set up an experiment in an aquarium tank. We laid grids to help us measure the distances moved by the clams at the end of experiment. We first arranged the baby clams neatly in rows and columns, and later remotely monitored their ‘movement’ using web-cam and infra-red cameras over 24 hours. These pictures showed the before and after of experiments, and we can see that the clams messed up our arrangement!

Soo & Todd 2012 Results
Extracted from Soo & Todd (2014).

If you like to read up more about how and why they are motivated to go walking around, I have an older post on “Why did the giant clam cross the road?” Also, do watch this video on how we conducted the experiment. We definitely had plenty of fun designing and setting up this experiment. Enjoy! 😀

TED Talk – The fascinating secret lives of giant clams


Again, I like to thank the many individuals mentioned here for making this dream happen. Now, giant clams – show the world what you got! 😉

You can watch it here:

For more information about the conservation work on giant clams, you may read them in the various posts titled “Conservation of giant clams – Parts 1, 2, 3, 4“.


Field work – Bachok Marine Research Station (11-16 June 2017)

First and foremost, thank you to my collaborators, Professor LIM Po Teen, Dr LEAW Chui Pin, and Professor Aileen TAN, as well as the Malaysia Marine Park for supporting our field research to survey the giant clam populations in the Perhentian Islands, Terengganu! Also, thanks to L’Oréal Singapore For Women in Science National Fellowship for supporting my research! 🙂

Field sampling for giant clam tissues to examine the population genetic structure in Perhentian Islands. Credits: Lim Zhen Fei.

Continue reading “Field work – Bachok Marine Research Station (11-16 June 2017)”

TEDxSingapore Salon Event

TEDxSingapore Salon Event – 20 May 2017. Credits: TEDxSingapore FaceBook page.

Throwback to TEDxSingapore Salon Event last month at Collision 8! It was their first ever live broadcast via FaceBook Live! In this interview, I shared my first time experience at TED2017, my journey as a TED Fellow, and my work life as a marine biologist. You can catch my interview with Gillian (TEDxSingapore curator) by clicking on the video below! 🙂

Post-TED gratitude – It’s ‘not’ a Clamity!

Speaking at TED in Vancouver, Canada (April 2017). Photo by Ryan Lash / TED.

It’s been almost 20 days since I had stood on the TED stage and gave one of my best talks so far (I kid you not!). Now that I have given my talk, I had spent the last 20 days thinking about my experience as a TED Fellow in the programme, and how meeting other Fellows has helped me figure out some things in my life.

Continue reading “Post-TED gratitude – It’s ‘not’ a Clamity!”

Conservation of Giant Clams – Part 4

Today’s the DAY! And by the time you read this post, I should be getting ready to give my TED talk at the conference! 😀 In my 5-minute comprehensive TED talk, my idea worth sharing is that giant clams are ecologically important to coral reefs, and we need to save them! For my final part, I will describe the numerous Ecological Roles that giant clams play on the coral reefs, and why we should care about conserving them!


Continue reading “Conservation of Giant Clams – Part 4”