Skip to main content



Hidden sentinels who guard Singapore’s biodiversity

SINGAPORE — On a regular dive trip to Pulau Hantu, all her friends were excited about seeing a dirty-green frogfish for the first time, but Ms Toh Chay Hoon just could not spot the 12cm-long ambush predator no matter how hard she tried.

SINGAPORE — On a regular dive trip to Pulau Hantu, all her friends were excited about seeing a dirty-green frogfish for the first time, but Ms Toh Chay Hoon just could not spot the 12cm-long ambush predator no matter how hard she tried.

Her friends had to point it out to her eventually.

The 40-year-old senior executive’s eye for minute marine creatures though, has stood her in good stead as a volunteer with the National Parks Board (NParks): She has discovered a new species of coral mimic crab and about 10 new records of sea slugs in Singapore’s waters over the years.

The 0.4cm cream-coloured spotted crab, which she accidentally discovered while on the lookout for sea slugs, was found to be an undescribed species that was previously found only in the Philippines.

Her supervisor at the Lee Kong Chian Natural History Museum, Professor Peter Ng, named the crab Nursia tohae — after her last name Toh. It was in recognition of Ms Toh’s “knack for finding small and interesting species during her many beach-combing trips”, wrote Prof Ng in the Raffles Bulletin of Zoology supplement.

Little known to many, volunteers like Ms Toh have been doing important work, on top of their day jobs, that adds to the rich biodiversity and contributes to conservation efforts in Singapore.

Their work comes in many forms, from the discovery and sightings of flora and fauna, guiding at nature reserves and parks, bird-watching to the surveying of Singapore’s shores.

Last month, NParks announced that over 500 species of marine and terrestrial animals, plants and insects have been newly discovered or rediscovered by their staff, researchers and volunteers in the past five years.

Volunteers have contributed to NParks’ work since 1993. Today, more than 25,000 have participated in a wide range of activities, such as the citizen science programmes, which allow the public to participate and collaborate in scientific research.

While the coral mimic crab she discovered was a new species, Ms Toh’s main passion is in nudibranch or sea slugs. In the Singapore Biodiversity Records, about 10 species, ranging in size from 0.2cm to 5cm, were identified and recorded by her.

Ms Toh’s love for sea slugs began when she started volunteering as a guide at Chek Jawa in 2003. Back then, she did not even know what sea slugs were. But after setting her eyes on the species’ colourful forms, she started reading up on them.

She also picked up diving so she could scour for sea slugs underwater — an activity on which she spends about 12 hours each month now.

Whenever she spots a species that looks unfamiliar, Ms Toh takes pictures of it and later verifies it against a reference book she keeps at home. If they have never been seen here before, she would contribute her sightings to the Singapore Biodiversity Records.

“There (wasn’t) a moment where I thought of giving up (on) volunteering because every time we go out, we look forward to finding stuff on our shores, and hopefully something new,” said Ms Toh, who has been guiding and searching for sea slugs for 13 years. 


But contributing to Singapore’s biodiversity is not always about discovering new species or recording first sightings in Singapore.

As bird-watcher George Cheah, 58, said when people ask if his work involves finding new species of birds: “Let’s try to keep the existing species alive first.”

Armed with a pair of binoculars, his fisherman’s hat, a clipboard and a plastic folder containing information about 30 common birds here, the vice-principal of a secondary school in the east spends two weekends in April and November — the breeding and migratory seasons respectively — as part of NParks’ Garden Bird Watch.

For about two hours in the morning during these periods, he would be at places such as East Coast Park and HortPark to identify, count and record the number of different bird species he sees.

The data collected can shed light on bird populations and where they are found around Singapore, which is useful information for better park management and conservation measures as well.

While others might think this is a small role to play, the father of two  girls finds his task meaningful in the larger picture of conservation as the authorities can keep track of the bird species and their habitat changes, for instance. If there are noticeable changes to population numbers, for example, volunteers like him would be the ones to sound the alarm bells and get the authorities to look into it, he noted.

Mr Cheah only started bird-watching last year — he decided it was time to “get back into nature” — but he can now identify some of the birds by their calls.

At the start, he had no problems spotting common birds, such as the rock pigeon and mynahs, out in the open. But things were different when it came to birds in trees. 

“It was really difficult. They were so well-camouflaged that unless they called out, sang or moved, it wasn’t easy to spot them,” he added.

Ms Ria Tan, 61, is another volunteer who chips in by keeping watch over Singapore’s shores. She has been spending about 100 days a year combing through various shores during the spring low tides, at times looking out for coral bleaching or mass fish deaths.

The founder of nature site, the former civil servant is well-known among marine enthusiasts and professionals alike. 

When Singapore experienced the longest mass coral bleaching incident last year, Ms Tan was one of the first to document it on her website. Bleaching occurs when the waters are too warm, forcing the corals to expel the algae called zooxanthellae living in their tissues and exposing their limestone skeleton.

She continues to share photos and her findings on how the corals are recovering from the bleaching episode as well as how the north-eastern coast is coping after they were affected by an oil spill in Johor. 

At times, dropping in on the shores feels like paying visits to a grandmother, she noted. “Some shores are really, literally dying. And we’ve seen grandma in better days, and every time we see her, she’s like declining a little bit more. But we still want to visit her,” she said.

To catch the low tides, she sets off sometimes as early as 2am to take a boat out to Singapore’s northern and southern shores, accompanied at times by other volunteers and researchers. She then has to transfer to a dinghy, before wading through knee-deep water to reach the reefs.

With a towel tied around her head and dressed in a neck gaiter, rash guard, track pants and dive booties, Ms Tan treads along the shore with her walking stick, stopping every now and then to take photos of the marine life, from hard and soft corals, small octopuses, sea anemone to sea cucumbers.

Unlike some others who splurge on long-distance holidays, Ms Tan spends her savings on visiting Singapore’s shores, paying S$10,000 to S$20,000 a year, mostly for hiring boats. But surveying the shores “is the most fun part of my life”, she said.

Despite her long volunteering experience, Ms Tan said she continues to struggle with raising problems or issues with the relevant stakeholders. “The thing about it is that people get angry, which is not what I want,” she said.

For instance, if someone is seen fishing illegally, she grapples with how she can raise the issue without turning the public against the individual who may not have done it with ill-intentions.

“It’s these kind of issues that cause me grief. I have to think about it, figure out a way to deal with it, which will not hurt people,” Ms Tan said.

“I think everybody is trying his best. Everyone has their own focus and constraints, it’s just a matter of finding a way to synergise, collaborate.”


Volunteering amid Singapore’s nature does not always require an individual to invest a lot of time or money.

Healthcare professional Michelle Neo, 29, who volunteers as a guide at the Singapore Botanic Gardens, said a common misconception people have is that it is a very time-consuming endeavour.

“I’m here just once a month and that is very manageable,” she said, adding that she also has the flexibility to choose when she would like to volunteer for other activities.

People also have the wrong impression that volunteer work means helping out with registration or administrative tasks, said Ms Neo, who developed an interest for plants while collecting Young Scientist badges in primary school.

“When people hear that I’m volunteering as a guide, (they) are very surprised. They wonder whether I received professional training in this area … whether I need a degree. In fact … I do not have any educational specialisation in this but it can still be done,” she added.

Nature guide Jenny Lim, 52, who has a degree in science, said she barely recalls what she learned in school because “she studied only to pass the exams”.

“I never really liked botany (that) much,” said Ms Lim, who began to develop an interest in plants only after participating in a sensory trail with her students at Pulau Ubin about seven years ago.

The senior teacher at the Movement for the Intellectually Disabled of Singapore Woodlands Garden now picks up new plant knowledge from fellow volunteers and NParks officers at their monthly sharing sessions or  on WhatsApp chat group with them.

The nature guide at Pulau Ubin and the Istana also applied what she has learnt by setting up a butterfly garden at her school last year. 

To attract butterflies, they grow plants such as the Seven Candlesticks, Snakeweeds, Lantana and Rose Myrtle.

What gets her goat when she is volunteering is meeting individuals who insist on releasing non-native species, such as terrapins, into the wild and do not understand why this could damage the environment.

“There are those who might not understand the idea of why it’s important to protect our own native species and not just bring in insects or plants (that are not preyed on in that area),” she said. 

“(Sometimes) it takes time for them to buy your idea, but we don’t stop telling them what is right … We (just) do what we can.”

Read more of the latest in




Stay in the know. Anytime. Anywhere.

Subscribe to get daily news updates, insights and must reads delivered straight to your inbox.

By clicking subscribe, I agree for my personal data to be used to send me TODAY newsletters, promotional offers and for research and analysis.