Seletar Aquaculture Co-exists with, not Harms Mangrove
Aquaculture is synonymous with mangrove destruction, but the Seletar Orang Asli not only need the mangroves for their mussel farming, they developed tech based on how mussels lived in the wetlands | Photo: harvesting mussels by Aidila Razak
Writer: Aidila Razak | Editor: SL Wong
Data visualisation & Cartographers: Irma Garnesia and Louis Lugas
Published: 21 September, 2026
This is a #BLUECARBON story, part of the Macaranga Project on Climate Disinformation and Indigenous People.
Seletar aquaculture co-exists with, not harms mangroves
Aquaculture is synonymous with mangrove destruction, but the Seletar Orang Asli not only need the mangroves for their mussel farming, they developed tech based on how mussels lived in the wetlands | Photo: harvesting mussels by Aidila Razak
Writer: Aidila Razak
Editor: SL Wong
Data visualisers & cartographers: Irma Garnesia and Louis Lugas
Published: 21 September, 2026
This is a #BLUECARBON story, part of the Macaranga Project on Climate Disinformation and Indigenous People.
FROM THE AIR, Kampung Sungai Temon and the calm waters surrounding it look like an embroidered cloth. Mere meters from the Malaysia-Singapore maritime border, the aquamarine waters make up the fabric which is strewn with lines of mussel farms.
This is a 3-generation aquaculture venture by the Seletar Orang Asli of Johor, operating since the 1980s.
Sitting on the edge of the waters, along the coastlines where some Seletar homes on stilts remain, are mangrove forests that have sustained the indigenous community long before borders existed.
For decades, aquaculture has had a record of being at odds with mangrove conservation. The world over, the practice is the largest driver of mangrove loss, with forests completely cleared to create ponds at the intertidal zones.
Between 1990 and 2023, Malaysia lost 42,490 ha of its mangrove forest, according to the Forest Research Institute of Malaysia (FRIM, 2024). Johor lost the most in the last 6 years among Peninsular states (713 ha).
Among all the threats, FRIM names aquaculture as a main overall driver. Other research shows that between 2000–2012, Malaysia lost 15% of its mangrove to aquaculture of fish and shrimp.
But in Kampung Sungai Temon, under the stewardship of the Seletar, aquaculture and mangrove conservation go hand in hand.
Learning from nature
IN NATURE, mussels grow on substrates such as a rocky surface of a cliff or – as the Seletar observed – on the submerged parts of the mangrove, says third-generation mussel farmer Jefree Salim.
Mimicking nature, Jefree’s grandfather and his contemporaries would spike mangrove stakes into the ocean bed in Pantai Lido near where they lived. Hanging old fishing nets on these stakes, they found that naturally occurring mussel spat would attach themselves to the nets and grow. Once the mussels reached maturity, the fisherfolk would dive to harvest them.
“Mussel farming isn’t like shrimp or fish farming – we don’t need to buy spawn (from elsewhere), or feed the mussels; nature does it all,” says Jefree. “But the mussels don’t grow if the water is dirty or murky. The mangroves act like a filter. They help us keep the water clear.”
Orang Laut
For up to 9 generations, Jefree’s family has lived in the village in what is now known as Johor Bahru. The Seletar are Orang Laut (‘people of the sea’), coastal people who are indigenous to the Johor Straits and whose existence, identity and traditional knowledge have revolved around tides, coastal ecosystems and fishing.
Because of their historical and ecological knowledge of the coast, the Seletar understand mangroves as an important aspect of the ecosystem, acting as nurseries for many species, and in filtering water to remove pollutants, excess nutrients, and turbidity.
This knowledge is the foundation for their mussel technology.
Jefree’s grandfather was among the first to cultivate mussels in the village’s surrounding waters almost half a century ago. Thereafter, the Seletar folk innovated mussel cultivation through trial and error, explained Jefree. Today, the longline method, or rawai as the community calls it, is among the most efficient methods of mussel cultivation in the region.
The Seletar’s hard work has also resulted in a lucrative and environmentally sustainable livelihood, making a net income of RM30,000 a year for a small farm producing more than 20 tonnes of mussels. In Jefree’s 3,000-strong village alone, 4 out of 5 households farm mussels.
And so it is the Seletar sea-farmers who have helped crown Johor as the largest producer of mussels in the country, producing over 3,000 tonnes of mussels every year.
Widely adopted in Johor
The largest mussel farm in Johor is also largely spearheaded by the Seletar, along with the Malay and Chinese fishers. It is in Kampung Pasir Gudang Baru in Masai, half an hour’s drive east of Jefree’s village.
While that Seletar community received financial assistance from Petronas in 2020 to expand their mussel farm, Jefree says Kampung Sungai Temon received no such support from anyone. “Everything we have here on our own. No one trained us, or gave us funding. Everything came from our own efforts and savings, little by little.”
Indeed, the Seletar developed their longline techniques of mussel cultivation from their deep knowledge of the environment, says Dr Vivienne Wee, an anthropologist who has studied the indigenous community for decades.
“It is their marine orientation which has brought about the mussel cultivation. They would have independently discovered ways to cultivate because they have been marine foragers for generations.
“They know the different species, where they live and how they live,” she says.
Tech a research focus
Today, that knowledge is being studied by researchers at Universiti Malaysia Terengganu under the lead of human geographer Dr Jarina Jani, who received a grant from the Fisheries Department.
“The problem with us, the so-called modern, advanced people, is we want to dominate nature,” she says.
For example, the majority of Malaysian shrimp farms cultivate Panamanian shrimps, which require care beyond what the local environment can provide. “To accommodate this foreign species, we have to give them vitamins and so on, and eventually, we degrade the natural ecosystem.
“The Seletar way of mussel farming is a gentler way of making nature work for you. It’s a humbling lesson of co-existence which we have to learn. It’s not about doing much but making something that works with nature,” she says.
Mussel cultivation has been promoted and supported by the Malaysian Fisheries Development Authority in various parts of Malaysia, but few farms use the same longline rawai methods as the Seletar. Most use stakes driven into the seabed or rafts, which cost tens of thousands of ringgit to build.
Seletar Tech Development
HOW DID the Seletar technology develop? Jefree explains in detail.
Traditionally, the Seletar fisherfolk would drape their nets from tree to tree to catch crabs and fish that came in with the tide. Sometimes, mollusks would attach to the nets too.
His grandfather’s generation started staking mangroves where tides were optimal. They fashioned old nets into ropes, tying these to the stakes. They found mussel spat would attach to the net-ropes and grow well there.
This way, when the time came to harvest the mussels, the farmer just had to lift the rope out of the water. They certainly no longer had to dive into the crocodile-infested waters, risking life and limb.
Through experience, they found that the closer the ropes were to the surface, the easier the process of harvesting.
This later led to a shift to the raft method. By the time Jefree’s father’s generation took over, mussel farmers were building raft structures using wooden beams buoyed by plastic drums – not unlike a fish kelong.
On the beams, they would tie the disused fishing nets. The rope-nets would hang down, and mussel spats would attach to them. Larger rafts can cost some RM20,000 to build and more to maintain over the years.
Rawai‘s evolution
But if the idea is simply to have a substrate for the mussels to attach and grow, why not something cheaper? This is how the rawai method was born.
Each rawai line is buoyed close to the surface using multiple plastic drums. On each horizontal line, disused fishing nets are tied at regular intervals, hanging down into the water to allow mussels to latch on and grow.
The new method halved the cost, encouraging more mussel cultivators among the community. Today, most mussel farmers in Kampung Sungai Temon use the rawai method.
Jefree decided to use the same raft method that his father used because it provided a more stable and less strenuous way to harvest mussels.
It has 39 beams, relatively small compared to other rafts in the village. Atop is a small hut with a veranda and a bedroom. Inside is a single bed and a spring cradle hanging from the ceiling. The cradle was where his two daughters napped as babies, while he worked on his mussel farm.
Harvests dropping
But things have been changing. Some 10 years ago, when his older daughter was an infant, Jefree could fill up to 780 gunny sacks with the harvest from his farm, each sack weighing up to 30 kg.
Today, that number has dwindled to just 15% of what he used to harvest. In ringgit terms, that is a net income drop from RM30,000 a year to just RM5,000 a year, he says.
“We can’t rely entirely on the sea for an income anymore. Even if we do, we have to do several jobs – catch fish in the morning, cultivate mussels on the side, catch crabs in the evening and do other odd jobs to make ends meet.”
This has to do with the loss of mangroves.
Losing Land and Sea
AS THE southern Johor coastline was developed into areas such as Puteri Harbour and Forest City, large tracts of mangrove forests were cut down. Between 2017–2023, Johor lost the most mangroves among the peninsular states (713 ha). Coastlines were also reclaimed, changing the landscape entirely.
Pantai Lido where 2 generations ago, Seletar first developed their mussel farming technology, is now the high-rise Country Gardens Danga Bay development sitting on reclaimed land.
Right behind the remaining mangroves around Kampung Sungai Temon are the luxury bungalows of Taman Laguna, the barbed-wire fenced residential community. More bungalows are being built there, with signs promising buyers a “guarded & gated enclave”.
The freehold properties cost up to RM5 million per unit and located just 15km from the Woodlands border crossing into Singapore. In fact, these mangroves and Kampung Sungai Temon itself are marked as “residential use”, according to the local plan.
In 2012, the Kampung Sungai Temon community took the government and developers to court for encroaching on their traditional lands and waters. “It was crazy. Large barges carrying sand were moving through the waters where the mussels were,” Jefree recalled. “We all took our boats out to block them.”
In 2023, the community reached a settlement. They will move to another Orang Seletar settlement in Ulu Tiram, a 90-minute drive away. In return, the community will receive some RM6,500 per household as compensation, and their new settlement will be gazetted as an Orang Asli reserve.
In limbo
But 3 years on, the reserve has yet to materialise.
“It feels like we can’t really plan our lives. Are we moving or not? Should I upgrade the gallery or not?” Jefree says, referring to the Orang Seletar Culture Centre he helped build.
The centre is in urgent need of repairs. Jefree does what he can using funds from running mangrove ecotourism tours.
Meanwhile, mounds of sand for reclamation are creeping closer. One mound is only 200 m from the village, and even closer to Jefree’s mussel farming raft. Siltation has made the waters murkier and shallower. Worse, mangroves have been cleared too, and there is nothing to filter the runoff from rivers each time it rains.
“Now the mussels may attach on the upper parts of the rope but not at the bottom (where there is silt), and we have to constantly clean the ropes to make sure mussels can attach. We’re also finding that even if they do attach and grow to maturity, .. the bottom ones are dead,” Jefree says.
This means double work – the dead mussels need to be taken off the rope and the rope cleaned to allow for fresh larvae to take hold.
Slowed growth
In addition, the mussels take longer to reach maturity. If before, farmers could harvest twice a year, now it takes up to 8 months for the mussels to reach maturity.
Meanwhile, the demand for mussels is growing by the day. Wholesalers frequently contact the community for stock, saysJefree, with mussels from Kampung Sungai Temon traveling to Singapore, Kuala Lumpur and beyond.
“We can’t keep up with the demand,” he says.
When it is time to leave Kampung Sungai Temon, Jefree says he will not bring his mussel raft to the new settlement.
The water in Ulu Tiram is even murkier, he says. He doubts the longer term harvest will be worth the cost of transporting his raft. “I’ll try to sell it, and if no one wants to buy it I guess it will be left here. It’s not worth it.”
Some, says Jefree, have suggested the community replant the mangroves in Ulu Tiram to rehabilitate the habitat and restore the water quality. He acknowledged that with sponsorship and support for replanting and monitoring, it could also be a source of income for the community.
“But mangroves don’t grow into forests overnight. It will take tens of years, and without a gazette to say this is an Orang Asli reserve, the same thing could happen. Someone could come and cut them all down to build a condominium. What will it all be for?”
Shufiyan Shukur gives an overview of the Kampung Sungai Temon residents’ relocation dilemma in this video from a year ago with sweeping views of the mussel farms, village and the relocation site.
Still, the Seletar technology will not die. The farmers have already generously shared their knowledge with other coastal communities. Recently, Jefree says they shared some spat with communities in Batu Pahat further north, who were trying to start mussel cultivation.
Through human geographer Jarina, he has also connected with Selangor’s coastal Orang Asli community, the Mah Meri. “I shared how to look at the mangroves and other substrates near the water to see if there are mussels attached. If there are, then it’s possible to cultivate them,” he says.
He hopes to guide them further into running a pilot for mussel cultivation there. It will cost RM5,000 to build one cultivation system, he says. “From there, they can grow little by little,” he says.
This is a #BLUECARBON story in the Macaranga Project on Climate Disinformation and Indigenous People, supported by International Media Support (under the Digital Democracy Initiative)
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This is a #BLUECARBON story in the Macaranga Project on Climate Disinformation and Indigenous People, supported by International Media Support (under the Digital Democracy Initiative)