The raising is done first by a diesel-powered engine connected to a winch.

The mechanical system, which is attached to a system of ropes and pulleys, takes about 70 seconds to hoist the net out of water.

Then, a worker raises the net even higher manually using a wooden winch.

Mr Gerald Sim, an assistant manager for built heritage and archaeology at the NHB who researched kelongs, tells The Straits Times that such manual winches were commonplace in the past.

However, he says, they likely fell out of favour as technology progressed, and also, operating the manual winch is quite dangerous for kelong workers, who may get seriously injured if the weight of the catch causes the winch to lapse.

Explore the 360-degree video below to see how the manual winch works.

After the net is fully raised, workers scoop their catch out of it using a smaller net attached to a roughly 6m-long pole.

In a 2024 interview, Mr Ng said that for years, the kelong had a poor catch comprising mostly “trash fish” – ones unfit for the table.

Unable to be sold commercially, the catch was used to supplement feed for cultured fishes in the floating fish farm, such as sea bass, red snappers and hybrid groupers.

Mr Sim says that to his knowledge, all of Singapore’s remaining kelongs are paired with a fish farm.

A 2015 article by the Agri-Food and Veterinary Authority of Singapore, the predecessor of the Singapore Food Agency, states that kelong operators were in the 1970s encouraged to venture into cultivating fishes in cage nets – similar to the floating farm attached to Kelong E63.

The pairing of fish farms and kelongs, says Mr Sim, could be attributed to kelong owners realising that fish farming was more productive than trapping wild catch, and also a general decrease in yield from Singapore’s waters, which drove kelong owners to open farms to supplement their income.

He also says that several factors have contributed to the closures of kelongs over the decades.

For instance, kelongs are believed to have been built in the waters off Telok Ayer as early as the 1820s, but they were cleared by the late 1900s, likely to make way for increased shipping volume in the area.

New fishing methods and technologies were later introduced over the years, including in the 1920s, when there was an influx of Japanese fishermen.

They brought refrigerated storage and motorised vessels, which gained popularity over the decades and competed with traditional fishing techniques like kelong trapping.

Mr Sim notes that even when it was a British colony, Singapore relied on seafood inputs to meet local demand, and that there were significant pressures to modernise the local fishing industry in the post-World War II years due to a population boom.

“This pushed us towards more scientifically backed methods, like fish farming, for instance, in controlled environments,” he says, adding that there were other productive fishing methods that emerged, such as trawling.

“Finally, the most important thing we can’t discount is the environmental conditions beyond our control,” Mr Sim says.

“The volume of wild catch in Singapore has been whittling due to sea conditions affected by factors such as dredging, land reclamation industry and shipping,” he continues.

“I think this reminds us that ultimately, the kelong is an economic trade, and its continuity is dictated by how much seafood it can catch from the wild.”

From being one of the main inshore fishing methods in Singapore in the 1960s, there are just three kelongs left in the country’s waters today. While Kelong E63 is still standing, it ceased operations in August 2025 and is slated for demolition.

The kelongs that remain will – barring any policy changes – be the final three. No new kelong licences have been issued since 1965, and seafood produced locally is primarily farmed rather than caught or trapped.