Site icon Conservation news

A tale of two otters: settling in Singapore, suffering in China

  • New research shows a massive decline in China’s otter populations, including the possible local extinction of the smooth-coated otter.
  • But otters have recolonized Singapore, even appearing near the city center due to the island-nation’s campaign to clean up its rivers.
  • If China can successfully tackle fur trading and rampant river pollution, could otters one day make a comeback there?

Few urbanites have seen an otter. Fewer still have seen a “romp” of them. Yet in Singapore, the most urbanized country in the world, commuters can watch whole families breakfast on fish just a few minutes from the city center.

After gaining independence in 1965, Singapore almost immediately began cleaning up its rivers, according to N. Sivasothi, a senior lecturer of biology at the National University of Singapore (NUS). At this point, otters had become extinct on the island.

“The results were [that] the transformation of anoxic black rivers improved to the point [that] fish are well stocked and feeding the smooth-coated otters well,” he said.

It began in 1998, when a pair of smooth-coated otters (Lutrogale perspicillata) sneaked into the Sungei Buloh Wetland Reserve on the north coast from mainland Malaysia. The mangrove-forested reserve sits just across the Johor Strait from Malaysia, and the otters most likely sought refuge there from development projects on the peninsula.

By 2014, Sivasothi had recorded the otter’s expansion across the western and southern coasts of the island. By 2015, a family was dropping pups right in the heart of the city.

A smooth-coated otter dines on raw fish in Marina Bay, located in the city centre. Photograph credit: Jeffrey Teo.

Suffering in China

The Singapore story is a sanctuary of hope in a region otherwise largely hostile to aquatic weasels. A paper published in Oryx in 2017 found a devastating drop in otter populations in another part of Asia: China.

China is historically home to three species of otter. Both the smooth-coated otter and the Asian small-clawed otter (Aonyx cinereus) have been recorded in the southern tropical regions of the country, and are classified as Vulnerable on the IUCN Red List. The Eurasian otter (Lutra lutra) — Near Threatened on the IUCN Red List — enjoys the widest distribution in China, inhabiting the country’s larger temperate zone.

The scientists write, however, that “the low number of confirmed records for 2006-2016 suggests that all three otter species are on the verge of extinction in China.” The presence of the smooth-coated otter, in particular, was “unconfirmed” after the five-year study throughout the country — meaning it might be locally extinct.

A Eurasian otter sits poised on a rock. Photograph credit: Drew Avery/Creative Commons 2.0

The study puts the blame for the otter’s decline primarily on commercial hunting. Reports from the commercial fur trade in China indicated both local extinctions and 90 percent declines in regional harvests of Eurasian otters between 1950 and 1985.

“The skin of an otter is regarded by some people as the ‘diamond’ of the fur trade,” says Grace Yoxon of the International Otter Survival Fund (IOSF). Otters, lacking blubber, have incredibly hirsute pelts. Eurasian otter fur can boast up to 50,000 hairs per square centimeter, or about 322,600 hairs per square inch, compared to mink fur’s 24,000 hairs per square centimeter and a human scalp’s 200 hairs per square centimeter.

China officially protected its native otter species in 1989. But Yoxon said she’s “not convinced that fur trapping is abating.”

The scientists expressed hope that, provided there was strict prohibition, otters could rebound quickly from low numbers in China, and even tolerate human-disturbed landscapes as they do in Singapore.

But even if hunting were stopped, otters likely face a new crisis.

Pollution of some rivers might prevent otters from recolonizing vacant habitats that are otherwise suitable, according to Bosco Chan, head of the Kadoorie Conservation China Department at Kadoorie Farm and Botanic Garden in Hong Kong, and a co-author of the 2017 study. “Some of these [rivers] are so polluted [that] the food sources otters rely on may be killed or suppressed to such low numbers [that] otters can’t survive,” he said.

Lu Guang #2475 / Tianjin’s North Canal and Ziya River, a tributary of the Hai River, where the river joins the sea. Rubbish piles high in severely polluted water. 2010.5.4; Lu Guang’s China Water Survey. University of Michigan Library Digital Collections. Accessed: January 25, 2018.
A Eurasian otter found ensnared by plastic waste during the Chinese study, in Guangdong Province. Plastic pollution is one of the many threats China’s otters have to face. Photograph Credit: Kadoorie Farm & Botanic Garden

Due to a legacy of industrial pollution, an estimated 28 percent of surface water across rivers in China are “unfit for human contact,” according to a review by non-profit watchdog China Water Risk in 2016. The worst affected river, the Hai, had 41 percent of sections surveyed classified as Grade V+, which in China means not suitable for any use — dead, essentially.

“Otters are top predators and use both land and water habitats,” Yoxon said. “They are […] very susceptible to pollution, and so if you have otters it means that both habitats [land and water] must be in a healthy condition.”

“This is not only important for otters but for all species, including our own,” she added.

Since otters indicate the state of aquatic ecosystems, conservationists often refer to them as a “flagship” species: their preservation ensures the conservation of the biodiversity upon which they survive.

Settling in Singapore

Two otters munch on fish in the downtown Marina Bay. According to a blog post by N. Sivasothi, the Kallang River that empties in Marina Bay used to be known as the ‘Dead Chicken River’, on account of its filth. Photograph credit: Jeffrey Teo.

While China proves how easily otters can be wiped out, Chan has reason to be hopeful that they can stage a dramatic comeback.

“Singapore is the best example with the smooth-coated otters living right in the city center,” he said.

Singapore is infamous for its stringent anti-litter laws — even chewing gum is banned. Perhaps less well known is that the country has been cleaning up the environment ever since the late prime minister Lee Kuan Yew’s 1967 plan to turn his country into a clean “garden city beautiful with flowers and trees, and as tidy and litterless as can be.”

Singapore now has the highest density of greenery of any city in the world, based on a 2017 report. One of the recent “garden city” initiatives has been the Public Utility Board’s Active, Beautiful, Clean Waters (ABC Waters) program, which since 2006 has undertaken 32 projects to continue to restore Singapore’s waterways.

ABC Waters recently restored the canalized Kallang River, which runs through Bishan-Ang Mo Kio Park, to a “naturalized” state. In 2014 otters were spotted there; the park is in the middle of Singapore, about 9 kilometers (5.6 miles) upstream from the heavily urbanized Marina Bay estuary.

The so-called Bishan 5 family soon gave birth to five pups, becoming the Bishan 10. Enchanted readers of the country’s leading daily, The Straits Times, voted for the furry, migrant family to represent Singapore on the country’s 51st independence anniversary in 2016.

Time-lapse of an ABC Waters project to restore the Kallang River from 2009-2012 at Bishan Ang-Mo Park in central Singapore.

With the proliferation of smartphones and social media, Singapore’s otters have become increasingly popular. In 2011, NUS’s Sivasothi founded the Facebook page OtterWatch. Followers provide regular photo updates and detailed synopses of the different smooth-coated otter families’ migrations through the country.

One of the positive aspects of this newfound fame is that problems are quickly brought to the public’s attention. In late 2017, an otter dubbed Aquarius appeared to be seriously wounded by a piece of metal wire. OtterWatch coordinators and local experts quickly intervened, and by November published a video showing a rapid rescue and happy release.

“Various dedicated lay[men] have kept us informed of movements, individuals in danger, issues of potential urban conflict and aided in rescue planning through WhatsApp and Facebook groups,” Sivasothi said.

A snap of Singaporeans pause to photograph a Bishan 10 otter-crossing near Marina Bay. Photograph credit: Jeffrey Teo

Over two-thirds of otter records for Sivasothi’s 2016 research paper, published in IUCN/SCC Otter Specialist Group Bulletin, were submitted by these “non-experts” through an online form.

“Such individuals are partners contributing to the larger issue of otter conservation in Singapore,” he added.

The otter’s amicable relationship with urbanites, who otherwise rarely see wildlife beyond their screens, may help to bring greater attention to the health of rivers should pollution resurface. These charismatic animals are raising awareness about conservation for free.

The spring of hope, or the winter of despair?

Things may be changing in China too, where the government is “spending billions” to clean up its rivers, according to Chan.

One government initiative is the installation of 200,000 “river chiefs,” officials whose names and phone numbers are posted on signs beside at-risk rivers. Through close links to the government, these chiefs respond to complaints and tackle mischievous polluters.

Another initiative uses an app called Blue Map, in which tens of thousands of users share localized pollution complaints directly to the government.

“There are cases of otters [recolonizing] cleaned-up rivers, as in the U.K.,” Chan said. “Hopefully China’s otters can do the same in future.”

The United Kingdom’s story is similar to Singapore’s. In the 1970s, otters teetered on the brink of extinction there, which the government blamed on organochlorine pesticides. Today, after banning the pesticide and legislating strict protection, Eurasian otters are found in every county in the U.K.

A population of 70 otters in Singapore is small compared to the hundreds of thousands lost across China. But Singapore’s story, and that of the U.K., show that legal protections and clean rivers can encourage their resettlement.

Paradoxically, perhaps a triumphant return will depend on the very electronic gadgets that contribute to China’s current water crisis.

An otter eats a fish in front of the Gardens by the Bay nature reserve in Singapore’s city centre. Photograph credit: Jeffrey Teo


Chan, B. P. L. & Fei, L. (2017) Past and present: the status and distribution of otters (Carnivora: lutrinae) in China, Oryx, 1-8.

Theng, Meryl & N, Sivasothi. (2016). The Smooth-Coated Otter Lutrogale perspicillata (Mammalia: Mustelidae) in Singapore: Establishment and Expansion in Natural and Semi-Urban Environments. IUCN/SCC Otter Specialist Group Bulletin. 33. 37-49.


Photographs were kindly shared by Jeffrey Teo of the OtterWatch Facebook page.