- The northernmost Eurasian otter sighting in Nepal was recorded in the Karnali River, raising hopes for the species’ range expansion. But as the animal was found dead in a fishing net, conservationists highlight challenges to the species’ conservation.
- Researchers emphasize the rarity of such sightings in high-altitude, remote areas like Humla, where otters had been considered cryptic or absent for decades.
- The discovery builds on a series of recent sightings across Nepal, including in urbanized Kathmandu Valley, suggesting a wider distribution than previously known.
- Threats to otters include overfishing, poaching, hydropower projects, sand mining and net entanglement, all of which imperil not just the Eurasian otter but also Nepal’s two other otter species.
KATHMANDU — A Eurasian otter (Lutra lutra) found in the Karnali River in western Nepal marks the species’ northernmost record in the country, offering hope for range expansion but raising concerns about its long-term conservation.
As the animal was found dead in a fishing net, overfishing could add to the growing list of challenges, such as damming of rivers for planned hydropower development, sand mining and road expansion.
“This is exciting news, as even growing up near the area where the otter was discovered, I had never seen an otter myself,” said researcher Vidyaman Thapa, lead author of a recent study documenting the finding.
“Local artisanal fishermen caught the otter in a fishing net on the banks of the Karnali River at Dulli Kuna in Nepal’s Humla [district] in April 2023, and reported it to researchers working in the area,” added Thapa, who is pursuing his Ph.D. at the University of New Orleans.
In Nepal, the animal was considered a cryptic species with no confirmed evidence of its presence for decades. But that changed in 2021, following discoveries in the Barekot, Roshiand Tubang rivers, then a flurry of sightings in different parts of the country. In 2021, it was even found in the Kathmandu Valley, home to the country’s capital city, in a heavily built-up area.
“The finding is important as we confirm the northernmost documented record of the animal in Nepal,” said Rinzin Phunjok Lama, co-author of the study. “But that the animal was found dead most likely because it got strangled in a net also raises concerns about its conservation,” he added.
As their name suggests, Eurasian otters are widely distributed across Europe and Asia. According to the IUCN, they inhabit areas from sea level up to 4,120 meters (13,500 feet), with a range extending west to the Iberian Peninsula and British Isles, south to Vietnam, north to Russia and east along the frontiers of Asia.
Despite its wide range, which is likely underexplored, the IUCN estimates the Eurasian otter’s global population to be around 57,880-361,140 individuals. According to the IUCN Red List, species densities range from 0.01 to 0.04 individuals per square kilometer (approximately 0.026 to 0.104 individuals per square mile) in newly colonized areas, and can reach 0.15 to 0.72 individuals per square kilometer (approximately 0.39 to 1.86 individuals per square mile) in established populations.
The IUCN states that the areas the otters call home are extremely sensitive to human activities that disturb the flow of the river and its bankside vegetation, which impact the population of the animal, it says. The authority adds that overfishing and poaching in parts of South and Southeast Asia is also having a negative effect on the Eurasian otter. Similarly, strangulation due to transparent and monofilament nets add to conservation challenges.
Researchers say that in the case of Nepal, three challenges are pertinent not only for the Eurasian otters but also for the country’s two other otter species: the smooth-coated otter (Lutrogale perspicillata) and the Asian small-clawed otter (Aonyx cinerea). While the Eurasian otter has been found in mountain streams, rivers and lakes, the smooth-coated otter has largely been documented in the Narayani, Koshi, Karnali and Mahakali rivers. The small-clawed otter, whose presence in the country remained a mystery for 185 years, was recently documented in western Nepal. The latter two species are listed as vulnerable on the IUCN Red List, while the Eurasian otter is considered near-threatened.
“During our fieldwork for another research project, we found that there’s extensive fishing in the river,” Thapa said. “This practice is mainly driven by growing demand for fish, especially for tourists who visit Karnali,” he added.
As the area where the otter was reported is remote, it takes hours and even days for researchers or authorities to get there. This means that otter deaths due to strangulation in nets may go unreported, Thapa said.
The discovery, however, can’t be taken as conclusive evidence that there’s a viable otter population in the area, researchers not involved in the area say. Researcher Sanjan Thapa said the discovery of one individual throws open the possibility of the existence of other individuals, too, but that needs to be confirmed. “We’ve also seen that fishing is getting more and more unsustainable in Nepal. People are even removing tiniest of the fishes, leaving nothing for other animals dependent on fish,” he added.
The other cause for concern is that Nepal’s last free-flowing river could soon host a number of mega hydropower projects, such as the 900 MW Upper Karnali project and other cascading projects that could obstruct the natural flow of the rivers. “If the planned hydropower development goes ahead, it will definitely have a long-lasting impact on the otters in the Karnali,” said researcher Mohan Bikram Shrestha. “The practice of building roads on the banks of the river as well as unsustainable extraction of sand is already adding problems to otters,” he told Mongabay.
To address these challenges, Nepal first needs to carry out detailed assessments of the otters in its river systems, Shrestha said, as there are still areas where researchers are yet to reach. He said there are already unpublished records of otter populations farther north. Along with assessments, policies and laws can be introduced, along with awareness programs to help save the animals, he added.
Banner Image: A Eurasian otter (Lutra lutra), one of the otter species found in Nepal. Image by Alexander Leisser via Wikimedia Commons (CC BY-SA 4.0).
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Citation:
Thapa, V., & Lama, R. P. (2025). Artisanal fishing bycatch confirms the northernmost distribution of Eurasian otters (Lutra lutra) in Nepal. IUCN Otter Specialist Group Bulletin, 42(2), 91–97. Retrieved from https://www.iucnosgbull.org/Volume42/Thapa_Lama_2025.html
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