SEOUL: Eurasian otters are making a comeback in Seoul’s Han River, decades after the endangered species disappeared from the capital’s stretch of the waterway.
A new DNA survey identified 27 otters along the river and its tributaries, up from 15 in a city-commissioned survey four years ago, a state-run institute said on Sept 3.
The National Institute of Biological Resources identified the animals by analysing DNA from 106 faecal samples collected at 27 locations between January and April.
Twenty-one otters were found along the river’s main channel and six in its tributaries.
Most were concentrated in eastern Seoul.
Five were identified around Seongnae Stream in Songpa-gu, while three each were found near Jamsil Bridge, Yangjae Stream in Gangnam-gu and Jungnang Stream in north-eastern Seoul.
Four were also identified near Hangang Bridge.
The population comprised 16 females and 11 males. Genetic analysis showed that all 27 were related, including five parent-offspring family groups.
Eurasian otters are designated as a natural monument and a Class I endangered wildlife species in South Korea.
Once common along the Han River, they declined sharply due to hunting, water pollution and the loss of natural habitat.
Concrete riverbank development and the construction of Paldang Dam also disrupted the river’s aquatic ecosystem.
An otter carcass found near Olympic Bridge in 1986 was the last recorded trace of the species in the Seoul section of the river for three decades.
In March 2016, an otter was filmed swimming in Tancheon Stream, one of the Han River’s tributaries.
A family of four was later recorded near Gwangjin Bridge in January 2017.
A 2022 survey commissioned by the Seoul government and conducted by the Association of Korean Otter Conservation identified 15 otters along the river and its tributaries.
Researchers attributed their return to improved water quality, recovering fish populations and efforts to restore natural riverbanks.
Seoul began replacing concrete embankments with soil, gravel and vegetation about 20 years ago and aims to complete all targeted sections by 2028. - The Korea Herald/ANN
