XINING－Eurasian otters have been frequently spotted in Northwest China's headwaters region and even in the more populated Yushu, Qinghai province, indicating a steady increase in the population of the endangered species, according to a recent field survey.

The China Otter Investigation and Protection Report 2019, jointly prepared by 15 Chinese conservation agencies, said the rare otter species has become increasingly active in Sanjiangyuan, dubbed "Asia's water tower," which is home to the headwaters of the Yangtze, Yellow and Lancang rivers.

The report is based on a survey conducted by the China Green Foundation, the Qinghai Provincial Ecology and Environment Department and the Sanjiangyuan National Park Administration.

During the survey, carried out from December 2017 to December this year, researchers walked about 400 kilometers, studying otter traces such as feces. In places that are havens for otter activities, researchers deployed 21 infrared cameras.

Zhao Xiang of the Beijing Landscape Nature Conservation Center, who took part in the report, said that Eurasian otters are regarded as indicator species of river ecosystems, as their presence indicates high water quality.

He said the otter research shows the local ecology is enjoying steady and comprehensive improvement.

The report also mentions the presence of the small-claw river otter, which has faced extinction over the past 30 years due to pollution and illegal hunting, as it has been pursued for its fur. The species is banned for trading, according to the Convention on International Trade in Endangered Species of Wild Fauna and Flora.

The report underscores that the investigated area is less than 4 percent of the animals' distribution area, and 80 percent of otter habitats are not under national park protection.

The Qinghai government has intensified otter protection by prohibiting poaching and releasing fish species alien to the local environment. It has adopted the strictest ecological policies among China's provincial-level administrations, as the plateau ecology critical for the rivers' well-being is fragile.

The government has built a remote monitoring system for real-time, round-the-clock data transmission to reinforce the protection of otters in key river sections.