Spotted seals rest on the tidal-flat area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China. (Photos: Xinhua/Yang Qing)

Aerial photo shows spotted seals resting on the tidal-flat area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China.

Spotted seals rest on the tidal-flat area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China.

Spotted seals are seen in the sea area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China.

Spotted seals rest on the tidal-flat area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China.

Spotted seals rest on the tidal-flat area of Sandaogou in Panjin City, northeast China's Liaoning Province, April 20, 2021. Spotted seals are under Class One national protection in China.