Spotted seals are mainly distributed in the Northwest Pacific region and are the only species of seals that breed in China, spending nearly half the year in the country.

Like migratory birds, they appear around October every year in the Liaodong Bay area, and embark on the long journey back to the Pacific in May after breeding. Although spotted seals have almost no natural enemies in the nature reserve, some are still injured or die every year, Li said.

The actual breeding period of spotted seals, however, is from January to mid-April, with the floating ice sheets on the sea being the natural maternity ward. Seal pups fatten up on protein- and fat-rich mother's milk on the floating ice for about a month before their white fur gradually sheds and they develop the strength to swim.

Newborn spotted seals are very fragile and have a poor sense of direction. Some may be hit by floating ice sheets or stranded on land after being carried away by tidal waves, leading to their death. That's why so many pups need to be rescued between January and March every year.

Li recalled an experience in early March 2009 when they found a young spotted seal, about 15 days old, with a back injury. Experts said that it must have been hit by a floating ice sheet two or three days after birth.

"When we found it, it was already on its last breath. At the time, our rescue and revival techniques were not so advanced, so we couldn't save it despite our best efforts," Li said with pain in his eyes.

Tian, who has been part of many rescue missions with Li, has made protecting spotted seals his career."Spotted seals arrived on this land before humans. Although they cannot speak, they have their own interests and needs. When the 'rights' of spotted seals are violated, I feel I should stand up and speak for them," Tian said.

To monitor and rescue seals, Tian moved into an abandoned white building in the wetland area in the nature reserve and set up the volunteer organization's office and exhibition area there.

"I have been helping protect spotted seals for 17 years and have rescued about 100 of them," he said.