Officials in Changhai county released the 2-year-old in waters off Haiyang Island, far from populated areas, on Sept. 7, Xinhua reported. The goal was to place him among wild spotted seals so he could learn to survive on his own.

He hauled himself back onto a floating pontoon at Dachangshan's Golden Beach at 9:35 p.m. on Sept. 13.

A homestay owner told Qilu Evening News the seal was panting heavily and looked much thinner than before.

His route took him first to waters off Pikou on the Dalian mainland, then past Guanglu and Guapi islands.

Tian Jiashen, head of the rare marine animal protection lab at the Liaoning Ocean and Fisheries Science Research Institute, put the straight-line distance at 140 km and the actual swim at about 200 km once detours are counted.

"Spotted seals have extremely strong navigation and positioning abilities and choose suitable habitats on their own," Tian told Xinhua.

Lost at sea as a pup

Despite a name usually given to girls, Nana is male. Born in Liaodong Bay around early 2024, he lost his way on his first migration and turned up that summer off Beihai in southern China's Guangxi region, lying on floating foam boards.

He had five visible wounds. Beihai's ocean bureau launched a rescue in October 2024, and over more than a year of care his weight rose from 35 kg to 50 kg before he was flown to Dalian on Nov. 25, 2025, for rewilding training.

Nana was released with four other seals near Sanshan Island off Dalian on April 16. Rather than migrate with the wild population, he settled around Dachangshan's beach, approaching tourists and climbing onto paddleboards and speedboats, Xinhua reported.

Tian said the long period of human care had made Nana strongly dependent on people. Spotted seals are social animals, and because Nana never found a group of his own kind after release, he was more likely to seek security around humans.

Wang Xin, a marine science lecturer at Dalian Ocean University, told Science and Technology Daily the return was likely an instinctive choice driven by food, a sense of safety and memory. The island's waters are clean and rich in fish and shrimp, and its sandy beaches suit a resting seal, he said.

Local officials have decided not to move him again. "We will respect nature and respect Nana's choice, and will not intervene blindly," Changhai county chief Zhang Shengzu told Xinhua.

The county plans to build a rest hut called "Nana's Home" in the area he frequents and will run regular patrols to limit human impact so the seal keeps hunting and living as a wild animal, said Zhang Yong, director of the county's Marine Development Bureau.

On Sept. 13, the county issued an appeal to residents and visitors warning that crowding, feeding, chasing or disturbing Nana could trigger stress responses and gradually erode his ability to hunt, leaving him dependent on humans, Cover News reported.

A "Changhai Nana" social media account now posts about the seal. A Marine Development Bureau staff member surnamed Dong told Jiupai News that a county state-owned enterprise runs the account and will share daily videos and conservation information.

Spotted seals are a Class I protected species in China and the only pinnipeds that breed in Chinese waters. Around 2,000 live in Liaodong Bay, the southernmost of the species' eight breeding grounds worldwide, where pups are born on sea ice in January and February, according to Xinhua.