An isolated island, a limited number of tourists and elegantly decorated guesthouses sounds like a paradise for a weekend getaway from metropolitan madness, which is exactly what Huaniao Island, in Shengsi, Zhejiang province, offers, thanks to residents' efforts to restore the ecosystem.

Located at the mouth of the Yangtze River, a few hours away from the metropolises of Shanghai and Hangzhou, Huaniao and other islands in Shengsi have been a fishermen's paradise for centuries. It's the core area of the Zhoushan fishing ground, long considered the largest of its kind in China and one of the biggest worldwide.

According to local yearbooks, the annual harvest accounted for 20 percent of China's total fishery yield at its peak.

But due to overfishing, as well as pollution from the Yangtze River and the coastal shore, yields have plunged since the 1980s.

Almost all pine trees on the island were wiped out by parasites present in furniture from the mainland, with the forest coverage rate plunging by more than 20 percent at the start of the 21st century. The government has since invested 10 million yuan ($1.5 million) annually to address the issue.

"The ecosystem is always so fragile on islands like ours," said Tang Jinji, deputy head of Shengsi county.

Locals began to realize the need to take better care of their environment.

For better regulation, small wooden fishing boats have been replaced by big steel ships. Small fish have been released into the ocean and harvesting has been banned during spawning season. Thousands of hectares of mussel farms have become a major source of income, while mussels also help to clean the water.