Foreign officials have lauded Xiamen as the epitome of marine ecological preservation and underscored the significance of collaborative international efforts to protect the oceans.

"Back in the 1980s, the situation was absolutely different. What is happening now means that the (Chinese) government has actually made great efforts to restore ecosystems of that area and continued to protect the biodiversity of that area," Raj Kumar, Asia regional membership manager at the International Union for Conservation of Nature, said following a visit to Yundang Lake in Xiamen, a coastal city in Fujian province, on Friday.

China's success in "reversing the situation" could be promoted internationally and help spur the concerted efforts that are required to address global challenges, he added.

Kumar, together with representatives from international organizations such as the United Nations Development Programme and the World Economic Forum, as well as officials from countries including Norway and Greece, embarked on a tour of Xiamen as part of activities celebrating World Oceans Day, which fell on Saturday this year.

In Xiamen, the once bustling natural harbor of Yundang Lake deteriorated due to land reclamation, embankment construction and a growing population in the 1970s and early 1980s.

Realizing the severity of the situation, the local government rolled out a comprehensive set of measures to restore the lake in 1988, including shutting down or relocating nearby industrial plants, dredging and rebuilding the banks, and channeling seawater into the lake to revitalize the water body. Nearly 40 years of governance has yielded good results.

"This is a very hard project, and it is even harder to keep it alive and sustain it. It requires the active involvement and engagement of each and every citizen," said Petros Varelidis, secretary general for the natural environment and waters at the Greek Ministry of Environment and Energy, adding that he was impressed with the way Xiamen residents have accepted, respected and supported the government's endeavors to bring nature back to the city.

Hailing from a maritime nation, Varelidis emphasized that ocean management requires the collective efforts of different stakeholders, from individual residents' actions to global cooperation.

"We need to exchange good practices and learn from each other," he said.

He cited a memorandum of understanding signed in April between the Hellenic Center for Marine Research and the Third Institute of Oceanography of China's Ministry of Natural Resources. The two sides plan to work in areas such as the conservation of underwater cultural relics, exploitation and utilization of biological resources, ecological aquaculture, and combating harmful algal blooms and climate change. They also agreed to exchange marine monitoring data to gain a more comprehensive grasp of the state of the world's oceans.

"The ocean delivers great opportunities for value creation and prosperity for our people," said Hege Araldsen, the Norwegian consul general in Guangzhou, Guangdong province. "At the same time, we know that marine life and ecosystems are under pressure."

She said the oceans are intertwined with two critical global challenges — climate change and pollution. The issue of marine plastic waste is a growing concern, while industries associated with the oceans, such as shipping, emit substantial amounts of greenhouse gases, potentially endangering marine biodiversity, ocean ecosystems and human well-being.

"We need to build an ocean economy which puts sustainability at the center," Araldsen said.

Norway's Minister of Climate and Environment, Andreas Bjelland Eriksen, visited Xiamen University on Friday for a collaborative project between China and Norway focusing on sustainable ocean management.

The goal is to develop an effective and practical policy that considers waste management and maritime industries comprehensively, with the goal of furthering green ocean development.

While underscoring the significance of ocean protection, Beate Trankmann, the UNDP's resident representative in China, said a blue economy is also important globally.

"The preservation of our oceans should not be seen as coming at a cost of economic growth," Trankmann said.

She added that ocean resources now account for 7 percent of global GDP, and it is crucial for all nations to collaborate and promote sustainable development.

"Nature does not have geographic boundaries," she said. "Strengthening cooperation among different sectors and regions to coordinate multinational efforts across both land and sea is vital to maximize income."

Zhong Wanyu contributed to this story.