In this aerial photo taken on May 28, 2019, harvested kelps are towed towards a nearby port in Rongcheng City, east China's Shandong Province. (Xinhua/Lin Haizhen)

In this aerial photo taken on May 28, 2019, workers harvest kelps in Rongcheng City, east China's Shandong Province. (Xinhua/Lin Haizhen)

Workers harvest kelps in Ailun Bay of Rongcheng City, east China's Shandong Province, May 29, 2019. (Xinhua/Wang Fudong)

In this aerial photo taken on May 28, 2019, harvested kelps are towed towards a nearby port in Rongcheng City, east China's Shandong Province. (Xinhua/Lin Haizhen)

In this aerial photo taken on May 28, 2019, harvested kelps are towed towards a nearby port in Rongcheng City, east China's Shandong Province. (Xinhua/Lin Haizhen)

Harvested kelps are towed towards a nearby port in Rongcheng City, east China's Shandong Province, May 28, 2019. (Xinhua/Lin Haizhen)

In this aerial photo taken on May 28, 2019, workers harvest kelps in Rongcheng City, east China's Shandong Province. (Xinhua/Lin Haizhen)