Workers pack mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Workers load a truck with mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Workers prepare to lift mussels ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

A worker prepares to lift mussels ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Aerial photo shows boats loaded with mussels sailing ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Workers pack mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Aerial photo shows boats loaded with mussels sailing ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Workers pack mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Aerial photo shows workers washing and packing mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Aerial photo shows boats loaded with mussels sailing ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

A worker packs mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

Aerial photo shows boats loaded with mussels sailing ashore at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]

A worker shows mussels at a port in Rizhao, east China's Shandong Province, March 3, 2021. With an annual yield of two hundred million kilograms, mussels produced from Rizhao accounts for over 60 percent market share in China. [Photo/Xinhua]