Workers harvest kelp in Lidao Township, Rongcheng, east China's Shandong Province, June 4, 2020. As kelp here has entered harvest season recently, many migrant workers from other provinces returned to Rongcheng to participate in kelp harvest work. (Xinhua/Wang Yang)

A worker harvests kelp in Lidao Township, Rongcheng, east China's Shandong Province, June 4, 2020. As kelp here has entered harvest season recently, many migrant workers from other provinces returned to Rongcheng to participate in kelp harvest work. (Xinhua/Wang Yang)

A worker dries kelp in Lidao Township, Rongcheng, east China's Shandong Province, June 4, 2020. As kelp here has entered harvest season recently, many migrant workers from other provinces returned to Rongcheng to participate in kelp harvest work. (Xinhua/Wang Yang)