From June every year in my hometown, seaweed (Sargassum) grows on the seabed from 5 to 10 m and clings to rock cavities, cliffs and coral reefs. Many fishermen row in baskets to the coast and dive to cut seaweed, while people on the shore wait for the tide to recede and walk to harvest. For people, seaweed is a “Manna from heaven”, not planted, not cared for, but when the season comes, the sea produces, diligent people immediately harvest a large amount.