Serrated wrack seaweed (Fucus serratus) growing on coastal rocks. Serrated wrack is a brown seaweed found in the intertidal zone on rocky coasts in northern Europe. The name serrated wrack" derives from the saw-toothed shape of the edges of the fronds. Seaweed is a marine algae, sometimes found floating in the sea, sometimes found attached to coastal rocks. Photographed in September, on the shores of the Moray Firth, in the Highland region of Scotland."