Chorda filum, commonly known as dead man's rope and sea lace, among other names, is a species of brown algae in the genus Chorda. It is widespread in the temperate waters of the northern hemisphere, along the coasts of the northern Atlantic and Pacific Oceans. It typically has long, unbranched and hollow rope-like brown fronds about 5 millimetres (0.20 in) in diameter which can reach to lengths of 8 metres (26 ft). The holdfast is disc-shaped and it is found in sheltered marine and bodies of water at depths of 5 metres (16 ft). This photograph depicts long strands of C. filum on an underwater slope in Gullmarn, a fjord in Sweden.Photograph credit: W. Carter