Knotted Wrack is seaweed (algae) that attaches to rocks and other hard shoreline habitats or just floats around in the surf. It grows on both coasts of the North Atlantic and is common on rocky shores from Portugal to the White Sea in Europe, on the coasts of Iceland and Greenland, and from Baffin Island to Delaware. Floating plants have been collected in the eastern Atlantic off the coast of Ghana just south of the equator and in the Chesapeake Bay region. Seaweed collected along the coastline was likely carried in from the North in currents and is probably largely a result of natural dispersal. But because Knotted Wrack is widely used as a packing material for baitworms shipped from the Maritime provinces of Canada and New England, it probably also arrived through discarded bait. The seaweed is commonly dumped on the shore or water by fisherman and is the most probable mechanism for introduction to upper Chesapeake Bay. Complete Record