Furcellaria

Furcellaria is a genus of red algae which has commercial importance as a raw material for carrageenan production. It is mainly harvested from the waters of Denmark and Canada.

The most important species, Furcellaria lumbricalis, grows on submerged rocks to a depth of about 12 metres (40 ft), but it can also grow in large floating mats, which are easier to harvest.

F. lumbricalis is also an important habitat-forming seaweed, forming underwater "belts" often just below those of bladderwrack. These belts provide spawning habitat for many fish species, and for this reason some governments place regulations on the harvesting of this seaweed.