Cold-water corals are Cnidarians belonging to the class Anthozoa. Their existence has been known for the past 250 years (Roberts et al. 2009). Compared to their tropical counterparts, it can be thought that there has been little research into cold-water corals in the past, however, since the 1990’s this has changed considerably and are now thought to be a very important ecosystem within the World’s oceans (Wienberg et al 2009).
According to Davies (2010) cold-water corals are split up into two main sub classes, soft corals and hard corals. Soft corals are known as Alcyonaria, including seafans and sea pens. They are commonly recognised by their several polyps and nearly all species form colonies (Freiwald et al. 2004). The latter group, hard corals are known as Zoantharia, including the Zoanthids and scleactinians. The hard corals are made up of a single polyp which is surrounded by a calcareous skeleton, when the coral dies the calcareous skeleton then breaks down and forms limestone (Freiwald et al. 2004).