Post 1960s the deep-water fishing industry rapidly expanded following decreased fish stocks on the continental shelves (Koslow et al. 2000). Along with it came advances in fishing gear and vessels allowing fisherman to remain at sea for longer periods of time. Since this time commercial fishing has turned into a very serious threat to CWC ecosystems, the major culprits are bottom trawlers and dredgers; these are highly destructive fishing methods, that utilise heavy equipment and tear up the sea-floor without any discrimination (Figure 9).
There is little by-catch data available but what data there is shows terrifying results. For example, in the Aleutian Islands, Alaska which contain some of the most pristine CWCs and sponge ecosystems on the planet: US federal fishery observed data indicated 2 176 648Kg by-catch between 1990 and 2002 which is 52% of all coral and sponge by-catch. (Freiwald et al. 2004).
Fishing methods also cause damage indirectly by sediment resuspension, there are few papers present on the effects of sedimentation on CWCs but logically growth rate would be affected (Dodge et al. 1974, Dodge and Lang 1983). Primarily, waste removal and feeding would be hindered.