Most commercial harvesting of scallops is currently carried out with dredges, a fishing method that is widely reported to cause extensive harm to species and sensitive marine habitats. Scallop dredges pull metal framed nets that are around 85cm wide over the seabed. They are equipped with metal teeth on the front of the dredge which dig deep into the seabed to excavate the scallops. The scallops are then flipped into the nets. This procedure is known to have the most severe ecological effect of all UK marine fisheries because it damages seabeds and the species living on it. As the dredgers are equipped with heavy engines, they can even penetrate rocky reefs.

Scientists have discovered that the recovery of seabeds and ecosystems from scallop dredging can take up to ten years. Biogenic reefs which are reefs that are made up of hard matter created by living organisms like shells, sponges and coral beds, as well as kelp and seagrass beds are often considered the most sensitive habitats. As scallops tend to live there too, dredging activities often occur on these habitats, destroying them along the way. According to a study, published in the ICES Journal of Marine Sciences, on average, 70% of coral-like maerl is removed from an area by a single dredge tow and it takes many decades for the maerl to recover. Another study argues that rocky reefs in Scotland that see scallop dredging hold 30% less fauna than rocky reefs in areas where scallop dredging is banned.