How Are Scallops Caught?

Dredging

• Previously, a large portion of scallops was caught by dredging. This technique involves using a ship to drag a set of steel frames or dredges along the seabed. These frames may have "teeth," which dig into the sediment at the bottom of the sea, allowing the dredge to skid along the sea floor. With either technique, the dredge has a steel net trailing in the water behind it. The net scoops up the scallops for collection.

Trawling

• Rather than dragging a dredge along the seabed, scallops can be caught by trawling, a process by which a steel net is pulled along behind the boat. This technique is used on smooth ocean floors. The net is dragged just above the seabed. Some species of scallop, such as the Irish sea queen scallop, only swim during certain times of the year, thus avoiding the dredging gear; trawling allows these species to be caught.

Diving

• Diving is an efficient method of harvesting scallops that are inaccessible to dredges. Both SCUBA diving and diving using air supplied from the surface are used to collect scallops. As with any diving, there are specific risks related to scallop diving, especially when divers make frequent trips to and from the surface, causing a buildup and dangerous release of nitrogen in the blood. The Seri Indians in the Sea of Cortez have pioneered sustainable techniques for harvesting scallops by diving.

Sustainability

• Dredging is a notoriously damaging process that destroys or alters seabed ecology. Some efforts have been made to control the environmental impact of dredging, including limiting the use of certain fisheries, and increasing the size of the gaps in the nets to allow younger scallops to escape. This has created some limited successes in increasing scallop numbers. Diving is generally seen as the less damaging alternative if divers are careful not to harvest immature scallops, and avoid decimating densely populated areas, which may act as breeding and spawning grounds.