Bycatch on commercial fishing boat, New England. Photo: Brian Raymond
Bycatch is when a species of fish or marine mammal is unintentionally caught while fishing for a specific 'target' species. This unwanted catch is usually thrown back into the sea dead or dying, depending upon their perceived value to the fishermen. An estimated 50 million sharks are caught unintentionally as bycatch in commercial fisheries every year. Longlines, trawls, and gillnets prove to be some of the most problematic fishing methods, producing large numbers of shark bycatch. Often, these unintentionally caught sharks will have their fins removed as the fins are too valuable for many fishermen to resist.
Sharks can represent an unusually high percentage of the bycatch compared to other species because they are often the same size as the target species or they are attracted to the easy prey that has already been caught.
Longlines can extend 80 miles and have several thousand baited hooks attached to the line. Because longlines are set in the water and often left for extended periods, by the time the lines are taken in, the sharks and other marine life are often already dead. In cases when the sharks are still alive, to avoid a potentially dangerous situation, fishermen simply cut the sharks loose with line and hook still attached.
Dragging huge nets, weighted by anchors, through the ocean or along the ocean floor is a method of fishing called trawling. This technique results in significant bycatch and habitat destruction.
Gillnets are like invisible barriers hung in the water to catch fish by trapping and holding them. The fish become ensnared in the nets and when they try to escape by backing out, their gills become caught in the net. Unfortunately sharks and other non-targeted species also become entangled and are left to die.
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