Drift nets are used in large-scale commercial fishing operations. Miles-long in length, nets are suspended from floats at various depths and set adrift in open oceans to capture fish or squid. Drift nets are constructed of a light, plastic monofilament that resists rotting. These nets are generally of a type known as gill nets, because fish usually become entangled in them by their bony gill plates. The fishing industry has found these nets to be cost-effective, but their use has become increasingly controversial. They pose a severe threat to many forms of marine life, and they have long been the object of protests and direct action from a range of environmental groups. National and international policies concerning their use have only recently begun to change.
Drift nets are not selective; there is no way to use them to target a particular species of fish. Drift nets can catch almost everything in their path, and there are few protections for species that were never intended to be caught. Although some nets can be quite efficient in capturing only certain species, the bycatch from drift nets can include not only non-commercial fish, but sea turtles, seabirds, seals and sea lions, sharks , porpoises, dolphins , and large whales. Nets that are set adrift from fishing vessels in the open ocean and never recovered pose an even more severe hazard to the marine environment. Lost nets can drift and kill animals for long periods of time, becoming what environmentalists have called "ghost nets."
Drift nets are favored by fishing industries in many countries because of their economic advantages. The equipment itself is relatively inexpensive; it is also less labor intensive than other alternatives, and it supplies larger yields because of its ability to capture fish over such broad areas. Drift-net fisheries can vary considerably, according to the target species and the type of fishing environment. In coastal areas, short nets can be set and recovered in an hour. The nets do not drift very far in this time and the environmental damage can be limited. But in the open ocean, where the target species may be widely dispersed, nets in excess of 31 mi (50 km) in length may be set and allowed to drift for 24 hours before they are recovered and stripped. The primary targets for drift netting include squid in the northern Pacific, salmon in the northeastern Pacific, tuna in the southern Pacific and eastern Atlantic, and swordfish in the Mediterranean.
Because of their cost-effectiveness, the Food and Agricultural Organization (FAO) of the United Nations actively promoted the use of drift nets during the early 1980s. Earthwatch , Earth Island Institute, and other environmental groups instituted drift-net monitoring during this period and founded public education programs to pressure drift-net fishing nations. The Sea Shepherd Conservation Society and other direct action groups have actually intervened with drift-net fishing operations on the high seas. Organizations such as these led international awareness about the dangers of drift nets, and their efforts have affected national and international policy. In December of 1991, the United Nations reversed its earlier endorsement of drift-net fishing and adopted General Assembly Regulations 44-225, 45-197, and 46-215 that totally banned high seas drift nets. The regulations applied to all international waters and went into effect on December 31, 1992. An agreement between the United States and the South and Central American countries of Costa Rica, Ecuador, Mexico, Nicaragua, Panama and Venezuela for a moratorium on drift nets was also signed. In 1998, the European Union banned all drift nets in its jurisdiction, with the exception of the Baltic Sea. The ban took effect in 2002. The regulatory body for the Baltic Sea is the International Baltic Sea Fishery Commission, which sets more liberal restrictions on nets and catch limits than the European Union (EU).
According to the United States National Marine Fisheries Service, enforcement of the drift net ban in the north Pacific has been successful, and the U.S. salmon fishery in these waters is no longer impacted by illegal drift nets. Enforcement of this ban in other waters has so far proven difficult, however, as drift net fishing is done in open oceans, far from national jurisdictions. In reaching enforceable international agreements about drift net fishing, the primary problem has been the large investment some nations have in this technology. Japan had 457 fishing vessels using drift nets in 1990, and Taiwan and Korea approximately 140 vessels each. France, Italy, and other nations own smaller fleets.
Japan and many of these nations are primarily concerned with protecting their investment, despite worldwide protest. The United States and Canada have both expressed concern about ecological integrity and the rate of unintended catch in drift nets, particularly the bycatch of North American salmon. In the 1990s, bilateral negotiations were pursued with Korea and Taiwan to control their drift net fleets. The International North Pacific Fisheries Commission has provided a forum for United States, Japan, and Canada to examine and discuss the economic advantages and environmental costs of drift net fishing. A special committee has analyzed bycatch from drift nets used in the northern Pacific. Three avenues are currently being considered to control ecological damage: the use of subsurface nets, research into the construction of biodegradable nets, and alternative gear types for capturing the same species. The Irish Sea Fisheries Board has tested trawl nets as an alternative to drift nets, and found that they are effective in catching tuna. However, environmental groups have raised the concern that trawl nets also capture significant numbers of marine mammals, and have called for restrictions on their use after the Irish Sea Fisheries Board study found that more than 140 whales and dolphins were killed by trawlers during the two year study.
[Douglas Smith and Marie H. Bundy ]
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