The Impact of Ghostnets on Marine Wildlife

Deva Murthy
10-22-1998

Ghostfishing is a term which refers to lost or abandoned fishing gear, such as nets and traps, that continues to fish unattended. Ghostnets, common gillnets in particular, are a very destructive and persistent form of marine debris. They originate during fishing operations when nets are either damaged, lost or abandoned, and left unrecovered. is a term which refers to lost or abandoned fishing gear, such as nets and traps, that continues to fish unattended. Ghostnets, common gillnets in particular, are a very destructive and persistent form of marine debris. They originate during fishing operations when nets are either damaged, lost or abandoned, and left unrecovered.

Large sections of ghostnets will eventually become tangled and form a loose ball, but are believed to fish both on the surface and at the bottom for extended periods of time. Since many gillnets today are made of monofilament, or singe strand, nylon mesh, often they are almost invisible to those animals who become entangled. Ghostnets are undoubtedly responsible for the death of large numbers of marine creatures, worldwide, each year, such as sea turtles, dolphins, porpoises, whales, sea lions, seals , manta rays, sharks, and various other species of fish and seabirds.

In 1992, the United Nations declared a moratorium on the use of gillnets more than 200 miles offshore, in the open ocean. These nets are, however, still in widespread use in fishing operations around the world.

Fisheries which use driftnets (large gillnets left to drift at sea in order to catch fish more easily) are a significant contributor to the problem of ghostnets. These are mainly fishing fleets from Japan, Taiwan and South Korea who fish squid, salmon and tuna in the North and South Pacific, Indian and Atlantic Oceans. Spanish and Italian vessels also use this method in the Mediterranean. It is quite common for these driftnets to be damaged during fishing operations, causing large sections of net to break away and continue fishing unattended. Although these ghostnets originate at sea, they often drift into coastal areas and pose a threat to other fisheries, as well as some rare or endangered species. In the early 1990’s it was estimated that in the North Pacific alone, 12 miles of net was lost each night of the fishing season, and 639 miles of net were lost each year.

Some examples of ghostnet casualties:

In 1978 a 3500 meter section of lost driftnet was found floating in the North Pacific. 1500 meters of the net was recovered and contained 75 recently caught salmon, more than 150 rotten salmon, 99 seabirds (such as albatrosses, tufted puffins, shearwaters and northern fulmars) and other assorted fish.
In 1985, a Japanese drifnet vessel recovered four sections of lost net which were 30 to 86 meters long. All sections were found to have live and dead animals entangled, including yellowtail, pomfret, two hammerhead sharks, three blue sharks, an ocean sunfish and a fur seal.
In the Sea of Cortez, in Mexico, it is commonplace for manta rays to die after becoming entangled in ghostnets.
In the 1980’s it was estimated that approximately 30 000 northern fur seals die each year after becoming entangled in marine debris, which consisted mainly of lost or abandoned fishing gear.
In the Wider Caribbean Region, tens of thousands of sea turtles die each year after becoming entangled in active or abandoned fishing gear.