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Longlines and the Marine Environment


(c) Chris Johnson

Longlines, called "land mines of the sea," consist of fishing line, up to 60 miles long, baited with as many as 3,000 hooks, and remain in the water for up to 16 hours. It is estimated that globally up to 10 billion hooks are set every year. The target catch is both tuna and swordfish, though they incidentally catch all sorts of other marine creatures.

Longlining is so destructive because it is non-selective, which means that it captures anything that bites the bait or becomes entangled in the lines. This destructiveness has been magnified by an increase in longlining after the international ban on high seas drift netting and increased demand for swordfish, tuna, and shark.

It is estimated that worldwide 40,000 sea turtles get caught in longlines every year. As longlining expands throughout the world, greater numbers of sea turtles are at risk.




The deaths of sea turtles are not the only harmful impacts of longlining on the marine environment. This destructive fishing technique threatens other species of sea creatures and the larger ocean ecosystem. Below are the impacts of longlines on other marine species:

Seabirds - Longlining has been identified as a major threat a number of sea bird populations, including albatrosses, petrels, and shearwaters. The baited hooks attract seabirds, who when attempting to take the bait, get caught on the hook and drown or else ingest the hooks. The annual mortality of petrels and albatrosses has been estimated at 180,000.

Monk seals - In Hawaii, longlining has had a harmful impact on endangered monk seals that, along with other factors, eventually led to the designation of critical habitat areas for the seal with a closure of fishery activities in these areas. For example, in 1990 and 1991, 13 monk seals were found with longline related injuries.

Sharks - Another victim of the incidental capture in longline fisheries are sharks. These unintended catch, while still alive, have their fins cut off as products for the Asian market for shark fin soup which fetches between $25 and $80 a bowl. Increasing public alarm has been raised about declines in shark populations and the need for increased regulations. In 1995, the Hawaii-based longline fishing fleet caught 101,773 sharks and roughly 50,000 pounds of dried shark fins were landed in Hawaii.

The impacts of longlines are not limited to the species listed above. Since longlines are nonselective fishing gear, they capture anything that gets caught on their hooks or tangled in their lines. This has a tremendous impact on overall marine biodiversity.




Sea Turtle Restoration Project • PO Box 370 • Forest Knolls, CA 94933, USA
Phone: +1 415 663 8590 • Fax: +1 415 663 9534 • info@seaturtles.org
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