Full nets empty seas.

• Author: Helvarg, David
• Position: Harmful effects of supertrawlers on ocean fisheries

At sea, you can smell the odor for hours. When you're about seven miles away, a broad sheen of fish oil appears on the ocean surface. Clouds of seabirds hover above the source of the slick: factory trawlers that pull tons of fish out of the water., then process the catch.

Using sonar-directed nets with mouths wide enough to snare several 747 jumbo-jets, the factory trawlers bring in up to 300,000 pounds at a time. In the Bering Sea off Alaska and Russia, the boats fish pollock. In the waters off Asia and Latin America, they pursue yellowfin, halibut, whiting, and other commercial species. They also haul up "non-target species"--crabs, sunfish, sharks, squid, and seals--which the ships chop up and flush overboard. Some 750 million pounds of this so-called by-catch are wasted each year on the North Pacific fishing grounds alone.

Super-trawlers are the latest threat to fisheries throughout the oceans, which are already in crisis. The oceans have long maintained a fecundity unmatched on land. In the 1980s, the oceans yielded as much as 100 million metric tons for human consumption--almost a third of the animal protein we consume.

But since 1990 the world's fish catch has been falling as the number of commercial fishing boats has climbed. The United Nation's Food and Agriculture Organization reports that 70 percent of the world's commercial fish species are now fully exploited, overexploited, or depleted. Once-abundant species like cod, shark, and tuna are in sharp decline, with bluefin tuna now listed as an endangered species.

About sixty factory trawlers now fish the waters off the West Coast of the United States. One is the American Triumph, whose below-deck production line can push more than 150 fish per minute through its filleting, mincing, washing, drying, mixing, and freezing machinery, turning pollock into fillet blocks and surimi, a fish product popular in Asia. The fillet blocks are used in the United States for frozen fish-sticks, fish and chips, and fast-food sandwiches.

After the trawler's multinational crew fills its freezers with 1,000 tons of fish, the ship will offload its catch at sea onto tramp steamers headed for Asia. When it has finished its at-sea operations, it brings a huge, fishy cargo to port in the United States.

But the American Triumph is not the pride of its fleet. That honor belongs to the American Monarch, a $65-million super-trawler, based in Seattle, home port to a U.S. factory fleet that didn't exist ten...