The Fate of the Ocean
Page 5 of 12
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THE TECHNOLOGIES WE USE ABOARD Oceanus are the same employed by at least some of the 4 million commercial fishing vessels plying the ocean at any given moment. Not long ago, the growth of seagoing technologies paralleled the growth in the annual global fish harvest. But 2000 marked a decisive turning point when the global wild fish catch, which grew 500 percent between 1950 and 1997, peaked at 96 million tons despite better technologies and intensified efforts by fishers. Thereafter it has fallen by more than 3 percent per capita a year, declining to 31 pounds per capita in 2003, a rate last seen 40 years ago. Even more alarming, a 2001 reassessment published in Nature suggests the annual catch has actually been falling far longer, about 400,000 tons a year since 1988, a fact concealed by China’s misreporting of its annual catch.
Paradoxically, fishing has become so efficient as to be supremely inefficient. One of the biggest culprits is long-lining, in which a single boat sets monofilament line across 60 or more miles of ocean, each bearing vertical gangion lines that dangle at different depths, baited with up to 10,000 hooks designed to catch a variety of pelagic (open ocean) species. Each year, an estimated 2 billion longline hooks are set worldwide primarily for tuna and swordfish—though long-liners inadvertently kill far more other species that take the bait, including some 40,000 sea turtles, 300,000 seabirds, and millions of sharks annually. Thrown dead or dying back into the ocean, these unwanted species (bycatch) make up at least 25 percent of the global catch, perhaps as much as 88 billion pounds of life a year.
All told, pelagic longlines are the most widely used fishing gear on earth, and are deployed in all the oceans except the circum- polar seas. But whereas they once caught 10 fish per 100 hooks set, today they are lucky to catch one, evidence the seas are running dry. Abetting their destructiveness are the trawl fisheries, which drag nets across every square inch of the bottom of the continental shelves every two years, trawling some regions many times a season. By razing vital benthic (seafloor) ecosystems, trawlers—the brutal equivalent of fishing the seafloor with bulldozers—level an area 150 times larger than the total area of forests clearcut on land each year.
Adding to longlines and trawlers is the technology of drift nets, the nearly invisible curtains of monofilament blindsiding the life of the ocean. In the North Atlantic, shark and monkfish nets up to 150 miles long are set 1,600 feet below the surface, then left untended to sail and randomly ensnare life. In the course of operations in stormy seas, many nets are lost or abandoned—though they continue to fill with prey, which attracts predators, which likewise become trapped, die, and decay, attracting more predators. Composed of nonbiodegradable synthetics, deepwater ghostnets fish with nightmarish efficiency for years.
Fishing provides a vivid illustration of the differences in our attitudes toward the land and the sea. Nowadays we refrain from indiscriminately mowing down wildlife for food; imagine slaughtering lions by the hundreds or bears by the hundredweight, along with all the antelope, deer, wolves, raccoons, and wildebeest around them, in government-funded operations, no less. Yet that’s what we do at sea, with the world’s nations subsidizing 25 to 40 percent of total global fishing revenues. The National Marine Fisheries Service estimates that $8 billion in revenue and 300,000 jobs could be created simply by better management of U.S. fish stocks, not by continuing subsidies of fishers, their boats, and their gear.
Despite its promise, aquaculture is no better, since three pounds of wild fish are caught to feed every pound of farmed salmon sent to market—creating entirely new fisheries, which deplete hitherto unscathed wild fish populations, including krill, a critical corner-stone of the marine food web and essential to the survival of Antarctic species such as penguins. Furthermore, farmed salmon become severely contaminated by pollutants in their feed chow; some European aquacultured salmon is so badly tainted that people have been advised to consume it only once every five months [for more on which seafood is safe to eat, see here.].
The truth is that the full consequences of modern fishing methods are brutal and far-reaching, and they were not really understood before the release of a seminal study published in 2003, detailing how industrialized fisheries, in a manner akin to virulent pathogens, typically reduce the community of large fish by 80 percent within the first 15 years of exploitation. Co-authors Boris Worm and Ransom Myers of Dalhousie University in Nova Scotia concluded that in the wake of decades of such onslaughts, only 10 percent of all large fish (tuna, swordfish, marlin) and groundfish (cod, halibut, skate, and flounder) are left anywhere in the ocean. Their study was based on factors modern fisheries managers ignore: historical data; in this case, the catch reports from Japanese long-liners dating from the 1950s, when the global tuna catch was less than 500,000 tons, compared with 3.7 million tons today.
