National Geographic News
The demand for fresh fish in homes and restaurants around the world is soaring at a time when well-established fisheries are becoming exhausted. To meet the demand, fishing boats are venturing into farther reaches of the ocean, guided by high-tech devices that include technologies originally developed for the Cold War.
The sophisticated equipment makes it possible to scope out fish and cast nets with greater accuracy, even in areas that in the past were difficult to trawl.
As a result, many deep-water species are being fished so heavily they could soon reach the point of no return, scientists warned last week in Boston at meetings of the American Association for the Advancement of Science (AAAS).
The intensified fishing operations over the past three decades "have peeled the lid off the oceans," said Callum Roberts of the University of York in Great Britain, one of the speakers in Boston.
Devices designed or perfected for precise military operationsincluding sonar technology, satellite navigation systems, and depth sensorsare now routine equipment for many commercial fishing fleets. These devices combined with detailed maps of the ocean floor prepared by the U.S. Geological Survey give boats access to deep-sea areas where fish gather and spawn.
In many cases aerial surveillance is part of the picture. Some fishing boats in the Atlantic use spotter planes while the high-value tuna industry in the Pacific uses helicopters and other tracking equipment to seek out schools of prized fish and scoop them up in huge quantities, according to the scientists.
Citing the findings of a recent survey of North Atlantic fisheries, the scientists warned that stocks of highly favored fishsuch as cod, tuna, haddock, flounder, and swordfishcould disappear from plates within a decade if these species continue to be fished at present levels.
The survey, headed by Daniel Pauly of the University of British Columbia Fisheries Center and sponsored by the Pew Charitable Trust, found that catches of popular food fish in North Atlantic waters have decreased by half over the last 50 years, although fishing has tripled in intensity.
Although the study focused on the North Atlantic, fisheries expert Andrew Rosenberg of the University of New Hampshire said similar depletion is occurring worldwide. "Around the world the percentages [of fish declines] may differ, but there is no question that overfishing is a global problem," he said.
Call for Marine Reserves
A critical measure to restore productivity, the scientists agreed, is establishing "no-take" marine reserves so fish will have some relief from the hi-tech, round-the-clock exploitation. "When there is no place for fish to hide, we can devastate entire populations," said Jeff Hutchings of the University of Dalhousie in Canada.
Some evidence suggests that severely overexploited species may not recover even decades after depletion, he said. In Canada, for example, northern cod were fished so intensively that today the population is only a small percentage of the once-abundant stocks.
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