Washington Post Staff Writer
Wednesday 14 May 2003
Industrial fishing practices have decimated every one of the world's biggest and most economically important species of fish, according to a new and detailed global analysis that challenges current fisheries protection policies.
Fully 90 percent of each of the world's large ocean species, including cod, halibut, tuna, swordfish and marlin, has disappeared from the world's oceans in recent decades, according to the Canadian analysis -- the first to use historical data dating to the beginning of large-scale fishing, in the 1950s.
The new research found that fishing has become so efficient that it typically takes just 15 years to remove 80 percent or more of any species that becomes the focus of a fleet's attention. Some populations have disappeared within just a few years, belying the oceans' reputation as a refuge and resource of nearly infinite proportions.
"You'd think the ocean is so large, these things would have someplace to hide," said Ransom Myers, who conducted the new study with fellow marine ecologist Boris Worm of Dalhousie University in Halifax, Nova Scotia. "But it doesn't matter where you look, the story is the same. We are really too good at killing these things."
If current practices continue, Myers said, the world can expect serious economic disruptions, food shortages in seafood-dependent developing nations and lasting damage to marine ecosystems. But shortsighted environmental policies and pressure from industrial fishing interests have largely stymied domestic and international efforts to rebuild failing populations, Myers and others said.
Even where recovery efforts are underway, the new work suggests that targets are much lower than they ought to be -- reflecting a global memory loss about just how many fish once roamed the sea and how large they once were.
"It's an incredibly important paper," said Jeremy Jackson, a professor at Scripps Institution of Oceanography in La Jolla, Calif., who has decried the problem of "shifting baselines," in which people keep redefining "normal" as they become accustomed to increasingly degraded environments. "The science is unassailable. And the industry knows damn well it's getting harder and harder to keep up."
The new work, published in today's issue of the journal Nature, used data collected by governments and the fishing industry going back 50 years and more. The team uncovered many long-forgotten records, including survey data compiled in advance of major fishing expeditions and initial catch data from early forays into new areas.
It took a decade just to gather all the numbers. But as they worked through the statistics, Myers and Worm saw a pattern emerging in all 13 continental shelf and oceanic systems they studied: The sea was a much more bountiful place a few decades ago than they had imagined, and fishing's impact on ocean ecosystems has been vastly underestimated.
Much of the decline can be attributed to the advent of "longline fishing," perfected by the Japanese, in which fishing lines as long as 60 miles, bearing thousands of hooks, are trailed behind a single boat. On the open ocean, the study found, those catches typically declined tenfold -- from about 10 fish per hundred hooks to just one -- in the first decade of fishing.
Sometimes the declines were even steeper. In the Gulf of Thailand, for example, 60 percent of the large finfish, sharks and skates disappeared during the first five years of industrialized trawl fishing in the 1960s. Along the narrow continental shelf near South Georgia island in the South Atlantic, where large predatory fish once were plentiful, virtually all disappeared after just two years of intensive fishing in the 1970s.
"The chronic problem we have in evaluating fisheries is we don't have good data on the size of a population until the fishing is well underway, so we didn't really have a way of evaluating how severe the problem is," said Jane Lubchenco, a professor of zoology at Oregon State University in Corvallis. "What Myers and Worm have done is a laborious, painstaking, comprehensive and careful analysis to try to rectify that situation."
Some experts warned against reading too much into the latest figures, saying it is unreasonable to expect pristine population levels when an increasing share of the world's growing population is turning to fish.
"The expected outcome of fishing is that stocks will decline," said Michael Sissenwine, director of scientific programs with the National Marine Fisheries Service, which this week released a relatively upbeat annual assessment of U.S. fish populations. "Even with very efficient sustainability plans in place you have to expect declines, sometimes of 50 percent or more. The issue is how much of a decline is reasonable and sustainable."
According to the U.S. figures released this week, American fisheries have been experiencing "steady, incremental improvement," with some species once in trouble now "fully rebuilt" and scores of other species "recovering." But the Canadian report calls into question the meaning of those terms. Is it fair, some experts asked, to call a population "rebuilt" when it has been restored to the level of a decade ago -- a level already 90 percent below what it was before the trawlers came?
"The issue of shifting baselines is critical," said Lee Crockett, executive director of the Marine Fish Conservation Network, a national coalition of more than 150 commercial and recreational fishing interests and environmental groups, which has criticized the U.S. reporting system as a politicized overstatement of ecosystem health.
Zeke Grader, executive director of the Pacific Coast Federation of Fishermen's Associations -- the West Coast's largest organization of commercial fishermen -- pointed to Alaska's recent successes in achieving sustainable fishing practices as evidence that there are "glimmers of hope." Nonetheless, he acknowledged, "we need to do much better."
The Canadian report does not focus on solutions -- two major U.S.-based fisheries commissions are expected to release recommendations soon -- but Myers said the key is to reduce, at least temporarily, catches in many areas.
"If stocks were restored to higher abundance, we could get just as much fish out of the ocean by putting in only one-third to one-tenth of the effort," he said. "It would be difficult for fishermen initially, but they will see the gains in the long run."
Others have called for the creation of a network of undersea reserves; a reduction in fishing industry subsidies; and improved technology to reduce the unintended "bycatch," which accounts for as much as 25 percent of each haul and is typically killed and tossed back to sea.