Fished Out
It's not too late to rescue the oceans--and keep seafood on our plates
An international fleet of fishing vessels works year-round to supply the new hunger in the West and to feed the growing demand in affluent areas of Asia. Fishers now scour every corner of the ocean, snapping up everything from sea urchins at the water's edge to orange roughies in the abyss, thousands of yards down. Spurred by government subsidies, guided by sonar, satellites, and aircraft, and deploying acres of nets and lines 50 miles long, this global armada has taken one recreational fishfinder's boastful motto--"The fish have nowhere to hide"--and made it the simple truth.
After decades of trying--and often failing--to manage fisheries one stock at a time, scientists are finally learning how to assess the effects of fishing on whole communities of species. The big picture is disturbing. In a report last month, fisheries scientists Ransom Myers and Boris Worm showed that the abundance of large ocean fish--bottom-dwelling groundfish like cod and open-ocean swimmers like tunas, swordfish, marlins, and sharks--has plummeted by 90 percent since industrialized fishing got going after World War II.
The researchers, who tracked scientific studies from coastal areas and catch data from Japanese long-line fishers in the open ocean, also saw a repeated pattern: Just about every time a new species becomes a quarry or boats move into a new fishing ground, populations nose-dive within 10 to 15 years. With precious few untapped resources remaining in the sea, "this is not just some fish in some areas," says Myers, who is at Dalhousie University in Halifax, Nova Scotia. "This is every large fish you look at, everywhere in the world."
The pursuit of one fish often hits other species hard. Gill nets, trawls, and long-line hooks catch nontarget fishes and other marine life, including seals, dolphins, and endangered sea turtles. This "bycatch," which is generally discarded, makes up roughly 25 percent of the total catch; some 2.3 billion pounds of sea life fall prey to oceanic collateral damage in U.S. waters every year. Baited long-line hooks also prove irresistible to seabirds; more than 100,000 are killed each year just in the Chilean sea bass fishery around Antarctica. And the trawls used to catch bottom dwellers like shrimp, cod, flounder, and pollock flatten sponges, corals, and rocky nooks and crannies where baby fish need to hide if they're to survive to adulthood. The rush to catch large fish, says Worm, "could bring about a complete reorganization of ocean ecosystems."
Many depleted species, like the North Atlantic cod, may never recover because their habitat has been destroyed or too few survivors remain to find mates. Extreme fishing pressure can also force magnificent fish to evolve into something considerably less grand. In Alaska, says Stanford University evolutionary biologist Steve Palumbi, the average size of a spawning pink salmon has dropped by 35 percent over the past two decades because only those thin enough to squirm through the mesh of a gill net survive to reproduce. "They're not getting to be the big lunkers we like to catch anymore," says Palumbi. And because the changes are genetic, perhaps they never will.
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