Dead Seas: Big fleets, technology, blooming demand for seafood are killing
Most of the Earth's surface is covered by oceans and their vastness and biological bounty were long thought to be immune to human influence. But no more. Scientists and marine experts say decades of industrial-scale assaults are taking a heavy toll.
More than 70 per cent of commercial fish stocks are now considered fully exploited, overfished or collapsed. Sea birds and mammals are endangered. And a growing number of marine species are reaching the precariously low levels where extinction is considered a possibility.
"It's an incipient disaster," said Richard Ellis, author of The Empty Ocean.
A rush of studies, reports, books and conferences have described the situation as a crisis and urged governments and industry to make changes.
Behind the assault, experts say, are advances in technology, subsidies to fishing fleets and booming markets for seafood. Demand is up partly because fish is considered healthier to eat than chicken and red meat.
Directed by precise sonar and navigation gear, more than 23,000 fishing vessels of more than 100 tonnes and several million small ones are scouring the sea with trawls that sweep up bottom fish and shrimp; setting kilometres of lines and hooks baited for tuna, swordfish and other big predators; and deploying other gear in a hunt for seafood in ever deeper, more distant waters.
Flash freezers allow them to preserve their catch so they can sweep waters right to the fringes of Antarctica. The trade is so global that an 80-year-old Patagonian toothfish hooked south of Australia can end up served by its more market-friendly name, Chilean sea bass, in a San Francisco bistro.
Industry officials say overfishing and disregard for environmental harm peaked a decade ago. They point to gear that avoids unintended catches, quotas and other limits, and agreements to conserve ocean-roaming fish like tuna.
U.S. fisheries officials note that although 80 U.S. fish stocks have serious problems, restoration plans are in effect, and other stocks are rebounding. The North Atlantic swordfish is often cited as a success. After limits were imposed four years ago, it has largely recovered.
Pietro Parravano, who trolls for salmon out of Half Moon Bay, Calif., south of San Francisco, said critics tended to overlook damage by pollution and destruction of coastal wetlands. "It's not just our activity that's leading to this decline," he said.
Experts worry about extinctions. Marine scientists have recently reported that improvements in fish stocks, where seen, are from depleted base lines that are a dim hint of the ocean's former bounty. In the early 20th century, harpooned swordfish were routinely 130 kilograms apiece. Swordfish caught on long-line hooks by the mid-1990s averaged less than 40 kilos, barely big enough to reproduce. Improvements since then, biologists say, hardly represent a resurgence.
Cod, which once could reach almost 2 metres in length, have essentially vanished off eastern Canada. Despite closures of fishing grounds, they may never come back, biologists say, because overfishing has so profoundly changed the ecosystem.
One consolation to biologists measuring such changes is knowing that commercial extinction - the point when a fishery is abandoned because of plummeting yields - generally comes before extinction.
Complete regional depletion appears to be possible, though. In 2000, the American Fisheries Society, representing fishery scientists and managers, reported that populations of 22 species, including skates, sturgeons and groupers, had almost vanished.
The fleets from around the world are sustaining harvests only by moving into untapped resources, said Daniel Pauly, a marine scientist at the University of British Columbia and co-author of In a Perfect Ocean, a detailed analysis showing enormous drops in North Atlantic catches over the last century.
Recent studies have estimated that stocks of many fish are now one-tenth of what they were 50 years ago. As prized species have diminished, fleets have gone further down the food chain, for smaller fish, more squid, even jellyfish and shrimplike krill.
Industry calls it "biomass extraction" and turns the harvest into fish sticks, protein concentrates for livestock or pellets to feed cage-raised salmon.
International agreements protect some species, like tuna and swordfish in the Atlantic. But most fisheries in international waters are rarely monitored.
Declining catches have led to fast growth in fish farming and other aquaculture. But this has an ecological price. Salmon and shrimp farms expanding in coastal waters from the Bay of Bengal to the Bay of Fundy displace ecosystems that are nurseries for much sea life, or they threaten local species through releas of nutrient-loaded waste, non-native species or diseases.
The result has been a terrifying transformation, said Sylvia Earle, formerly chief scientist of the National Oceanic and Atmospheric Administration. "Fleets of squid boats can be seen by astronauts," she said. The lights attract big-eyed cephalopods. "And with the demise of these creatures," she said, "the ecosystems upon which they're dependent become unravelled."
The causes: Demand for fish is booming. Experts say the industry expansion has been driven by growing populations and prosperity around the world. Almost a billion people now rely primarily on fish for protein.
The remedies: A new 'ocean ethic' is recommended. A host of scientists and organizations have recently sounded alarms and proposed solutions. Last summer, nations at an environmental summit in Johannesburg, South Africa, agreed to manage fisheries in a sustainable fashion by 2015.
In June, the Pew Oceans Commission - with a nonpartisan membership including fishermen, scientists and elected officials - recommended "a serious rethinking of ocean law, informed by a new ocean ethic."
The most important recovery strategy of all is simply to fish less, experts say. This can be accomplished in many ways.
Harvest limits can be set, with quotas allotted to people who can trade them. Iceland set the standard for this approach, which has also been adopted in a few U.S. fisheries. By limiting the overall catch and allowing people to buy and sell rights, the system encourages some to leave the business, said William Hogarth, director of the National Marine Fisheries Service.
Fishing pressure can also be cut by creating marine reserves or closing some areas to create nurseries. Some biologists have proposed that 20 percent of the oceans be set aside, although experts say monitoring against piracy will be impossible
Reserves in coastal waters have already proved their worth, with rising catches in nearby areas. A notable success has been in St. Lucia, in the Caribbean, where reserves established in the mid-1990s increased nearby catches up to 90 per cent.
Some closures in U.S. waters have led to sharp recoveries,
Hogarth said, of the fisheries service. After a shutdown of bottom fishing
in 1994 in New England, he said, "scallops came back to record levels"
and overall abundance soared.