The United Nations Food and Agriculture Organization began collecting fishery statistics in the 1950s. About that time, industrial-scale fishing exploded; soon, more boats chased down more fish using more efficient equipment. Since then, 29 percent of commercial fish species have suffered collapses, and many more stocks have been depleted. Entire fishing industries, such as cod in Nova Scotia, have disappeared. Many fish species, like the bluefin tuna, are on the brink of extinction. Even birds and mammals that feed on fish, including humpback whales in Canada's Bay of Fundy, are losing the competition for fish to commercial fishing fleets.
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Marine scientists agree that governments must act quickly to reverse the decline in fish stocks, but recent studies illustrate just how complex fishery problems have become. Multiple strategies are needed—and needed now—to ensure that ocean health is preserved, and to motivate the fishing industry to ply its trade in a sustainable manner.
"If [positive action] happens real fast, we can conceive of things being halfway sustained," says fisheries biologist Daniel Pauly of the University of British Columbia in Vancouver, Canada. "If this doesn't happen—and it looks unlikely—then the devastation will continue."
Over the years, management authorities have addressed the problem of overfishing in many ways, with limited success. They have put annual restrictions on total catch both at the fishery and vessel levels, ending seasons once the quotas are met. They have limited the availability of fishing licenses. They've even tried paying fishers to quit the business, through boat-buyback programs. But these efforts are undermined by government subsidies to the fishing industry, Pauly says.
In a non-subsidized world, once fish stocks become depleted, fishers would no longer be able to earn a living. They would, theoretically, migrate to other livelihoods, enabling the stocks to recuperate. Once replenished, the existing fisheries would prosper, competition would move in and this boom-and-bust cycle would repeat itself.
Subsidies short-circuit this system by paying fisheries to continue fishing depleted stocks, exacerbating the decline, impoverishing the ecosystem and contributing to the cycle of escalating subsidies. Roughly $30 billion in subsidies are paid each year—about one-third of the value of world fisheries, Pauly says.
In a review paper published in Science last June, a group of researchers led by fisheries expert John Beddington of Imperial College in London argues that subsidies undermine sustainability and should be replaced with rights-based incentives. Instead of relying on complex, top-down management, the authors suggest giving ownership rights to fishers under clearly stated rules. These include harvest strategies based on the size and health of fish stocks; catch restrictions based on the size and age of fish; gear restrictions; and well-defined fishing seasons and areas. The possibility of losing ownership rights, they argue, is enough incentive for fishers to comply with the responsible behavior.
In addition to adjusting practices, another important strategy is to adjust mindsets, says marine conservationist Boris Worm of Dalhousie University in Halifax, Canada. In the past, fisheries have sought to provide the maximum catch of fish that taste good while ignoring the larger effects this tactic has on the ocean. But now scientists believe that even individual marine species have a wide-reaching influence on the ocean ecosystem. Simply put, every species that is overfished threatens the sustainability of the sea.
This effect is especially clear along the East Coast of the United States. A study published in Science in March by Dalhousie scientist Ransom Myers shows that the impact of declining great shark populations is cascading through the marine ecosystem. Since 1972, growing demand for shark fins and meat has devastated shark populations by as much as 87 percent for sandbar sharks and 99 percent for bull, dusky and hammerhead sharks. As the sharks have declined, the populations of some of their prey, especially cownose rays, have exploded. In turn, more rays feed on more mollusks; in 2004, this biodiversity shift effectively put an end to North Carolina's 100-year-old scallop fishery and now threatens seagrass habitat along the coast.
"We're more cognizant of the fact that the ocean is not just a cheap machine that produces fish," Worm says. Instead, he says, it's a very intricate world that impacts habitat, marine mammals and birds, and that acts as an enormous filter to maintain water quality.