A recent review of marine fisheries concluded that a startling 90 percent of the world's large predatory fish, including tuna, swordfish, cod, halibut, and flounder, have disappeared in the past 50 years. This 10-year study by Ransom Myers and Boris Worm at Canada's Dalhousie University attributes the decline to a growing demand for seafood, coupled with an expanding global fleet of technologically efficient boats.

Once thought to be inexhaustible, the world's fisheries are now showing their vulnerability. The United Nations Food and Agriculture Organization (FAO) estimates that three quarters of the world's oceanic fisheries are being fished at or beyond their sustainable yields. The innovations that have allowed us to pull more fish out of the oceans—larger and more-powerful boats (some with on-deck processing facilities), improved fishing gears, and navigational and fish-finding technologies—may undermine the oceans' presumed resilience.

Data show that once large boats target a fishery, they can deplete populations in a matter of years. Within 15 years, some 80 percent of the large fish are lost. Smaller species may initially flourish, but often their populations soon crash too, either because of a limited food supply, overcrowding, and disease or because they become targets for those who are "fishing down the food web." The average size of top predatory fish is now only one fifth to one half that in the past, in part because the fish left to breed are the ones small enough to escape from nets. Another problem is that slow-maturing fish are often caught before they are old enough to reproduce.

Fishing gears are frequently indiscriminate. Trawlers drag enormous nets over a vast area, virtually clearcutting the seabed, destroying marine habitat, and taking up untargeted species. Worldwide, almost one fourth of the fish catch is discarded dead at sea, either because the fish are not marketable or because fishers have exceeded their catch allotment. Whales, dolphins, and porpoises also become part of this collateral damage. In certain fisheries, like the Gulf of Mexico shrimp fishery, the weight of this "bycatch," as it is known, may exceed that of the profitable take by 10 to 1.

After growing steadily for decades, the world fish catch has stalled between 85 million and 95 million tons since 1986. (See graph). In 2001, the world's fishing fleets landed some 92 million tons of fish, according to FAO data. An analysis by Reg Watson and Daniel Pauly at the University of British Columbia reveals that overreporting by China, the world's largest fisher, and climate—related fluctuations in Peruvian anchoveta populations may have masked an actual decline in the global catch of some 660,000 tons per year since 1988.

From 1950 to 1988, the world fish catch climbed from 19 million to 89 million tons. This fivefold expansion dwarfed the growth in global beef production during that period (from 19 million to 54 million tons). In per capita terms, the annual fish catch per person peaked at 17 kilograms in 1988, up from 8 kilograms in 1950. For most of the last half-century, we could count on a steadily growing oceanic catch to help meet the growing demand for animal protein. That era is over.

Prospects for the 1 billion people throughout the world who rely on fish as their primary source of protein and the 200 million involved with fishing and fish-related industries rest on careful management of wild fish stocks and farms. Ecologists liken fish stocks to a bank account. With a certain balance preserved in the bank, we can live off of the interest. But if we continue to dip into the principal, eventually we are left with an empty account.

The collapse of the Newfoundland cod fishery is a case in point. For centuries it was one of the world's most productive fisheries, yielding 800,000 tons of fish and employing 40,000 people at its peak in 1968. Then its stocks plummeted as a result of overharvesting and habitat damage. In 1992, the fishery was closed in an effort to save it. But it may have been too late: a decade has passed, but stocks have not recovered.

This collapse was local in scale, but the issue is much larger. Fisheries operating over the entire North Atlantic Ocean now catch half as many of the popular species—such as cod, tuna, flounder, and hake—as 50 years ago, despite tripling their efforts. Cod stocks in the North Sea and to Scotland's west are on the verge of collapse. In a 2001 report entitled Now or Never: The Cost of Canada's Cod Collapse and Disturbing Parallels With the UK, Malcolm MacGarvin urges Europe to avoid the same fate as Newfoundland's fishers.

The deterioration of oceanic fisheries can be reversed. Granting fishers an ownership stake in fish stocks is one way to help them understand that the more productive their fishery is, the more valuable their share. For example, fishers in Iceland and New Zealand have used marketable quotas, allowing them to sell catch rights, since the late 1980s. The upshot is smaller but more profitable catches and rebounding fish populations. The classic "tragedy of the commons" problem is averted.

Because of the complexity of marine ecosystems, some scientists are pushing for management of whole ecosystems rather than single species. In addition, studies have shown that well-positioned and fully protected marine reserves, known as fish parks, can help replenish an overfished area. By giving fish a refuge to breed and mature in, reserves can increase the size and total number of fish both in the reserve and in surrounding waters. For example, a network of reserves established off St. Lucia in 1995 has raised the catch by adjacent small-scale fishers by up to 90 percent. Preservation of nursery habitats like coral reefs, kelp forests, and coastal wetlands is integral to keeping fish in the sea for generations to come.

Consumers can promote healthy fishery production by eating less fish and buying seafood from well-managed, abundantly stocked fisheries. The Seafood Lover's Guide from Audubon's Living Oceans program is one valuable reference. Chilean seabass, for example, makes the list of fish to avoid because stocks are on the verge of collapse and illegal fishing abounds. The list also distinguishes between wild Alaska salmon, which comes from a healthy fishery, and farmed salmon, which is fed meal made from wild fish and thus does not relieve pressure on marine stocks. Proper labels are needed to allow consumers to make wise purchasing decisions. The Marine Stewardship Council, a new independent international accreditation organization, has thus far certified seven fisheries as being sustainably managed with minimal environmental impact.

The capacity of the world's fishing fleet is now double the sustainable yield of fisheries. Myers and Worm from Dalhousie University believe that the global fish catch may need to be cut in half to prevent additional collapses. Reducing bycatch, creating no-take fish reserves, and managing marine ecosystems for long-term sustainability instead of short-term economic gain are all policy tools that can help preserve the world's fish stocks. If these are coupled with a redirection of annual fishing industry subsidies of at least $15 billion to alternatives such as the retraining of fishers, there could be a big payoff. It is difficult to overestimate the urgency of saving the world's fish stocks. Once fisheries collapse, there is no guarantee they will recover.

Copyright © 2003 Earth Policy Institute