Overfishing


Fishing by net in Grenada, in the West Indies, does not net as much fish as it once did.

  Searching for a few good fish
They said it couldn't be done -- the oceans were inexhaustible, and humanity could haul out an ever-increasing catch without fishing worrying about tomorrow's fishing.

Not so. The signs of shortage have been gathering for almost a century. Within the last decade, they have grown inescapable:


  bullet After years of steady growth, total global catch leveled off at about 100 million metric tons in the late 1980s.


  bullet Commercial fishing is banned or heavily restricted on some of the world's richest fishing grounds. In 1992, Canada closed the Grand Banks, idling about 35,000 fishing people. And fishing has been heavily restricted on Georges Bank, the erstwhile cod-fishing Mecca that helped name Cape Cod and lure settlers to the Northeast.


  bullet Among the ocean's 200 major fish stocks, 35 percent are in decline, and another 25 percent are being fully exploited, according to the Food and Agriculture Organization (FAO).


  bullet Fishermen continue using illegal "drift nets" -- nets more than 1.5 miles long -- that create a "wall of death" in the ocean, trapping vast amounts of unwanted fish, marine mammals and seabirds along with their intended prey (see "Boats Plunder Mediterranean" in the bibliography).


After four hours of pulling, only a skimpy catch remained in the net.
Photos on this page
© 1997, David Tenenbaum

  Full speed ahead
Still, the global fishing fleet continues to exploit desirable species and move on to others as those fish are depleted. As a result, local fishing people who depend on the sea's protein for survival are getting less to eat, and the price of choice fish has soared.

UPDATED 27 APRIL 1999
The federal government revealed a new plan to restrict catches of some large and threatened fishes, including swordfish, tuna and marlin, in the Atlantic Ocean and Gulf of Mexico. Swordfish populations have crashed in the last 10 years, and the National Marine Fisheries Service proposal would reduce swordfish catches by 27 percent. The agency would also restrict the use of long lines for catching tuna and protect certain species of sharks (some of which have declined by 85 percent over the past few decades). Conservation groups attacked the plan as too little, too late, and asked that more areas be placed off-limits to fishing, so young fish could develop in safety.

It's not just the gross tonnage of fish we eat that causes problems. Fishing also destroys a huge amount of non-target species. The so-called "by-catch" fish are caught in nets or on lines and thrown back, dead, because they are too small, illegal, or unmarketable. In 1994, the FAO estimated the total fish taken to port at 77 million metric tons; 27 million tons more was wasted or harmed.

fishing Although the fish supply varies along natural cycles, overfishing can amplify the cyclic effect. "When the climate was getting bad, and the California sardine catch was going down, the fishing pressure did not let up," says University of Wisconsin-Madison fishery expert John Magnuson," so the mortality rate was increased." Magnuson headed a 1994 National Research Council report on U.S. fisheries (see "Improving the Management..." in the bibliography).

Not just overfishing
Despite the focus on overfishing, the declines also reflect destruction of fish habitat, particularly of wetlands and rivers on which many fish depend for breeding and spawning. Many local populations of Pacific salmon have gone extinct due to farming, deforestation, destruction of coastal wetlands, and dam-building along their rivers.

Nationwide, half of wetlands are already destroyed, and in Louisiana, 35 square miles of coastal wetlands -- essential nurseries for fish and shrimp -- disappear beneath the waves each year.

Furthermore, an area of oxygen-poor water caused by overfertilized water from the Mississippi River has created a dead zone in the Gulf of Mexico as big as New Jersey. William Mitsch, professor of natural resources at Ohio State University, says, people built levees along the river "to make it behave, while the river used to have the ability to naturally flood over its banks and spread nutrients over the landscape," Mitsch said. "When water naturally spills over the banks, it can drain through a riparian [riverside] corridor and come back as cleaner ground water. At a recent meeting of the Ecological Society of America, Mitsch suggested "restoring or building wetlands and riparian buffer zones along waterways" to simulate the natural cleansing process.

The dragging of nets along the bottom has been blamed for depriving young fish of protective habitat. The case makes intuitive sense, but Andrew Solow, an ecological and environmental statistician at the Woods Hole Oceanographic Institution, says it remains to be proven, and that there's evidence that bottom trawling can actually stimulate production.

Why?
Overfishing is nothing new: The Europeans noted declines in the North Sea fishery a century ago, and shortages in the U.S. Northeast go back a good 20 years. Why haven't regulators and the fishing industry reeled in a solution?

The problems can be traced to the federal Fishery Conservation Management Act, which established regional councils to manage fish within the national territory -- within 200 miles of the coast. The Northeast council has been a classic case of foxes guarding hens. Dominated by the fishing industry, the council has been reluctant to restrict business in the short term, even as a long-term disaster loomed. "The information that the industry was without a future has been available for years," says Magnuson, "but the management group responsible for it did not take action for about 15 years."

Indeed, the problem was not a lack of science, but a lack of action, says Solow. "The scientists in the National Marine Fisheries Service have been doing their job of providing scientific advice to management, but they've been more or less ignored" until lately. Today, boats on the once-abundant Georges Bank are restricted to a limited number of days at sea, and to certain net sizes.

Another state, another story
The situation is different in Alaska, where the regional council has repeatedly closed fishing grounds to protect stocks. "In Alaska, they say, and I agree, 'We've made the hard decisions,'" says Magnuson. "They have paid attention to the scientists, and were willing to shut down fisheries." The regulators' have been conservative, Magnuson adds. "Upper-level resource managers in Alaska tell the scientists who manage individual stocks, 'If you make a decision about a fishery and we find out you've underfished it, we'll chew you out in the office. But if it's overfished, we'll fire you.'"

Kai Lee, who directs the Center for Environmental Studies at Williams College, observes that the contrast may reflect political and cultural differences between a simpler, more lightly populated Alaska, where the U.S. regulates most of the fishing, and the heavily populated Northeast, with its greater industrial and cultural diversity, where the United States and Canada both have jurisdiction over fishing grounds.

With four of five species of bottom-dwelling fish slowly recovering on Georges Bank, Solow says there's "reason to be optimistic" that production may be restored in a decade or so. Unfortunately, cod and haddock are not returning to Canada's Grand Bank, leading Solow to worry that the Canadian government might cave to political pressure and permit a premature resumption of fishing.

Yet despite the overall gloom among many fishery experts, Solow sees grounds for hope. "You sometimes hear that it's impossible to manage fish or other natural resources. It's not true -- it's a question of more or less successful management."

Enough fish stories. Heard the one about the disappearing chocolate tree?


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