n the waters off the Florida Keys, the stock sizes of all grouper species are 10 percent of what historical sizes were, and about half of snapper species exist at population levels below the federal definition of overfishing. As they disappear, smaller fish such as grunts also show signs of decline. As one researcher puts it, “We’re fishing right on down the food chain.” South Florida is not alone. Throughout the world, commercial fish stocks are facing decline, even collapse, as the global fishing industry expands largely unchecked into ever-farther reaches of the ocean. The once-abundant cod populations of the North Atlantic are struggling to recover, and anchovy stocks off the Pacific coast of Peru and Chile show alarming signs of depletion. Blue marlin, sailfish, and other oceanic species are taken in such numbers that fully matured adults are rarely found. Some species, such as the white marlin, have completely disappeared from certain waters. According to the United Nations, 70 percent of marine fisheries worldwide are fully utilized, overfished, or depleted, and 13 of the Earth’s 15 major fishing areas are now fished at or beyond capacity. “The problem is much more severe and complicated than most of us realize,” says Nelson Ehrhardt, professor of marine biology and fisheries at the University of Miami Rosenstiel School of Marine and Atmospheric Science. “When our natural resources are exploited, many species feel the impact. Overfishing causes permanent changes throughout the entire ecosystem, the dynamics of which are not understood.”
 

In the past, when local fish stocks were depleted, others were found. The oceans once seemed limitless, serving up a steady supply of seafood for the world’s dinner tables. No longer is that the case. Last November a study published in Nature revealed that some nations, particularly China, routinely inflated their annual seafood harvests in reports to United Nations officials. Subsequent analysis revealed that rather than increasing by an average of 330,000 tons per year since 1988, the annual worldwide catch had actually declined by 360,000 tons. And this is despite an ever-larger global fishing fleet and advances in harvesting techniques and technology.

Indeed, many of those advances may compound the problem. Literally, there is no place for fish to hide. But little has been done in recent years to reduce the so-called bycatch—unwanted fish caught in the nets and on the hooks. An estimated 20 percent of all fish caught worldwide is tossed back into the sea, most of them dead. For every one pound of white shrimp caught in the Gulf of Mexico, an estimated ten pounds of bycatch is discarded.

Similarly, little has been done in recent years to reduce the damage caused by trawlers, which rake their nets along ocean bottoms, disturbing or destroying marine habitats.

Other ecological consequences of overfishing are less evident than habitat destruction. When snapper, grouper, and other predator species are heavily fished from reef areas, explains Ehrhardt, smaller herbivores drastically increase in number, overwhelming the algae and other important plant life. “There are many inter-linkages,” Ehrhardt says. “It’s easy to upset nature; difficult to place it back in balance.” Reductions in anchovy stocks off the coasts of Chile and Peru, Ehrhardt says, critically impacted populations of sea lions and some species of sea birds, which feed on anchovies. And in Florida some scientists speculate that tarpon stocks may have declined in the late 1980s after fishermen began targeting mullet—a primary prey species of the tarpon.

olicy officials say such examples may become commonplace with continued globalization of the economy. More than 75 percent of the marine fisheries catch is sold on international markets. Roughly 50 percent of all seafood sold in the United States is imported.

Local fisheries now are seen as global resources creating demand within the areas least able to regulate fish harvests. After U.S. officials banned the removal of conch from Florida waters in the mid-1980s, demand for imports from the Caribbean skyrocketed. The Bahamas, Jamaica, and other nations, historically lax with their fishing regulations, are now grappling with pending collapse of their conch populations. U.S. regulations to protect stone crabs has led to similar declines of a close cousin to the stone crab found in Chilean waters.

Unlike land animals, marine organisms rarely face extinction due to overharvesting. The sea is too vast. Rather, scientists speak of “economic extinction”—the loss of a commercially viable fishery. If a fish species proves too elusive to harvest, jobs are lost and so is a crucial food source. “One of the most important reasons why we need to manage our marine fisheries is to ensure people around the world will have enough to eat,” says Jerry Ault (Ph.D. ’88), a professor of marine biology and fisheries at the Rosenstiel School. Seafood is the primary source of protein for an estimated 1 billion people worldwide. And with the burgeoning world population, coupled with greater awareness of the health benefits of seafood, the demand for fish is expected to increase 40 percent over the next decade. In the United States alone, the commercial and recreational industries support 1.3 million jobs and generate $49 billion in sales.

The impact is even greater in developing nations. Ault, who last year helped federal officials design the Tortugas Ecological Reserve, a no-fishing zone off the Florida Keys, points out that in many poor nations, fishing accounts for more jobs and contributes more to the gross national product than any other industry. “In that regard,” says Ault, “marine management becomes an issue of national security. If you solve a country’s fishing problems you’re helping to create a stable economy.”

To that end, most scientists are recommending tighter control of the world’s fisheries. In some cases, such as with North Atlantic cod, fishing for imperiled species should be banned entirely until the population can recover. In other cases, short-term closures—as little as a few weeks per year during spawning periods—might help ensure a stable population. For nearly all commercial species, there should be quotas and size limits.

istorically, only a handful of countries have been proactive. The United States, Australia, New Zealand, and Iceland have all sought consensus from a broad coalition of marine stakeholders: fishermen, the financial sector, recreational users, and environmentalists. In some cases, fishermen have been granted property rights to nearby marine resources, affording them a greater stake in conservation efforts.

“This isn’t just a scientific problem, it is a social, economic, and political one as well,” says Bob Cowen, Maytag Professor of Ichthyology and interim director of the Center for Sustainable Fisheries at the Rosenstiel School. “We know that closures [of fisheries] can help fishing stocks rebound, but it is not always realistic to propose such a solution. Too many jobs are at stake.”

And to be fair, adds Cowen, many developing nations simply lack the infrastructure to monitor fish catches, educate fishermen, and prosecute violators. In the Caribbean island-nation of St. Lucia, which created a no-fish zone in 1995, average catch sizes in waters surrounding the reserve have doubled and, in some cases, tripled.

Such success stories provide hope for the future. David Die (Ph.D. ’90), a professor of marine biology and fisheries at the Rosenstiel School, says the global crisis of overfishing requires clear examples of how resource management translates into increased catches. In the end, he says, it is a human issue, not a scientific one.

“Science can give us a sense of what can happen, and even how we might address our problems. But science alone cannot get us out of this conundrum,” says Die. “The human side of things is a lot harder to address.”