Apparently no one really remembers how many big fish used to inhabit the sea or how big they got. “The few blue marlin left today,” says Myers, “reach one-fifth of the weight they once had. In many cases, the fish caught today are under such intense fishing pressure, they never even have the chance to reproduce.” The pressure stems from a combination of economics (a single large bluefin tuna can command $100,000 on the Tokyo fish market) and ever-evolving technologies, and this scenario plagues the oceans: The more rare and endangered a species, the more money it generates and the more people who are willing to pursue it. While rich fishers pursue dwindling species with the aid of technology, poor fishers do it through brutal ingenuity, including using poison and explosives, leading to what’s known as Malthusian overfishing—when a fishery is overwhelmed yet fishing continues anyway, in ever more destructive and desperate ways, until the complete decimation of species and their ecosystems. Poor fishers do this largely to meet the demand of rich nations—to supply aquarium fish for the United States and live food fish for Hong Kong. Since demand grows in direct relationship to a species’ decline, many fish are targeted during their spawning aggregations, thus wiping out entire adult populations along with all their potential progeny. In this way, some coral reef species have been locally extinguished in the course of only one or two spawning events.
The past has much to teach us about what we’ve forgotten. By analyzing 10,000 historical restaurant menus from Boston to San Francisco, a project called the History of Marine Animal Populations, out of the University of Southern Denmark, finds that lobster was so abundant in the 19th century that middle-class Americans snubbed it as food for the poor. Likewise, the day may be near when Hemingway’s The Old Man and the Sea is seen less as a story of Santiago’s plight than of a mighty fish that once roamed the seas and no longer does.
IT USED TO BE, in the heyday of wildlife filmmaking, that you could chum off the California coast for a few hours or a day or two and attract dozens of full-size (eight-foot) blue sharks, along with a gaggle of youngsters and the occasional, powerful (10-foot) mako or two. But the last time I tried this, only two baby blue sharks, all of four feet long, appeared after days of chumming. In the interval between 1980, when cameramen were forced to work with safety divers to fend off more sharks than they knew what to do with, and 1991, when we were obliged to film the baby sharks close-up with wide-angle lenses to make them look bigger, long-liners, trawlers, and drift netters came to the west coast.
Sharks are killed incidentally in large numbers by all three forms of industrial fishing, but they are also targeted by their own fishery, primarily for soup. Once a rarefied foodstuff of the elite, today sharkfin soup is an affordable luxury for the Chinese nouveau riche who wish to prove their wealth by ordering a $100 bowl of glutinous cartilage flavored with chicken broth. At expensive eateries across Asia, middle-class diners slurp this pricey food, even as the World Conservation Union adds ever more shark species to its Red List of Threatened Species.
Fishing fleets kill an estimated 100 million sharks per year across the globe. In the Gulf of Mexico, the number of oceanic whitetip sharks has plunged 99 percent since the 1950s, driving this once common pelagic species into virtual extinction. A study of the North Atlantic found that overall shark populations have declined more than 50 percent since 1986. Sadly, sharks are slow breeders, with most delivering small litters (some only twins) after reaching a late sexual maturity (some at 25 years old), after which they typically deliver litters at three-year intervals. The results of such slow reproduction make recovery from overfishing notoriously difficult. When porbeagle sharks were overfished by Europeans in the 1960s, the species struggled for the next 30 years, finally achieving some semblance of health in the 1990s, only to become the target of U.S. and Canadian fleets that fished it into commercial extinction in three short years.
The end of big fish in the sea is more than an aesthetic loss. Marine ecologist Mark Hixon of Oregon State University has published widely on coral reef ecosystems, and his work illustrates how biodiversity and community stability thrive in the presence of predators and competitors. The removal of either or both destabilizes the remaining species. Hence big sharks, tuna, swordfish, and halibut are more than picturesque giants; they are keystone species that play greater roles in maintaining ecosystem function than seems obvious based on the size of their population.
Hixon also argues that not all spawners are created equal, and that the most valuable members of fish populations are what he and his colleagues call the Big Old Fat Female Fish (BOFFFs), who produce better-quality and -quantity eggs than younger females. Yet fisheries managers continue to promote the targeting of older fish, followed by younger fish, until none can grow old. “This means that BOFFFs are disappearing,” says Hixon. “Here on the West Coast, 7 out of 17 well-assessed species of rockfish have been declared overfished since 1999, and we believe that at least part of the explanation for these stock collapses is the result of our failure to appreciate the value of Big Old Fat Female Fish.”
Hixon tells me that we need a Kuhnian paradigm shift in fisheries management. “Current managers learned single-species management, and they’re resistant to changing that, even though it seldom works.” A scientific consensus signed by him and 218 other scientists and policy experts pleads for an updated approach: “From a scientific perspective, we now know enough to improve dramatically the conservation and management of marine systems through the implementation of ecosystem-based approaches.”
As on land, protecting places is the best way to preserve life. In 2003, the World Conservation Union listed 102,102 protected areas on earth. But only 4,116 of these were protected marine areas, preserving less than 0.5 percent of the world ocean, whereas 11.5 percent of the land surface has been granted some form of sanctuary. To reach parity, we need to add 23 times as many marine reserves and offshore national parks, or 10 times more total area—and perhaps even more, since the liquid medium of the ocean is more in-terconnected, and the fate of its disparate realms more intertwined than here.
RACHEL CARSON wrote of the sea that “in its mysterious past it encompasses all the dim origins of life and receives in the end, after, it may be, many transmutations, the dead husks of that same life. For all at last return to the sea—to Oceanus, the ocean river.” We return to the sea, too, in various husks, including in the form of atmospheric emissions. Sweden, for example, calculates that its populace of 8.9 million carries 2.8 tons of mercury fillings in their mouths, most of which is destined eventually to go airborne in crematoriums.
Crematory emissions are a small but growing percentage of the total global mercury pollution, the vast majority of which enters the foodweb as a biologically active derivative of the inorganic mercury released by the smokestacks of the coal and chlorine industries. Oxidized in the atmosphere and piggybacking on raindrops, this form of mercury eventually settles to the bottom of oceans and lakes, where it is converted to dangerous methylmercury by aquatic bacteria, which are eaten by plankton, which are eaten by fish, and bigger fish—with each subsequent meal bioaccumulating in higher levels until apex predators such as tuna and whales carry mercury levels as much as 1 million times higher than the waters around them.
As do we. Epidemiological studies show that mercury levels among Arctic peoples are high enough to cause neurobehavioral effects, while a Hong Kong study revealed that 10 percent of the region’s high school students suffer mercury poisoning from eating tuna and swordfish. The European Union warns pregnant women to limit their consumption of both tuna and swordfish because of brain damage to their unborn children, and the U.S. Food and Drug Administration warns pregnant women, lactating women, and young children not to eat swordfish, shark, tilefish, or king mackerel, though the powerful tuna lobby succeeded in keeping tuna off that list. The EPA now estimates at least one in eight American women of childbearing age has unsafe levels of mercury in her blood, and as many as 600,000 of the 4 million babies born in the United States in 2000 were exposed to unacceptable levels because their mothers ate a diet rich in fish (in a continuation of bioaccumulation, the level of mercury in a fetus’ blood can be 70 percent higher than its mother’s). Yet the Bush administration, circumventing the Clean Air Act, has enabled coal-fired power plants to delay curtailing significant mercury emissions until 2018.
IT’S MIDNIGHT OVER THE GULF OF MEXICO, the skies stripped of clouds and glittering with stars as 25-knot winds blow down from the north. For most of the residents of the bayou country of southern Louisiana, these are welcome winds; only a month has passed since Hurricane Katrina made landfall, and 11 days since Hurricane Rita, and these northerlies are cold and dry enough to dismantle any additional tropical storms from the top down. It’s also blowing sufficiently hard that Captain Craig LeBoeuf decides to sail R/V Pelican through the Intracoastal Waterway and out into the Gulf at Morgan City, so that dawn will light our way along the shallow shelf where more than 100 hurricane-broken oil rigs and drilling structures foul the waters.
This once was one of the most prolific bodies of water on earth, a place where the outflow from the Mississippi River introduced freshwater nutrients into a deepwater environment. But long before Katrina, the Gulf had become one of the world’s most polluted marine ecosystems, with mercury loads among the highest ever recorded, including levels in blue marlin 30 times above what the EPA deems safe for human consumption. An average of 10 tons of mercury comes down the Mississippi every year, with close to another ton added by the offshore drilling industry. Equally alarming, a sizable portion of the Gulf is so biologically dysfunctional on a seasonal basis that it’s known as a dead zone—the largest such area in the United States and the second largest on the planet, measuring nearly 8,000 square miles in 2001, an area larger than New Jersey.