A Pew Marine Conservation Fellow Documents Humankind's Tragic Handling of the World's Oceans. He also Has a Remedy
Today's oceans are less diverse, bountiful, productive and beautiful than those of a century ago. The differences are chronicled in Callum Roberts's The Unnatural History of the Sea, published in July by Island Press. Yet, despite massive evidence of human devastation of a world resource, this Pew fellow remains optimistic about the potential for the seas to recover.
These excerpts are from The Unnatural History of the Sea by Callum Roberts. Copyright © 2007 by the author. Reproduced by permission of Island Press, Washington, D.C.
The Tide Turns, Favoring High-Seas Fishing - Tuna as an Example
In the early 20th century, interest grew in fishing for high-seas fish where large animals like tuna and swordfish dipped into coastal waters. The largest species were initially targets mainly for recreational fishers, the meat being considered inferior to other species readily available.
One of the world's most valuable fish today is the Atlantic bluefin tuna. In the western Atlantic, spring sees these fish migrate north from winter spawning grounds in the Gulf of Mexico to their summer feeding grounds off the Gulf of Maine and Nova Scotia. They ride the warm Gulf Stream to where this current collides with the southwardflowing cold, nutrient-rich waters of the Labrador Current. Where southern and northern seas coalesce, their vernal union begets copious plankton growth, greening the waters and filling them with fish.
Tuna epitomize what it is to be a fish. Their sleek muscle-bound bodies cut through water with effortless mastery, driven by high crescent tails beating side to side in rapid staccato. Pectoral fins shaped like hydroplanes flick and twist on the unseen marine breeze, lending remarkable agility to such stiff-bodied creatures.
Bluefin tuna are the giants of the tuna tribe. I once spent a week at White Point Lodge on the south shore of Nova Scotia. Surveying the lounge from above a roaring log fire was a magnificent moosehead whose antlers seemed to span the room. According to an inscription, when this giant commanded the woods of Nova Scotia, it weighed in at over 1,000 pounds.
Below the head were faded photographs of big-game fishers of the 1930s and 1940s. Giant bluefin suspended from dockside gantries dwarfed exhausted, grinning anglers. These fish weighed up to 1,500 pounds and reached 13 to 14 feet, humbling the mighty moose.
Prime bluefin tuna fetch over $100,000 per fish at auction and realize double the price in restaurants. Almost all bluefin today are flash frozen and flown to Japan for immediate sale at Tsukiji, the great Tokyo fish market. In the dark of early dawn, buyers pick their way among bodies that lie in stiff rows, inspecting each fish for color and fat content. Fat fish are the most valuable, and buyers judge the best by rubbing a piece of meat between finger and thumb. Only a day before, these fish may have felt the rush of the cool Atlantic on their flanks as they rode the billows of the Gulf Stream, springing shoals of herring from the water with lethal dashes.
In the 1920s and 1930s, when the anglers of White Point Resort were charming bluefin tuna from Nova Scotia seas, the fish could be sold only for pet food. However, development of canning technology and the discovery that tinned tuna preserves wonderfully well created a product for which there was a ready market.
Tuna fisheries developed first off the west coast of North America, targeting the large, white-fleshed albacore. Soon after, commercial fishers began to try their gear on east coast bluefin. One famous big-game angler of the day, Kip Farrington, lamented in 1942:
Easterners also like to harpoon giant tuna, even though they are harder to strike than swordfish. I hold no brief for this so-called sport; and, as these grand fish bring but three or four cents a pound, there is even less reason for harpooning them than there is in sticking swordfish.
The distinctions between the sport fish and commercial fish of Farrington's world were at that time being turned upside down. The giant fish, top predators of the sea, were now prey for a growing cadre of commercial fishers. By the early 1940s, Americans had developed a taste for big fish. New Englanders then landed about 3 million pounds of swordfish a year, but a further 4 million pounds were imported from Canada and Japan.
Up to the Second World War, it was still too expensive to pursue these species far offshore. Like bluefin tuna, swordfish are seasonal visitors to New England waters, arriving to work the glittering seam of fish that separates Gulf Stream from Labrador Current. They could be caught close to shore, within sight of Long Island, Cape Cod and Nova Scotia. But the entire face of high-seas fishing changed after the end of hostilities.
Both Japan and the Soviet Union were desperate for food and possessed large fleets of ships in need of peacetime occupation. For Japan, fishing was already a way of life. In the 1930s, Japan became the world's largest fishing nation, with twice the landings of the United States, for example. The Japanese fished for crab in the Bering Sea, for whales in Antarctica and for croakers and bream in the South China and Yellow seas. Japan's sizeable distant-water fishing fleet had been pressed into war service and now was released to begin fishing anew.
For the first few years postwar, Japanese fisheries concentrated on waters close to the islands, stocks benefiting from the respite in fishing caused by the war, just as did fish stocks in Europe. Fishing technology advanced rapidly, including onboard freezers that gave fishing boats greater reach, and larger nets that enabled them to fish more economically. The era of high-seas fishing had begun.
Let None Dare Call it "Fishing"
Target species like tuna are not the only animals affected by high-seas fishing operations. Although drift nets, some reaching 56 miles long and dubbed “walls of death” for their indiscriminate massacre, were banned by the United Nations in 1992, the giant longlines that have largely replaced them also exact colossal mortality on non-target species: Loggerhead, leatherback and olive ridley turtles are being slaughtered in the thousands, as were albatross of all varieties until new methods for setting lines were adopted to keep the bait away from hungry birds.
For the leatherback turtle in the Pacific, extinction may be a few breaths away. The leatherback is the largest living reptile, reaching over 1,540 pounds and over 8 feet in length. These harmless jellyfish feeders do not take hooks, but instead blunder into longlines where they get tangled and drown. Numbers of leatherbacks returning to Pacific beaches to nest— the best means we have of estimating their populations—fell from over 90,000 to less than 5,000 between 1980 and the present. Some rookeries have been lost altogether.
Boris Worm, the late Ransom Myers and colleagues used longline catch data to look at the effects of fishing on the open sea in another way. They calculated the number of different types of fish from the tuna and swordfish families caught per 50 hooks and mapped patterns across the global oceans. The study revealed rich and predictable congregations of life where ocean predators gather, with a dearth of species in others.
Areas of exceptional diversity represent oceanic crossroads and productivity hotspots such as places where warm- and cold-water currents meet. They include the mid-Atlantic east of Florida where the Gulf Stream leaves the Caribbean on its journey north; northeastern Australia in the Coral Sea; the central eastern Pacific; and the seas bordering Japan's Kuroshio Current.
These congregations have also drawn the attention of the world's fishing industry, to the detriment of the animals that live in them. Worryingly, depending on the area considered, there were declines of between 10 and 50 percent in species diversity between the 1950s and the 1990s.
Fishing is impoverishing the global oceans. After the study was published in 2005, Worm described his feelings on making this discovery:
Finding these oceanic oases was like solving a giant puzzle and seeing the night sky in constellations for the first time—even as the stars are blinking out. It's beautiful and tragic at the same time. . . . Everywhere you go, in every ocean basin, our “hotspots” today are only relics of what was once there.
Fishing is transforming the high seas. Giant predatory fish are today following the fate of the great whales, disappearing place by place, species by species. Bycatch is killing other titans of the waves: the leatherback turtle, dolphins, porpoises, whale sharks, albatross . . . the list is long.
The leatherback has a 100-millionyear evolutionary history. Today we are on the point of ending it all for the leatherback because of our unbridled desire for tuna, swordfish and marlin.
Some effects of fishing are unexpected. Tuna hunt by driving schools of their prey fish toward the surface where there is no escape. Seabirds home in on these fish boils to take advantage of easy prey pressed into the shallows from below. With the decline of tuna, prey-fish boils have become sparse, and birds find it harder to catch prey. Some species now subsist on offal discarded from fishing boats while others go hungry.
Yet other species have benefited from gaps opening in food webs as competitors are removed, but overall the trends, like those in coastal seas, are of loss. We can only guess where this will end if high-seas fisheries continue unfettered.
When nations of the world declared 200-nautical-mile Exclusive Economic Zones through the 1970s and 1980s, a third of the ocean was brought under national control for the first time. In these waters, the cherished principle of freedom of the seas was restrained as countries sought to limit access to their fisheries and other resources like oil and gas.
In waters beyond, freedom of the seas prevails almost unchanged since the 17th century. High-seas waters are governed today by international fishing agreements operated under the United Nations Law of the Sea by regional fishery management organizations. These bodies supposedly control catches from the high seas and are responsible for conserving fish stocks. Most, like the International Commission for the Conservation of Atlantic Tuna, are ineffective.
And, just as in the 16th and 17th centuries, there are still pirates at large on the high seas. Pirate fishing vessels—working beyond law and regulation—are estimated to account for up to half of the global catch from the high seas, drawn by the large profits that can still be made. They sail under flags of convenience bought from nations that have not signed up to conventions whose aim is to protect the high seas.
They land their catches in clandestine operations at least as lucrative as international drug smuggling, often with the tacit blessing of national authorities who care little for what goes on beyond their national limits. Until they are brought under control, there is little hope for rational fishery management on the high seas.
If Kip Farrington were alive today, how he would rue the loss of his beloved game fish. The waters of New England and eastern Canada no longer throng with giant bluefin and swordfish.
It is hard to know just exactly how scarce bluefin are today compared with the interwar heyday of game fishing. Since records began to be kept in the 1970s by the misnamed International Commission for the Conservation of Atlantic Tuna, bluefin have declined by over 90 percent.
But this was not the beginning of their decline. The fishery commenced over 40 years earlier. Using Ransom Myers and Boris Worm's estimate of 80 percent decline in stocks in the first 15 years of the fishery as a conservative lower bound for pre-1970 decline, there is probably only one bluefin left for every 50 present in 1940.
The last of these regal fish are today pursued more relentlessly than ever by the descendents of the harpooners that Farrington railed against. The fish are now so valuable that it pays to employ planes and helicopters to scan the ocean, guiding boats in for the kill when fish are spotted. This isn't fishing any more—it is the extermination of a species.
Picking the Table Clean
Somewhere off the West African coast, in a sea that is empty from horizon to horizon, a floating log bobs up and down with the passing waves. From above, it is the only object in an endless spread of water, adrift and isolated. From beneath, it is landmark and focus in the lives of countless fish and other animals.
Shoals of tiny baitfish hang beneath the log, darting back and forth in nervous shimmering masses as it shifts with the waves. Jellyfish pulse in the gentle current, trailing curtains of tentacles among which juvenile fish shelter, looking like silver baubles. A school of skipjack tuna circles languidly in the water around the log, while shadowy forms of blue sharks lurk in the distance. A loggerhead turtle breaks the surface nearby to breathe and with ancient dewy eyes surveys the log for a moment.
Unknown to the turtle, the log carries a satellite beacon that will guide a purse-seine boat to this spot a few days later.
Nobody knows exactly why fish gather around floating objects in the open sea. It cannot be because the objects provide protection for the schools of baitfish that gather around them, for how much protection can a log or a mat of floating vegetation provide? Perhaps it is simply because they provide some reference point, however slight, in this boundless, seemingly featureless liquid world. Purse-seine boats have long sought out floating logs and other objects around which to set their nets, knowing that catches will be good.
It would not be long before somebody thought of putting their own logs into the sea, but how would they find them again in the trackless waters of the high seas? Far-sighted fishery scientists of the 1960s, whose imaginations concocted the idea of using submerged nuclear reactors to create upwellings, thought of a way. In 1964, just seven years after the first artificial satellite, Sputnik I, was launched, they suggested attaching satellite-positioning beacons to logs that would float for a week or two, concentrating fish before the purse-seiners returned for the bounty.
In today's electronic age, the technology they imagined is reality. Purse-seine boats now seed the ocean with veritable forests of floating decoy logs and other fish-aggregating devices to bring together scattered shoals of fish. When they return, they scoop up the fish with ruthless efficiency, taking with them turtles, sharks and dolphins— whatever happens to be there.
For some reason, logs preferentially attract juvenile tuna, so their take even of the target species is wasteful. By catching young tuna before they reach adulthood, purse-seiners forgo much higher catches for themselves later, and they are also denying these tuna the chance to reproduce, putting future catches at risk. Where once the vast canvas of the sea was great enough for fish to lose themselves in, escaping capture, today even the high seas afford little refuge. New technology has given old fishing methods a far more lethal edge.
The fishing industry has been lent a hand in the search for fish from some surprising quarters. Sonar depth sensors and fish finders were first introduced in the 1930s but were much improved during the Second World War. They work by beaming pulses of sound into the water below the boat and recording the echoes from the seabed and any shoals of fish in between.
Sonar was further developed during the Cold War when submarines skulked in foreign waters. The fishing industry gained an unexpected dividend when East-West relations improved and military technologies were declassified. Apart from enhanced fish-detection capability, sonar is now used to create visual images of the structure of the bottom. Modern multibeam sidescan sonar equipment can map the seafloor in exquisite detail. In just a few weeks, a ship fitted out with this equipment can map hundreds of square kilometers of the bottom, revealing every crease, wrinkle and boulder.
Geologists have adopted the technology with great enthusiasm, embarking on a mapping spree not seen since the 19th and early-20th centuries when cartographers systematically mapped the contours of land. In the United States, for example, the U.S. Geological Survey is publishing maps that give fishers a new look at familiar terrain, allowing them to pick out previously unsuspected seamounts and canyons.
Coupled with high-precision global positioning systems, another part of the peace dividend from the end of the Cold War, fishers can now land hooks or drag nets through places that were much too risky to fish in the past, penetrating deep into the ocean's last refuges from fishing. Where previously nets were almost invariably lost, catches can be taken in relative safety.
The large catches yielded from these former de facto fishing refuges make it worth the residual risk. A Gulf of Maine fisherman describes the benefits new technology brought him:
This stuff has turned the ocean into a glass table. The stuff's so good you can find [some pinnacle], which would be completely surrounded by cod—cod just about clinging to it—and which before you would have steered clear of for fear you'd lose your net, and you can fish it so closely, going around and around, that you can pick virtually every last fish off the thing.
Not surprisingly, the fishing industry is impatient, wanting seabed maps faster than government agencies can produce them. Private companies are weighing in, selling the secrets of the seabed for profit. For a price, they will map the seabed wherever a captain desires.
Most fishing vessels carry their own bottom-imaging devices these days, albeit less sophisticated ones than advanced side-scan sonar. The bridge of a modern fishing vessel more closely resembles the cockpit of a jumbo jet than that of a boat.
Sonar systems onboard show the shape and texture of the seabed in real time, allowing fishers to choose the best fishing sites and avoid obstructions. New computer software allows captains to “fly” trawl nets, with net-based sensors beaming up data on the spread of the net, its fullness and what lies ahead of it. Some nets are equipped with powered units to adjust gape and trim. Skilled captains can steer their nets toward shoals of fish they can “see” as if they were riding on the net itself.
The "Flying Dutchman" as a Fishing Net
It isn't just the relentless intensity of fishing today that is harming the oceans, it is the destructive and wasteful way in which we fish. In landing 80 million tons or so of wild fish a year, fishers throw away another 16 to 40 million tons.
The uncertainty over the exact amount discarded is because few countries consider it important enough to warrant the expense of collecting accurate figures. The best guess that scientists have come up with is that a quarter to a third of all animals caught are simply tossed back into the sea, most of them dead or dying.
If statistics on discards are hard to find, estimates of how much is killed below water but never brought on deck are even more difficult to come by. Videos of bottom trawls in action, and study of the seabed after the passage of trawls, show that many animals that escape capture are injured or killed.
Ghost fishing by lost gear can also be severe. Michael Dwyer joined a hellish deep-sea gill-netting trip to northern Labrador in 1998. He wrote of his experience in Sea of Heartbreak, the most chilling account of destructive fishing I have ever read. His descriptions both reveal the indiscriminate waste of fish killed as bycatch and highlight just how much fishing gear is lost to continue killing fish unseen at the bottom of the sea:
The past four days and nights offshore had not been profitable. We had spent endless marrow-freezing hours on the lurching bridge searching for buoys in the foulest of conditions—and yet more hours toiling to pull gear that yielded little number one turbot but seemed full to bursting with other sea creatures, including a dozen ground sharks and what appeared to me to be squadrons of manta rays.
To add salt to the wounds, one fleet [of nets] had broken free after we had battled back 20 nets. We lost 50 nets, and we spent the rest of the day in a futile attempt to find the southern end.
Another fleet parted on the very next haul. Wayne knew the webbing was snagged on the bottom. The wheel spun around another ragged end, and suddenly 50 nets were gone.
The fishing gear is designed, made and set in a deadly efficient way. Set like a fence across the bottom, the webbing eventually fills with sea creatures and “lies down.” Crabs, the scrubbing action from contact with the seafloor and time serve eventually to consume and break down the sea creatures. When this happens, the nets rise up again and fish indiscriminately. They fill up and lie down, over and over, forever. Stories have been told of draggers finding old, lost gear, and the nets are filled with skeletons of every kind. As horrible as it is, it's legal—and it's a common form of commercial fishing.
Dwyer describes the horror of pulling in a net that had been left out too long:
I tried not to let the smell of rotting fish and sea sponges make me too sick. Often the floodgates clogged with the dead. The picking table piled high with tangled webbing. Production was at a snail's pace. We had rock crabs by the hundreds, chimaera [also called rabbit fishes] by the score.
Parts of the rocky bottom came round the wheel with the nets— hard coral fragments in all their colors, shades, shapes and sizes. Every piece had to be picked out because even a small fragment could tangle up three or four nets as they were being set. It was a sea of heartbreak.
At the end of the trip, the fishers simply threw all their used gillnets into the sea. While this practice was illegal, it was unwittingly encouraged by Canadian government subsidies that gave fishers nets almost for free.
A recent study of deep-sea fishing in the North Atlantic for sharks and monkfish suggests that some 3,600 to 5,400 miles of gillnet are in constant contact with the bottom there. Over 780 miles of nets are lost or discarded every year—nets left to fish on and on, unknown and unattended.
An Immodest Proposal
We cannot return the oceans to some primordial condition absent of human influence. But it is in everyone's interest to recover some of the lost abundance of creatures in the sea. Fishers, seafood lovers, snorkelers and scuba divers are obviously high on the list of beneficiaries, but everybody has a stake in healthy oceans.
For generations, people have admired the denizens of the sea for their size, ferocity, strength or beauty. But we are slowly realizing that marine animals and plants are not merely embellishments to be wondered at. They are essential to the health of the oceans and the well-being of human society. Diverse and intact marine ecosystems are more productive, healthier and more resilient than degraded ones.
Overfishing is an important contributor to many of the adverse changes to oceans and coasts in recent times— dead zones, toxic algal blooms, flesheating microbes, beaches covered with slime and jellyfish explosions, to name a few. Today, we are paying the price for over a hundred years of negligence in ocean conservation. We need to restore the abundance of sea life and give marine ecosystems a chance to repair themselves if the planet is to remain healthy.
This book is not a requiem for the sea. We still have time to reinvent the way we manage fisheries and protect life in the oceans. I am optimistic for the future. The creation of national and international networks of marine protected areas, together with some simple reforms in the way we fish, could reverse this run of misfortune.
It will take concerted public pressure and political will to change attitudes that have become entrenched over hundreds of years. But if today's generations do not grasp this opportunity, tomorrow's may not get the chance because many species now in decline will have gone extinct.
Pew's Environment Group works to preserve the biological integrity of marine ecosystems, focusing primarily on efforts to curb overfishing, reduce bycatch and prevent the destruction of marine habitat. For information on the group's initiatives in marine policy, conservation and science, visit www.pewtrusts.org and click on Protecting Ocean Life.
Callum Roberts is a marine conservation biologist at the University of York, England. He studies protected areas and has assessed the rapid recovery of fish and other animals after protection. His findings show the scale of human impact on ocean wildlife and the ability of protected species to recover.
In 2000 he was awarded a Pew Fellowship in Marine Conservation to study the design of reserves. The award supported him in the early stages of writing the book excerpted here. For more on the fellowship program, visit www.pewoceanscience.org and then click on Pew Fellows.