In the icy waters of the Norwegian fjords, Marine Harvest and its Dutch parent company, Nutreco, are engaged in research that is changing the way we eat. (Marine Harvest has since been sold to a Norwegian company named Pan Fish.) Of all the species that humans have domesticated over the past 10,000 years, those living in the sea have been the most difficult to tame. In fact, it’s only in the past hundred years that we have made any headway at all. For the most part, aquatic food production is still governed by the ebb and flow of natural stocks. On land we may be farmers, but in the sea we remain hunter-gatherers.
The scientists at Marine Harvest, though, have a vision of the future of aquaculture (the growth of aquatic species for food) that extends from salmon to fishes as diverse as cod, halibut, and tuna. Yes, tuna: it’s farmed on offshore ranches east of Australia, which are staffed by Aussie “cowboys” who wrestle the fish into boats by grabbing their gills and flipping them onto their backs so they are rendered temporarily immobile. Most aquaculture is a far more sedentary pursuit, however—and much more scientifically intensive.
The investment involved in such enterprises is enormous. Nutreco was part of British Petroleum before being spun off as an independent company in 1994, and its staff work all over the world. It employs dozens of scientific researchers and invests tens of millions of dollars each year in developing better strains of farmed fish. Clearly, such a venture makes sense only if there are profits to be made. And there clearly are: one of the fish pens I visited in Norway contained over $15 million worth of farmed halibut, based on the current market price—and it was a small-scale experimental facility. This is no cottage industry.
Aquaculture dates back a couple of millennia to China, where carp were held in artificial lakes after river floods. These fish, fed a diet that included silkworm feces—an early version of industrial recycling—provided a steady food resource to the growing rural population of China. Similarly, the Polynesian peoples of Hawaii constructed ponds to hold wild fish as a ready source of protein, and medieval Europeans kept carp to meet the demands for fish as the Catholic church increased the number of meat-free feast days (fish, being cold-blooded, weren’t considered to be meat). These farmed carp, however, were eventually replaced by widely available wild-caught cod from the rich banks of the North Atlantic, as improved navigational and preservation techniques created one of the early modern world’s most profitable international trades in agricultural products. Farmed carp were soon rendered unnecessary by a tide of wild-caught cod.
Apart from these sporadic early attempts, aquaculture is largely a phenomenon of the last century. Most of our diet—whether it’s based on wheat, rice, cattle, potatoes, or any of the other non-aquatic animal and plant products humans consume—comes from species domesticated during the early days of the Neolithic Revolution, thousands of years ago. Fish and, to a lesser extent, aquatic plants have mostly been domesticated much more recently—97 percent of them since the start of the twentieth century, and nearly a quarter only in the past decade. Clearly, aquaculture is a new revolution in the making.
I had come to Stavanger to understand more about the way Marine Harvest and other companies are creating this revolution in our food supply, and to learn how and why species are domesticated in the first place. By witnessing a present-day equivalent of the Neolithic Revolution, I began to gain an insight into the events that occurred 10,000 years ago. The revolution in aquaculture over the past century has come about only through carefully applied scientific lessons learned from the study of the basic biology of the species involved. This is very much a high-tech enterprise, and one that makes careful use of information gleaned from fields as diverse as ecology, genetics, chemistry, and agronomy, with a huge financial investment on the part of the companies involved. It turns out that the impetus for this tremendous application of resources is not simply academic—it was born of necessity.
FIGURE 4: PLOT OF DOMESTICATION RATES FOR PLANTS AND ANIMALS OVER THE PAST 10,000 YEARS. ALMOST ALL AQUATIC SPECIES HAVE BEEN DOMESTICATED IN THE PAST CENTURY. SOURCE: SCIENCE 316:382-83 (2007). REPRINTED WITH PERMISSION FROM AAAS.
EMPTY TRAPS
Twelve miles off the coast of Tunisia, an hour’s ferry ride from the industrial city of Sfax, with its phosphate-processing plants and hectic medina, the Kerkennah Islands could be a world away from the twenty-first century. Like many islanders around the world, its people seem to operate in slow motion, their days governed by a slower, tidal clock. The men of Kerkennah are renowned for their fishing ability, and many in the past generation have left home to serve on boats plying the deep waters of the Mediterranean. The ones who have stayed behind, though, carry on a much older tradition.
The islands lie in shallow, grass-filled water that serves as a perfect nursery for red mullet and sea bass. It is possible to walk nearly a mile out from the beach, wading through the warm water until you feel that you could amble across the whole of the Mediterranean. The shallow depth has even meant that at various times during the ice ages, as sea levels rose and fell, the islands were attached to the African mainland. And it is the shallowness of the water that has led the people living on the Kerkennahs to develop a uniquely effective method of fishing.
Taking advantage of their knowledge of the currents running along the shore, as well as the behavior of the fish species they catch, Kerkennian fishermen use neither hooks nor nets. Rather, they trap the fish with a complex and exquisitely well-adapted system that evolved over thousands of years. Using newly cut palm fronds pushed into the sandy bottom in a tight line, they construct a long, water-permeable barrier known as a makhloba, stretched transversely across the prevailing currents. These fish bollards, like plane trees guiding Citroëns and Renaults along the roads of rural France, urge the fish gently into the maw of the working end. The trap itself is a series of ever-smaller chambers, constructed in a similar way from palm fronds. The first is formed by a large barrier at a sixty-degree angle from the main line, the jerby, which forces the fish into a narrow opening. Once they are through this entryway, their fate is sealed; there is no escape. The fisherman call this large, round chamber the charfiya, or “living room,” and the fish that enter find it virtually impossible to discover the entrance again. This is made particularly difficult by the construction of several other openings leading off the living room and into ever smaller chambers, the smallest culminating in an exit into a large basket. These baskets are checked and emptied twice a day by the fishermen.
FIGURE 5: FISH TRAP OF THE TYPE USED IN KERKENNAH, TUNISIA. THE FISH ARE GUIDED INTO THE CHARFIYA BY THE LINES OF PALM FRONDS THAT MAKE UP THE JERBY AND MAKHLOBA, AND ULTIMATELY END UP IN THE TRAPS.
While it may not be as active as other methods of fishing—particularly the intensely destructive bottom dredging used by European fishermen that is now depleting Kerkennah’s stocks—it does leave the fishermen a fair amount of leisure time. Even accounting for the two weeks required to painstakingly construct a new trap, there is still plenty of time for the Kerkennians to stop and smell the roses. In these days of Kevlar-reinforced, titanium-bonded wonder materials, palm fronds are favored because their gentle decay arouses no suspicion in the fish. They need to be replaced more often, but in this case the old ways work best—the fish tend to avoid a synthetic trap. However, as the modern world, with its voracious appetite for seafood, encroaches on them, the natives of Kerkennah are finding it more and more difficult to make a living with their traditional fishing methods. Twenty years ago it was normal to recover 150 pounds of fish from a trap every day; today they are lucky to get one-tenth of that. The younger men who have shipped out on Italian fishing boats send home desperately needed cash to support their families. Others with more of an entrepreneurial bent have opened restaurants and shops catering to the new tourist industry—ironically, an industry fed by people longing to escape from the very world that threatens Kerkennah’s traditional way of life.
Kerkennah’s fishing methods may have been introduced to the
islands by the Phoenicians, the first-millennium B.C. Mediterranean trading empire that built ancient Carthage, just north of Kerkennah where Tunisia’s capital, Tunis, now stands. Similar methods are used off the west coast of Sicily to catch migrating tuna, culminating in the annual spring festival known as the mattanza, where the fish are corralled into smaller and smaller enclosures of nets before being killed with batons. As with the Kerkennian methods, though, the yield has dropped precipitously in the last couple of decades, and now the mattanza is more tourist spectacle than productive fishing technique.
Fishing is currently the only hunting activity carried out on a large scale in the modern world. While the efforts of Marine Harvest and other aquaculture companies are focused on domestication, farming still accounts for only around a quarter of all fish eaten. Most of this production takes place in China, where carp are still raised in freshwater ponds. The majority of fish are hunted in the sea using methods—nets, lines, and hooks—that have not changed substantially in thousands of years. Roughly forty million Americans consider themselves to be anglers, more than three times the number of hunters. Much has changed since we started to grow our own food, around 10,000 years ago, and yet fishing is an activity in which we are still very much in the preagricultural era.
This ancient relationship is changing, though, for the same reasons that the Kerkennian trappers are shifting away from their traditional methods. Overfishing has severely depleted the world’s stocks of wild fish, making it much more difficult to carry out this ancient remnant of our hunter-gatherer past. Since the 1980s, when fishing yields peaked, wild stocks of the major food species have declined precipitously. The rich Grand Banks, off the coast of Newfoundland—which may have led Europeans to North America centuries before Columbus—have been depleted to such an extent that a moratorium was imposed on further cod fishing in 1995. In the North Sea off Britain, the species was declared “commercially extinct”—it no longer made financial sense to pursue it—though it has recently started to recover. According to a recent study in the journal Science, in 2003, 29 percent of open-sea fisheries were in a state of collapse, with a decline in yield to less than 10 percent of what they once produced.
FIGURE 6: THE CURRENT AND PROJECTED LOSS OF SEAFOOD SPECIES, WITH “COLLAPSE” DEFINED AS A DECLINE IN YIELD OF 90 PERCENT OR MORE, COMPARED WITH THE LONG-TERM AVERAGE.
Clearly, something is rotten in the state of the world’s seas—this at a time, ironically, when people are being urged to eat fish for health reasons and fish consumption is actually increasing. The perceived health benefits of omega-3s, the long-chain fatty acids that have been shown to be important in preventing a myriad of modern ills from heart disease to senile dementia, as well as the desire for animal protein with low levels of saturated fats and the medical establishment’s advocating of a lower-calorie diet, have combined to increase the consumption of fish by around a third over the past thirty years in the United States and many European countries, while beef and pork consumption have dropped. Clearly, something has to be done if the supply is to keep growing—which is where Marine Harvest and its competitors come in. By farming fish, we should be able to ensure that the supply will be virtually limitless. Whereas many early attempts at fish farming produced huge quantities of waste and led to the decline of surrounding wild stocks, modern methods are much cleaner and are better for the environment. What is clear from the data, though, is that this final vestige of our hunter-gatherer existence will soon be replaced by aquaculture—out of necessity.
Was the need to shore up a dwindling food supply also the incentive for people in the early years of the Neolithic? In an era long before notions of economic profits, why would hunter-gatherers have started farming? Particularly given the data we saw in the last chapter, suggesting that early agriculturalists lived shorter, unhealthier lives than neighboring hunter-gather populations, explaining the transition becomes much harder. What was the motive for these early agricultural revolutionaries to invest the time and resources to grow wheat and other crops while driving themselves to an earlier grave?
In The Journey of Man, I wrote that collective memory could have played a role. Once the seeds of agriculture were sown, it was likely that there would be no turning back from the new farming order to the old hunter-gatherer ways. “Would you want to make stone tools and hunt for your dinner?” I wrote. Flippant, but probably true. But there was something more: a stick to go with the newly planted carrot. These early agriculturalists probably became trapped in a catch-22 of epic proportions—one that is still playing out today.
THE BURST DAM
The Australian archaeologist Vere Gordon Childe led quite a fascinating life. In his youth he was a Marxist who served as private secretary to the premier of the Australian state of New South Wales, as well as a talented linguist and inveterate traveler. Only later, in the 1920s, did he make the decision to pursue archaeology as a profession, first at the University of Edinburgh and later at the University of London. His early fieldwork was on Skara Brae, in the Scottish Orkney Islands, but his career really took off when he turned his attentions to the early agricultural communities of the eastern Mediterranean.
Childe coined the term “Neolithic Revolution,” and he fully meant it to be taken as a revolutionary transition. All that came before was savagery (which preceded barbarity in the linear progression of his Marxist-influenced view of cultural evolution), and the fruits of civilization arose only after this momentous event. To Childe, the dawning of the Neolithic was the defining point in our history as a species, and he popularized this notion in his books, particularly his widely read New Light on the Most Ancient East and Man Makes Himself, which influenced the general public and subsequent generations of professional archaeologists.
To Childe, one of the key triggers in the onset of agriculture was the abrupt warming experienced in the Middle East at the end of the last ice age. He believed that this warming trend affected the types of plant species growing there, leading some groups of people to begin to cultivate wheat and barley. This successful experiment in cultivation led to an expansion in population and the rise of urban civilization, and gradually, from this Middle Eastern source, Neolithic farmers spread themselves (and their advanced culture) far and wide across the rest of western Eurasia.
FIGURE 7: THE ECOLOGICAL ZONES OF SOUTHWESTERN ASIA AND NORTHEASTERN AFRICA DURING THE LAST GLACIAL MAXIMUM, 18,000 YEARS AGO, AND DURING THE HOLOCENE OPTIMUM, 8,000 YEARS AGO.
While basically correct, this model has since been modified with the reassessment of what happened to the climate at the end of the last ice age. Although the general trend over the past 15,000 years has been an increase in average global temperature, the period between 15,000 and 10,000 years ago was marked by abrupt advances and reversals in the warming trend. It was in this chaotic cauldron that agriculture developed.
Perhaps the best-studied part of this five-thousand-year period is a mini—ice age known as the Younger Dryas, which lasted over a thousand years, from around 12,700 to 11,500 years ago. It is named after the genus of a small plant, Dryas octopetala, found in the tundra regions of Scandinavia, which was replaced by forest in the southern part of its range at the end of the previous ice age but reappeared during the cooler conditions of the Younger Dryas. What led this small ice age plant to suddenly reappear is not completely clear, but the most likely theory is that its reemergence was caused, paradoxically, by the sudden melting of an ice dam in North America.
Now wait, you might be saying—it was affected by an ice dam halfway across the world? This was a very special dam, though. The warming temperatures at the end of the last ice age caused the Laurentide ice sheet we learned about in Chapter 1 to retreat from its foray into Illinois, and the large pieces of ice that remained in North America around 13,000 years ago served to confine Lake Agassiz, a massive body of fresh water located in what is today central Canada. Agassiz was composed of water from much of the rest of the former ice sheet; today’s Great Lak
es are impressive, but this was a monster bigger than all of them put together, larger even than the state of California or the Caspian Sea.
When the ice dam confining the lake melted, the water was released—and rather rapidly, at that. It flowed into the Saint Lawrence River basin and out into the North Atlantic. The flood of fresh water formed a kind of “shield” on the surface of the ocean—fresh water’s density is lower than that of salt water—thus stymieing the Gulf Stream, which brings warmer water from the tropical Gulf of Mexico into the North Atlantic. This natural flow had warmed western Eurasia like a massive radiator since the end of the ice age, and still does. It is the reason why palm trees grow in Cornwall, the southernmost point in Great Britain, despite the fact that its latitude is 50 degrees, the same as Winnipeg in Canada, and nearly 30 degrees north of the Tropic of Cancer. When the influx of fresh water interrupted the Gulf Stream, western Eurasia was plunged back into ice age–like conditions—the Younger Dryas.
While all of this was going on in the North Atlantic, the inhabitants of the Fertile Crescent were getting used to the warmer temperatures. Between roughly 16,000 and 12,700 years ago, the region was warming up and becoming wetter, which led to the expansion of plant species that had formerly been limited in their distribution to mountain valleys, where there were reliable supplies of water. The ready availability of these grasses—the ancestors of wheat, rye, and barley—led some human populations to focus much of their energies on gathering them, since they were a plentiful and calorie-rich food source. The Natufian people, who flourished in the western part of the Fertile Crescent during this period, were largely grain gatherers. And unlike almost all hunter-gatherers who came before, they were sedentary—they lived in small villages.
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