"The Unnatural History of the Sea"

May 1, 2009

BookShelf

Reviewed by CHRISTINE HEINRICHS

It's no revelation that the world's oceans have been overfished.

Callum Roberts documents the extent, duration and effects of the problem in The Unnatural History of the Sea, winner of the 2008 Society of Environmental Journalists' Rachel Carson Environment Book Award. The book tells a saga of technological advances that have allowed the plundering of the world's fisheries to accelerate.

In his book, Roberts points out a basic flaw in the baselines often used to evaluate the extent of overfishing. Relying on evidence solely from recent history — the past hundred years or so — causes us to overlook how much abundance has been lost, he says.

"I find that few people really appreciate how far the oceans have been altered from the pre-exploitation state, even among professionals like fishery biologists or conservationists," he writes in the book's preface. "A collective amnesia surrounds changes that happened more than a few decades ago, as hardly anyone reads old books or reports. The worst part of these 'shifting environmental baselines' is that we come to accept the degraded condition of the sea as normal."

To learn what the oceans and rivers once contained, Roberts examines the writings of Roman writers such as Caesar, Pliny the Elder and Ausonius. In the first century AD, Pliny described fish in the River Padus — apparently sturgeon— that reached a weight of half a ton and had to be dragged from the water with teams of oxen. Archeological records reflect the decline of sturgeon as a food source in the Baltic region: from 70 percent of fish eaten in the eighth century to 10 percent of the fish eaten by the twelfth century. The bones also revealed that sturgeon were becoming progressively smaller. By the thirteenth century, England and France passed laws reserving sturgeon for use only by monarchs. The British law remains in effect.

By researching the historical record, Roberts establishes a richer baseline than the ones that have crept into acceptance. And what a story those documents tell! Think of oceans roiling with fish, sea beds clogged with the shells of oysters and mussels, inlets crowded with hundreds of otters. "Seeing the world through the eyes of early travelers helps us to better understand our own environment and gives us the impetus to find better ways to protect it," he writes.

Archaeological evidence shows that the depletion of fish stocks began as early as the 11th century. Technological changes made it possible to fish further and more efficiently. Now it is possible to harvest nearly every fish in the ocean. Trawl gear, first used in 1376, was immediately recognized as destructive and wasteful. Despite anger about its use, fishermen have continued to trawl because it is such an efficient method to scoop up large amounts of fish.

Roberts acknowledges that some areas have been closed to trawling, notably close to coasts, but in general, "trawling grounds are defined simply as any place a fisher is willing to put down a trawl." The cameras mounted on underwater Remotely Operated Vehicles can now document the physical effects. Describing seamounts off the Australian coast after a few decades of orange roughy trawling, Roberts writes that they were "shocking in their sterility: exposed stark vistas of bare rock, criss-crossed with the scars of repeated trawl passes."

As technology becomes more efficient and more fish can be taken from the sea, there's a predictable progression. First the large fish of high-value species are taken. When those are gone, fisher- men move elsewhere or switch to other species. They proceed down the food web, taking ever smaller and less desirable species. Roberts quotes Daniel Pauly of the University of British Columbia, who said, "We are eating today what our grandparents used as bait." Today, fishermen pursue prawns, crab and lobster where they used to chase cod. "Pauly warned that in due course we will end up consuming plankton directly, drawn from seas without fish," Roberts writes.

As ships get bigger and are equipped with more sophisticated technology, they can chase ever-declining stocks and continue to make a profit. Scarce supply drives the price up, and being the first to take the last fish works economically for the fisherman, at least in the short term. "Where there is no restriction on access people will pile into the fishing industry as long as there is profit to be made," Roberts writes.

And so it goes: the largest mammals and fish, whales, tuna, grouper, skate, sharks, are fished down, in many cases below the target levels for maximum sustainable yield. "Today, many fish stocks languish at between a tenth and a thousandth of their unexploited numbers," Roberts writes. For example, the cod population on the Grand Banks is now less than one percent of its unexploited population size, he says. "If we stick to that manage- ment paradigm (of unsustainable exploitation of the sea), I am convinced that marine life will continue its long slide toward jellyfish and slime," he writes. The loss of fish down the food web impacts sea birds and mammals that feed on them. And lost and damaged nets and gear float free, continuing to catch fish, amphibians and mammals whose deaths will never even have the justification of becoming food. Over 780 miles of gill nets are lost or discarded every year – ghost nets that kill in perpetuity.

Roberts is undaunted in his conviction that it's not too late to save the oceans. He outlines six points to improve fishery management: reduce the amount of fishing; cut politicians out of the process; limit where, how long and with what gear a vessel can fish (such limits have been used in the U.S. in many fisheries but have been slow to catch on in Europe, he says); use the best available fishing technology to reduce bycatch; and ban or restrict the most damaging fishing gear.

Combine those regulatory measures with protection for 30 percent or more of the oceans and they could return to abundance, Roberts says. Not to pristine conditions – the losses have irretrievably altered many ecologic relationships – but to a new baseline of healthy fish and ocean life of all kinds. "The public is ready for such a change in thinking," he writes.

Right now, only three-fifths of one percent of the oceans is off limits to fishing. But in January, the National Oceanic and Atmospheric Administration established eight new marine protected areas encompassing a total of 529 square nautical miles in south Pacific waters to shield deep-water fish species and their habitats from fishing. In the Arctic, the North Pacific Fishery Management Council banned all commercial fishing in U.S. waters from north of the Bering Strait and east to the Canadian border in February. That decision was reached to allow time to evaluate the effect of ocean warming on fish stocks including Arctic and saffron cod and snow crab. The oceans are not lost and we can be grateful to Callum Roberts for bringing their condition into such vivid perspective.

Christine Heinrichs is a freelance writer on California's Central Coast. Her second book, How to Raise Poultry, on raising traditional breeds in small flocks, was available in April. She's an Elephant Seal docent at Piedras Blancas.