The Unnatural History of the Sea
Callum Roberts
2007, Island Press

Callum Roberts, a respected marine scientist, recounts the unseen history of human impact upon the oceans and their inhabitants. He begins by pointing out that ruthless exploitation of natural resources by the fishing industry began as far back as the 11th century in medieval Europe.

Early visitors to North America marveled at the wealth of wildlife, the tall stands of virgin timber, the clear-running streams filled with shoals of fish. Europeans had long since depleted their own freshwater fisheries, dammed their streams for mills, and cleared forests for farmland, allowing soil erosion to muddy all the rivers and streams of the continent.

Roberts describes a long history of untrammeled over-exploitation of natural resources, with technological innovations allowing for ever more efficient harvesting of the ocean’s wealth. Nearshore fisheries quickly became depleted, and fishing fleets had to venture ever farther from home to find fish in commercial quantity. A result of centuries of overfishing is that the size of fish has greatly diminished, as older fish are quickly harvested, breeding populations are depleted, and smaller and younger fish taken to market.

A particular development in fishing technology that has literally reshaped the environment of the ocean floor is the trawl, which scrapes the seabed with weighted nets to scoop up all living things. Over time, trawls have become more efficient; with the advent of steam power in the eighteenth century, it was possible to trawl anywhere, anytime, without concern for wind and tide. The floor of the North Sea has been scraped clean of flora that once sheltered a vast variety of fish and other sea life; Roberts estimates that 100,000 square miles of the North Sea is scraped by trawls an average of twice a year.

The great excitement attending the “discovery” of the New World was that it offered heretofore untapped wealth of natural resources. Predominant among those resources were the fish of its waters. Europeans quickly moved in to harvest that undersea wealth. What happened in Europe happened in North America: as fish stocks were depleted in one area, the fleets moved on to other areas. As one species became fished out, the fishing industry harvested other species.

Throughout this carefully reasoned and thoroughly documented study, Roberts’ theme continues to echo: we have systematically wiped out species after species of fish; the undersea environment has been scarred and depleted by the continuing use of massive trawling equipment; the “bykill” – unwanted creatures caught up in trawl nets and discarded – has depleted even species that are not wanted for food; and discarded fishing equipment, such as miles and miles of purse seine nets left to float in the sea – are entrapping and killing vast amounts of fish, sharks, turtles and other animals.

The book closes by proposing a new approach to fisheries management. Rather than “managing” by allowing fish stocks to be overfished, Roberts suggests closing large areas of ocean (perhaps as much as 30%) to fishing altogether. This allows species to recover, grow to maturity and breed more successfully. It has been demonstrated in small areas that such closings actually increase the take of fisheries outside the area; the restricted area serves as a nursery which feeds fish into the surrounding areas where they may be taken in a sustainable way.

This is a fascinating book, telling with compelling detail a tragic story of ecological destruction carried out far from the awareness of most people. But it is only by facing the reality of the mistakes of the past that we can move forward to create a new way of living in the natural world, one that recognizes the need to conserve and protect our natural “capital” rather than heedlessly expending it all.

David Yarian, Ph.D.

The Unnatural History of the Sea Callum Roberts 2007, Island Press

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