A flurry of reports over the last decade has brought overfishing to the fore of scientific awareness and policy debate. Yet the scope and magnitude of fisheries-induced changes on the world's oceans remain poorly understood and under-appreciated, in large measure because of the lack of rigorously obtained scientific data from earlier times, an intellectual myopia caused by regional or taxon-specific interests, and a psychological phenomenon known as “shifting baselines”: the tendency for people to define pristine nature as nature the way they first saw it, not the way it was in the beginning. The Unnatural History of the Sea offers a larger and longer-term perspective on whaling, sealing, and fishing, tracing the significant impacts of these activities back a millennium or more in Europe, and hundreds of years elsewhere, as European adventurers became competent seafarers and began probing the world's oceans.

The recognition of long-standing human impacts on marine species and ecosystems is not new—witness Mark Kurlansky's nonfictional bestseller Cod or Jeremy Jackson and colleagues' Historical Overfishing and the Recent Collapse of Coastal Ecosystems. The Unnatural History of the Sea is nonetheless groundbreaking in that it draws together accounts of remarkable change in various species and in most of the world's major marine ecosystems over the sweep of recorded history. Some readers will no doubt quibble with the book's various details, and a few may take strong exception to its essential conclusions, arguing that proper documentation is lacking and that the picture painted is therefore alarmist and extreme. In my mind, however, the book makes a forceful case, supported by diverse evidence from various species and ecosystems, that modern oceans have been so vastly altered by the overexploitation of whales, seals, and fishes as to be barely recognizable semblances of their preexploitation states.

The book is organized into three sections. The first is a view of the more ancient past, including depictions of the abundance of various fish and marine mammal populations in early Renaissance Europe or at the time of their discovery elsewhere by European explorers, and explanations of the historical events that led to these discoveries. As scientific data of present-day standards are lacking from early times, the measures of abundance are instead obtained from the written narratives of early adventurers—ship captains, privateers, and various government officials. Such accounts are necessarily of mixed quality and sometimes-uncertain reliability, depending on the whims, motivations, objectivity, and integrity of those who wrote them. Despite these shortcomings, it is difficult to imagine that reports of such richness, recounted independently by so many sources from so many places, do not fairly portray the oceans as the early fishers saw them.

The book's second section focuses on the modern era of industrial exploitation, a period extending from roughly the early to mid-19th century to the present. The author takes us from a time of widespread belief in an inexhaustible sea through the declines of such sundry species and ecosystems as the great whales, European coastal and shelf fisheries, Atlantic cod, eastern North American estuaries, coral reefs, and, most recently, the remote open ocean and deep sea. The historic narratives that accompany these first two sections provide fascinating insight into the recent history of the oceans and interesting new perspectives on important figures from the history of science. For example, many readers will no doubt be surprised to learn that Thomas Huxley's powerful intellect and force of personality came to bear not only in championing Darwin but also in denying 19th-century concerns over the destructive effects of bottom trawling.

The book's final section makes two forceful arguments—first, that fisheries have now penetrated the deepest and most remote parts of the ocean, thus exhausting stocks nearly everywhere and driving living marine resources far below any reasonable conception of sustainability; and second, that a fundamentally different approach to fisheries management and ocean conservation will be needed to fix the problem. Although there will be grousing over the details, I doubt that many would disagree with the first of these arguments. In marshaling support for his second argument, Roberts reminds the reader that traditional fisheries management has repeatedly failed, and points out that even greatly reducing fishing will be insufficient to restore habitats that have been damaged or transformed by bottom trawling. His proposed solution is to manage ocean resources around a global network of marine reserves and protected areas. Such a radical departure from the status quo is bound to stir controversy—the stakes are high, and radical change from traditional views is always slow in coming. Regardless of where one stands on fisheries management, this book provides a great service to society by forcing the issues into the arena of public visibility and debate.

The Unnatural History of the Ocean is essential reading for everyone with an interest in the ocean, and I highly recommend it to anyone with a general desire to learn more about the world. You will be captivated by the graceful prose, intriguing historical vignettes, and startling revelations. No matter how much you think you know about fisheries and the state of our oceans, this book will leave you with a renewed appreciation for what has been lost through the exploitation of living marine resources, a heightened awareness of the present state of the oceans, a sense of urgency for the need for action, and a feeling of some hope in the proposed solutions. My only disappointment is over the author's failure to consider whether any of this matters very much, given the world's limited capacity for food production and the closely related question of how we are to feed the large and growing human population in a sustainable way. In fairness, the same criticism could be leveled against most other modern agendas and proposals for conservation action. Nonetheless, this book's underlying messages are certain to become part of the language of the future. Read it and consider these messages or be left behind.