Matthew McKenzie

The history of ocean resources: modeling cod biomass using historical records

Managing the remnants of the oceans resources is a critical issue worldwide, but evidence for what constitutes a healthy fish population remains controversial. Here, we use historical sources to understand ecosystem trends and establish a biomass estimate for a key marine species prior to the industrialization of fishing. Declining trajectories have been described for predatory fishes and complex coral reef systems globally, but few numerical estimates of past abundance exist. We combined historical research methods and population modeling to estimate the biomass of cod on Canadas Scotian Shelf in 1852. Mid 19th-century New England fishing logs offer geographically specific daily catch records, describing fleet activity on fishing grounds with negligible incentive to falsify records. Combined with ancillary fishery documents, these logs provide a solid, reliable basis for stock assessment. Based on these data we estimate a biomass for cod of 1.26 × 106 mt in 1852 – compared with less than 5 × 104 mt of ...

Conservation implications of omitting historical data sources: response to Baisre

Historical ecology has made important contributions to conservation biology, broadening our understanding of long-term changes to species and ecosystems, of their structure and function before pervasive human impact, and of the possibilities for recovery and restoration (Rick & Lockwood 2012). Its research model relies on archaeological and historical records—which can be incomplete—and often makes use of sources that are imprecise by modern ecological standards. For these reasons, Baisre (2013) argues that previous historical ecology research on Caribbean monk seals (Monachus tropicalis) was flawed. He re-examined historical and archaeological records previously compiled by McClenachan and Cooper (2008) and others and concluded that rather than a ubiquitous predator in Caribbean reefs, monk seals were “naturally rare,” persisting only “as a small fragmented population” at the time of first European contact. However, Baisre’s conclusion results from a limited re-examination of historical documents and faulty assumptions and has implications for historical ecology and conservation biology more broadly. Here, we build on a previous discussion (McClenachan et al. 2010) to address Baisre’s problematic approach. We limited our comments to two issues with broad application to future historical ecology research. First, central to Baisre’s conclusion is his assessment of the historical record as insufficient, particularly with respect to a regional or international trade in seal oil, a commonly cited driver of population decline and ultimate extinction. Although sailors and natural historians in the early decades of the 18th century described a substantial hunt of Caribbean monk seals in certain locations—such as up to 100 seals killed per night in the Bahamas (Sloane 1707)—Baisre discounted these written accounts, claiming that a seal trade should have left a more complete historical record. As a result, he concluded that seal populations were too rare to support exploitation. However, this conclusion is based on a limited re-examination of historical documents and fails to consider the variety of sources that provide insight into past change. In particular, Baisre considered only published documents that could be found in libraries or online and did not distinguish between narrative accounts and official documents generated by colonial settlement and trade. As a result, he overlooked important unpublished government documents, which are kept in archives in their original form and not typically reproduced for publication. In contrast, McClenachan and Cooper (2008) visited more than 20 archives to collect historical source documents. These sources included British colonial shipping records that document trade in seal oil and skins (Fig. 1) in the same location and period where natural historians (Sloane 1707) and sailors (Bruce 1782) describe hunting seals for oil. Together, these sources counter Baisre’s conclusion of historical rarity of Caribbean monk seals and underscore the need for a thorough review of historical documents. Second, Baisre dismisses large quantities of anecdotal data, or narrative historical sources, stating that they do “not meet the basic requirements of ordinary zoological samples,” thus introducing a strong bias of what constitutes reliable observation. Although Pauly (1995) argues for the use of anecdotes to evaluate ecosystem change, the term anecdote connotes a lack of credibility in some contexts (Haggan et al. 2007). This is problematic because much historical ecology research requires narrative historical sources to document species’ occurrences. Indeed, most of what is known about Caribbean monk seals after European contact derives from descriptions left by sailors, settlers, and natural historians. Baisre dismisses an account by Hans Sloan, a respected 17th century scientist and the founder of the British Museum, and seven others describing a seal oil trade. Likewise, Baisre rejects observations of seals across the Caribbean basin, including the Lesser Antilles, South America, and Florida and concludes that seals were found only on “small islands and isolated banks.” Excluding historical sources on the basis of modern biases erodes the research process and can fundamentally alter conclusions. Failing to conduct a thorough review of historical sources and to incorporate anecdotal information can lead to misleading results and have important conservation implications. In this case, Baisre’s limited re-analysis of historical sources led to the conclusion that monk seals were naturally rare and therefore ecologists should not consider the possibility that Caribbean reef ecosystems were productive enough to support abundant mesopredators. This, in turn, lowers expectations for conservation and restoration of Caribbean reef ecosystems. As well, a judgment of natural rarity can be used to support the argument that the extinction of Caribbean monk seals was primarily the result of a natural process rather than anthropogenic. Ultimately, a judgment of natural rarity reduces the significance of the extinction event, because losing rare species is less troublesome than losing species that were historically abundant.

Book Review: Shaping the Shoreline: Fisheries and Tourism on the Monterey CoastChiangConnie Y., Shaping the Shoreline: Fisheries and Tourism on the Monterey Coast. Seattle and London: University of Washington Press [www.washington.edu/uwpress], 2008. xviii + 282 pp., maps, photoplates, illustrations, notes, bibliography, index. US

officials limited certain types of licences to whites as a way of encouraging more nonnative and non-Asians to settle in the more northerly areas of the province. These policies came at the expense of Aboriginal and Japanese fishers who were, by the late nineteenth century, the dominant participants in the north coast industrial fishery. The government lifted these racialized restrictions in the 1920s, but native fishers continued to face other social and economic barriers to full participation in the fishery. While Indian Affairs officials occasionally tried to defend native fisheries, and Aboriginal leaders themselves made demands for the right to fish, the Department of Marine and Fisheries ideas generally prevailed. In the meantime, natives in British Columbia were left with small reserves and increasingly limited access to fish. Besides revealing the ways that Aboriginal people in British Columbia experienced the land and fisheries issues, this story also reveals the unevenness and contradictions of the colonial state. While Indian Affairs assumed continued native access to fish was vital so they would not become a burden on the state, the Department of Marine and Fisheries, with an interest in promoting white settlement and participation in the salmon canning industry, pushed fisheries policy in a different direction. As well, these two agencies intersected with capital structures with implications for Aboriginal participation in the industrial fishery. While the latter still needs a more thorough treatment in this time period, Harris quite rightly suggests that a more integrated approach to understanding the historic, legal and economic processes that shaped the experiences of Aboriginal people in this period is essential. Perhaps the books larger potential contributions, however, are the questions it raises about historic recognition by the Crown of native fisheries and their relevance for ongoing discussions over land claims and resource rights. While First Nations groups make claims for access to fish based on a pre-existing Aboriginal right, Harris argues that the words and actions of nineteenthand early twentieth-century reserve commissioners can also be used to document earlier Crown recognition of native fisheries. Moreover, Harris asserts that statements made in a recent Supreme Court case that the Crown never intended to allow special fishing rights for native people are wrong. Although the Department of Marine and Fisheries vision of a limited native fishery prevailed in the nineteenth and twentieth centuries, this book suggests it was never the only vision in the past, and need not be in the future.

35, £19.99, cloth; ISBN 978-0-295-98831-3.

methodological, but by bringing together diverse analyses of climate and fisheries, the book is provocative and likely to stimulate new research. What is missing from this volume is a clear discussion of how to do empirical work on the past to inform future management under changing climate. More specifically, the authors provide little guidance on how to parameterize non-autonomous bio-economic models like the ones in Amasons theoretical essay. Readers without formal training in mathematical bioeconomics, game theory and econometrics will have trouble following the details of this volume. This shortcoming is widespread in fisheries economics and may account partly for fisheries management that fails to incorporate basic economic reasoning. Nevertheless, several essays are quite accessible to non-specialists most notably Hamilton, Otterstad and Ogmundsardottirs and the introductions and conclusions of chapters do not require extensive specialized knowledge. Climate Change and the Economics of the Worlds Fisheries raises as many questions as it answers and clearly points to the need for more work. Considerable research effort in the environmental sciences focuses on climate mitigation policy, while research on adaptation policy is only beginning to emerge. Even under optimistic climate scenarios, some adaptation in fisheries will be necessary, and agencies that fund fisheries research ought to support work in this area. This volume is a useful step, but it will not be the last word on climate and fisheries.