In the introductory chapter to his book, Dr. Bakun wonders aloud whether mainstream fisheries science, "like the now-extinct dodo birds of Mauritius", has followed an evolutionary path into a feedback trap of over specialization. Of most concern is the continuing, seemingly incredible, restriction on the use of ecological and environmental information in our attempts to understand and model fish population dynamics. Luckily, Bakun notes, we are not dodo birds. He expresses optimism that our science will expand in breadth, and that breakthroughs will come though the use of pattern recognition, one of the principal tools of the historical/narrative scientific method (Gould 1989).
This is a wide-ranging, highly individualistic treatise on the practice of fisheries oceanography. It is unconventional both in its structure and content and I think it will evoke (as is no doubt the intention) strong responses from readers with an interest in the subject matter. The book does focus extensively on the subject matters and regions of the author’s experience: eastern boundary currents, upwelling domains, the California Current, and small pelagic fisheries. This is, of course, perfectly understandable, and Dr. Bakun has strived and succeeded in including a great deal of other interesting material. The book is well written; the author has a knack for story telling in both the scientific and personal stories he relates. I laughed out loud reading his account of a heavy rainstorm he encountered deplaning in a small city in Peru in 1981. While Dr. Bakun raced for cover, everyone else dashed to the open tarmac where they started dancing: heavy rainfall was unknown to small children and a rare event for most residents. The following year began a string of strong El Niño events, during which torrential downpours in this region of Peru are characteristic.
The book comprises fourteen chapters, many of which are intriguingly titled. The first four chapters lay the basic outline for what follows. Within these chapters, the author discusses the limitations of modern fisheries science, suggests we employ a more comprehensive methodology, provides examples (in Chapter 2, "Teasers") of marine ecology puzzles he feels are best examined by way of the historical/narrative method, and covers a few "basic aspects of the ocean system." The topic at hand changes rapidly in these introductory chapters, moving from the purely physical to purely biological to the linkages between the two.
The most consistent and rewarding part of the book is chapters 5-7 where Dr. Bakun expounds upon his views of how environmental control is exerted over marine populations, namely through the triad of processes he terms "enrichment", "concentration", and "retention" acting on critical life stages. While much of the material in these chapters is classic physical oceanography, it is portrayed in a clear manner with exceptionally well-designed graphics to illustrate the often counter-intuitive relationships between winds and wind-driven water movement. The basic equations of fluid dynamics are confined to a ten equation appendix, where they are referenced in the verbal description of the two dominant components of the ocean flow field: Ekman transport and geostrophic flow. Dr. Bakun has done us a justice by presenting these fundamental, yet often poorly understood (by biologists), processes that are key to recruitment dynamics in the ocean.
Given the recent plethora of climatic and ecosystem wide "regime shift" studies, (e.g., Brodeur and Ware 1992, Beamish and Bouillon 1993, Francis and Hare 1994, Polovina et al. 1994), Chapter 8, titled "Long-Distance Connections" is a particularly timely summary of global-scale climatic processes and how vastly separated regions can experience synchronous variability. The material is quite unlike anything most fisheries-oriented marine scientists will have encountered in course work or popular literature, but I urge those interested in details of the emerging regime-shift paradigm to give this chapter a close read. Another contemporary issue addressed in this chapter concerns the relationship between variations in strength of the winter Aleutian Low pressure cell and El Niño episodes. While Dr. Bakun states matter of factly that the two are directly connected, the issue is not that cut and dried. There is much current work on the nature of the climatic link between the Pacific tropics and subtropics (Kumar et al. 1994, Latif and Barnett 1994, Deser and Blackmon 1995, Zhang et al. 1996).
In the remainder of the book, with the exception of the misplaced Chapter 11 (discussed below), Dr. Bakun puts his historical/narrative method to work. He alternates among a variety of topics, including basic biological processes such as reproduction and migration, analyses of variability in specific fish populations such as the Antarctic krill and Guinea Current triggerfish, and the importance of El Niño to Pacific fisheries. Indeed, one of the most valuable assets of this book is its rich set of case studies, ideal for upper-level undergraduate or first-year graduate fisheries courses.
One of the chief merits of this book is its use of the historical/narrative method of science. It is a bold and brash display of one person’s ideas on a way of conducting scientific investigation and drawing conclusions from that work. Indeed, there is nary a statistic, likelihood, or Monte Carlo simulation to be found in the entire book. To this reader however, this also becomes the chief fault of the book. Rather than showing by example, I would have preferred that Dr. Bakun include a methodological chapter early in the book on the historical/narrative method and its proper use. There are comments on the method scattered throughout the book, and we are treated to an extensive discussion on what not to do. For instance, the misplaced Chapter 11 - which interrupts the narrative flow and belongs in a methodological chapter such as that requested above - includes a subsection on the dangers of correlative approaches and statistical interpretation problems related to autocorrelation. He then advises adoption of nonlinear techniques such as those utilized by Cury and Roy (1989) in formation of their optimal environmental window hypothesis. Dr. Bakun believes that linear statistical methods have been abused by generations of fisheries scientists (and he’s right), but wait until he sees what can be done by amateur statisticians armed with a set of non-linear statistical tools.
I am of the belief that linear models, properly used, do have a place in the fisheries oceanographer’s work. For example, to identify recurrent climatic patterns (and pattern recognition is one of the stated goals of the book), climatologists have long used a variety of multivariate techniques including principal component analysis (e.g., Preisendorfer 1988) and cluster analysis. The inconvenience of autocorrelation in environmental and biological data can be turned to an advantage by mastery of the linear tools collectively referred to as time series analysis (Box et al. 1994). In short, our best approach is a combination of the historical/narrative method and judicious use of statistical and simulation/modeling. This is likely to provide clearer advances in scientific knowledge and foster acceptance from those whom still need convincing that fish live not in a random, but a complex, dynamic and important, environment. Accepting, and acting on, this long-disputed point, is crucial if we are to improve our current fisheries population dynamics models.
References
Beamish, R. J. and D. R. Bouillon. 1993. Pacific salmon production trends in relation to climate. Can. J. Fish. Aquat. Sci. 50: 1002-1016.
Box, G. E. P., G. M. Jenkins, and G. C. Reinsel. 1994. Time series analysis: forecasting and control. 3rd. ed. Prentice-Hall, Englewood Cliffs, NJ. 598 p.
Brodeur, R. D. and D. M. Ware. 1992. Interannual and interdecadal changes in zooplankton biomass in the subarctic Pacific Ocean. Fish. Oceanogr. 1: 32-38.
Cury, P. and C. Roy. 1989. Optimal environmental window and pelagic fish recruitment success in upwelling areas. Can. J. Fish. Aquat. Sci. 46: 670-680.
Deser, C. and M. L. Blackmon. 1995. On the relationship between tropical and North Pacific sea surface temperature variations. J. Climate 8: 1677-1680.
Francis, R. C. and S. R. Hare. 1994. Decadal-scale regime shifts in the large marine ecosystems of the North-east Pacific: a case for historical science. Fish. Oceanogr. 3: 279-291.
Kumar, A., A. Leetmaa, and M. Ji. 1994. Simulations of atmospheric variability induced by sea surface temperatures and implications for global warming. Science 226: 632-634.
Latif, M. and T. P. Barnett. 1994: Causes of decadal climate variability over the Pacific/North American sector. Science 226: 634-637.
Polovina, J. J, G. T. Mitchum, N. E. Graham, M. P. Craig, E. E. DeMartini, and E. N. Flint. 1994. Physical and biological consequences of a climate event in the central North Pacific. Fish. Oceanogr. 3:15-21.
Preisendorfer, R. W. 1988. Principal component analysis in Meteorology and Oceanography. Elsevier, Amsterdam., 425 pp.
Zhang, Y., M. Wallace, and N. Iwasaka. 1996. Is the climate variability over the North Pacific a linear response to ENSO. J. Climate 9: 1468-1478.
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