J Mammal Evol (2008) 15:227–229 DOI 10.1007/s10914-008-9076-8

BOOK REVIEW

Fishing Through The Flotsam, An Attempt To Understand The Legacy Of Whaling Whales, Whaling, and Ocean Ecosystems. Edited by James A. Estes, Douglas P. DeMaster, Daniel F. Doak, Terrie M. Williams, and Robert L. Brownell, Jr. Berkeley: University of California Press. 2006. 402 pp., $54.95 (cloth). ISBN-10: 0520248848. Jonathan H. Geisler

Published online: 28 February 2008 # Springer Science + Business Media, LLC 2008

If the purpose of an edited volume is to provide a comprehensive sample of research in a developing field, then the editors of Whales, Whaling, and Ocean Ecosystems should be congratulated in putting together an excellent book. With 31 chapters written by 59 contributors, most, if not all, major perspectives in this field are included. This book also looks great, with original illustrations by Kristen Carlson giving the volume a uniform feel. Chapters in this book are organized into five major sections, and I follow this structure for my comments. Most of the chapters in this book relate to the following question: “How did whaling influence ocean ecosystems?” The Background section includes five chapters that lay the foundation for answering this question by discussing bottom-up versus topdown controls on species. Three chapters, those by Paine, Donlan et al., and Jackson, favor top-down processes and argue that whaling must have had profound effects, because whales are such voracious consumers. The other chapters, by Essington and Hunt, focus instead on how the abundance of prey

J. H. Geisler (*) Department of Geology and Geography and Museum, Georgia Southern University, Statesboro, GA 30460-8149, USA e-mail: [email protected]

(i.e., bottom-up) regulates whale abundance, indicating that the exploitation of whales had minimal ecological impacts. Subsequent chapters provide the data with which to evaluate both sides, but I found the quantitative, model-based study of Hunt to be the most compelling chapter in this section. The next section, Whales and Whaling, begins with a chapter by Lindberg and Pyenson on evolutionary patterns of Cetacea, with an emphasis on the fossil record. The authors’ main thesis, that cetaceans have evolved to take larger prey through time, is intriguing, although in my opinion far from established. They graphed diversity of cetacean taxa through time and figured a plot of mean body length by family. However, to really pull this together, they needed to directly figure the evolution of body size through time. Whereas some clades certainly show an increase (e.g., Mysticeti), it is unclear if other groups fit this pattern (e.g., Delphinoidea). Next, Reeves and Smith developed a classification of whaling based on operation (which replaces the term “fishery”) and era, which relates to the hunting technology employed. Their taxonomy seems useful; however, its real value will have to await its actual application by other researchers. Palumbi and Roman extended their provocative work on estimating pre-whaling populations using genetic diversity to humpback and fin whales. As in their previous studies, estimates are much higher than expected. Pfister and DeMaster

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estimated declines in whale biomass in the Bering Sea and Aleutian Islands, including variations in seasonal abundance. The data they generated will likely be useful for trophic models. Next, Danner et al. created a GIS to analyze the harvest and decline of mysticetes in the North Pacific. They stressed the importance of scale in such analyses; regional patterns can mask local declines. I consider this paper to be exemplary in its approach, although the application of its methods to other whaling regions will be limited by the paucity of data. In the next chapter, Forney and Wade presented a detailed summary of the abundance of killer whales in the world’s oceans. They found a positive correlation between killer whale abundance and latitude. Barrett-Lennard and Heise then reviewed the different types of killer whales, their population structures, and foraging behaviors. Even though there is little new data here, this chapter provides the background for understanding subsequent chapters. Reeves et al. have written a chapter summarizing anecdotal evidence, which is all there is, for the preying of killer whales on large cetaceans. They drew an interesting analogy with early inferences for the behaviors of North American carnivores, indicating that many ideas on killer whale feeding remain tentative. They also speculated that killer whales opportunistically fed on whales prior to whaling and that declines in pinnipeds may have led to increased predation on whales. This hypothesis certainly merits further investigation. The next eight chapters fall in the Process and Theory section. Williams discussed limits to body size and presented published, and some new, equations that relate organ size to body mass. Although physiological limits were just touched upon, there was more detailed discussion on how prey abundance may limit body size. One figure, which displays how long it would take, hypothetically, for killer whales to consume all prey of a single species, is striking and highlights the caloric needs of killer whales. Next, Croll et al. focused on the percentage of productivity consumed by whales in the North Pacific before and after whaling. The change was substantial, although uncertainties are large, which is an unavoidable problem that plagues several chapters in this section. Balance et al. examined evidence for the “Krill Surplus Hypothesis” in the Southern Ocean. Time series for species abundances in the Southern Ocean that they discuss are some of the best available, yet

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the difficulties in distinguishing cause and effect demonstrate the problems with studying whale ecology. In my opinion, the most insightful chapters in this section are by Doak et al. and Mangel and Wolf. Doak et al. tested the hypothesis that whaling caused killer whales to consume more Steller sea lions and otters. Their goal was to test the plausibility of the hypothesis by running their model with a wide range of possible values. This focus on what is possible, not what happened, seems appropriate given the uncertainties involved. Mangel and Wolf developed a model to determine the conditions where sequential prey collapse, instead of simultaneous collapse, would occur. This chapter contains a succinct yet excellent defense of modeling. It also includes specific predictions with which to test their model as well as future observations that may help to refine it. Springer et al. provided a summary of feeding, migration, and population change for whale species in response to exploitation. In another chapter, Branch and Williams investigated if killer whales “fished down” in the Southern Ocean in response to whaling. In addition, they examined if there was a correlation at the local/regional level between killer whale abundance and prey declines. Finally, Smith reviewed the ecology of whale falls on the sea floor. One of his insights really stands out; there should be a 40 year lag between the peak of whaling and its effects on the sulfophilic colonization of whale carcasses. If whaling has caused extinctions of whale-fall specialists, those extinctions may be occurring right now. The next five chapters are in the Case Studies section. Highsmith et al. developed a qualitative model to explain the locations of feeding areas for grey whales. While they did identify one important factor that determines feeding area location, the productivity of surface waters, the patchy distribution of grey whale feeding areas indicates that additional factors are involved. Clapham and Link examined three whale species, highlighting whaling history and possible ecological impacts. This chapter would have been more informative if different species/populations were chosen. For example, so little is known about grey whales of the North Atlantic that not much can be said about their former abundance or causes of their demise. Next, Whitehead expanded upon his previous work on sperm whales and focused on whether their populations are primarily controlled by

J Mammal Evol (2008) 15:227–229

bottom-up or top-down processes. In another chapter, Worm et al. looked for prey release effects in northern oceans in response to whaling. This is a solid study that found good evidence for prey release in the North Pacific. Finally, Costa et al. reviewed population trends of pinnipeds. Instead of implicating whaling, the authors primarily found that reproductive and foraging behaviors best explain which species rebounded after sealing abated. The Social Context section contains two chapters that discuss whaling from the human perspective. Bromley developed a qualitative model for resource exploitation. This is mainly a theoretical work, and it is unclear if it provides any direction for avoiding future cases of exploitation. In the next chapter, Orbach used the dichotomy of “preservation” versus “sustainable extraction” to categorize efforts to curtail whaling. As Orbach noted, conflicts among these two approaches will intensify as whale populations continue to rebound. This volume ends with two chapters in an Overview and Synthesis section. Kareiva et al., based in part on the preceding chapters, concluded that

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whaling had large effects on ocean ecosystems. Echoing statements by other contributors, they noted that the continued rebound of many whale species is the best way to assess their ecological importance, particularly if the rebound is spatially uneven. As is typical, the editors are the authors of the final chapter. There, in addition to summarizing the volume, they discussed the most promising areas of future research. Surprisingly, the editors disagree on what data are most needed to move forward, mirroring how far the scientific community is from reaching a consensus on the effects of whaling. This book did not convince me one way or the other as to the ecological impacts of whales, although I now have a better understanding of the challenges in studying their ecology. Regardless, I strongly recommend this book for anyone who is interested in this important, yet very difficult, problem. It represents a major step forward, making many unknowns known and giving hope that studies of the present-day ecology of whales will be more fruitful than ongoing and important efforts to reconstruct the recent, yet murky, past of whaling.