Ecology and Conservation of the Sirenia: Dugongs and Manatees by H. T. Marsh, T. J. O’Shea, and J. E. Reynolds III

When I 1st began seriously studying mammals, there were almost no books (as distinct from technical monographs in serials) devoted to sirenians, except for Colin Bertram’s (1963) In Search of Mermaids. Then came Hartman’s (1979) landmark American Society of Mammalogists publication, around the same time as several workshop proceedings on manatees and dugongs and a surge of other primary literature. That surge has continued uninterrupted to the present day, and now there are several substantial books in English, with various scopes, emphases, and levels of technical detail, including Reynolds and Odell (1991), Zeiller (1992), Powell (2002), and Reep and Bonde (2006), in addition to extensive sirenian information in Reynolds and Rommel (1999), Twiss and Reeves (1999), and other more general works. Several of these are useful as reference works for professional mammalogists, or as texts for undergraduate or graduate courses, or both. But all of them are eclipsed in these roles by the present volume. Helene Marsh, Tom O’Shea, and John Reynolds all stand in the 1st rank among the scores of workers who have contributed to our knowledge of the living sirenians during the past 35 years: Marsh as the longtime leader of dugong research in Australia and worldwide; O’Shea as a former leader of the United States government’s Sirenia Project in Gainesville, Florida; and Reynolds in several roles as a researcher on Florida manatees and other sirenians around the world, educator, chairman of the United States Marine Mammal Commission, and so on. Each is distinguished by the quantity and quality of his or her original research and conservation efforts regarding these endangered marine mammals. No one alive or dead would be better qualified to synthesize the present state of that knowledge—especially because they are jointly responsible for so much of it. We are fortunate to have from their hands this magisterial digest of what is known about the ecology and conservation of sirenians. If the answer to your question on these topics isn’t here, it probably isn’t in the primary literature either. In smoothly readable style and comprehensive detail, the authors take up in turn the evolutionary history and paleoecology of sirenians (including the extinct Steller’s sea cow [Hydrodamalis gigas] and the story of its discovery); the feeding biology of the living species; their behavior and habitat use; their life history, reproductive biology, and population dynamics; the threats to their survival; their conservation status; and conservation opportunities. About the only major aspects of the biology of sirenians not given detailed treatment are their morphology, physiology, pathology, parasitology, and genetics, and even these are touched on extensively in the text or in the copious online material that supplements 4 of the chapters. These latter appendixes include a summary of pertinent genomic investigations of the Afrotheria, tables of fossil taxa and their distribution, tables of food plants and animals reported eaten by the living species, comments on reproductive anatomy, a history of manatee population modeling, and a table of helminth parasites of sirenians. If anything important has been left out, I can’t think what it is. An example of a topic I describe as ‘‘not given detailed treatment’’ is the section on Infectious Diseases and Macroparasites in the Threats chapter. This runs for 8 pages, with the subheadings Die-offs due to disease, Viral diseases, Bacterial diseases, Mycotic (fungal) infections, Protozoal diseases, Macroparasites and commensals, Other pathological conditions, and Application of modern diagnostic tools for health assessments—plus the table of helminths in the online appendixes. The 3 and a half pages on viral and bacterial diseases break these down taxonomically, with references to the dozens of genera and species of pathogens reported in the literature. In other words, even here, there is enough detail for most practical purposes. This compilation is, at least for the time being, a more convenient and effective guide to this literature than can be found in the online bibliography of sirenians (Domning 2010), in which the reference capture and indexing is not complete for the literature of the past decade. This can be said for much of the book, which makes it ideal for anyone needing to get into the technical literature of the group quickly and with discrimination. Also noteworthy to this reviewer was the thoroughness and accuracy of the accounts of extinct sirenians in Chapters 2 and 3. Full disclosure: the authors have been very generous in describing my work in this area. But having so often seen neontologists seriously misinterpret statements that I and others have made about the fossils, I am impressed by writers who get all of it right. The book is well produced, with essentially no typographical errors apart from a column alignment problem in Table 8.7. There are numerous illustrations, including 4 pages of color photos (which, oddly, are color versions of black-and-white pictures printed elsewhere in the text), a good index, and a solid 68 pages of references including much recent gray literature. The references include just about all the sirenian literature to date that most readers will need. However, several of the small maps in Chapters 8 and 9 try to convey information with 3 or 4 different shades of gray. This is going a shade too far: if color printing was rationed, it could have been better used on these maps than in duplicative photos that mostly turn out to be rather monochromatic even in color.