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Genetic conservation of salmonid fishes
Book reviews /Fisheries Research 22 (1995) 319-324
323
Genetic conservation of salmonid fishes
Genetic Conservation of Salmonid Fishes, J.G. Cloud and G.H. Thorgaard tors), Plenum Press, New York and London, 8.
(Edi1993, $89.50, ISBN 0-306-44532-
This book is Volume 248 in the NATO series of Advanced Science Institutes. It presents the proceedings of a meeting held in 1991 in Idaho and Washington states. There are 27 chapters, differing in length and in content, ranging from short technical papers to more broadly based reviews. The first 15 chapters deal with broad principles and applications such as stock definitions, management goals, theoretical hatchery effects, potential impacts of transgenic fish, germplasm repositories and cryopreservation. Six of the later chapters address particular species or localities, such as sea-run cutthroat trout in the United States and Atlantic salmon in Spain. The authors are all well-known and well-regarded in their fields. The book contains something for everyone with an interest in genetic conservation of salmonids and as such it is something of a curate’s egg. Overall, the editing is uneven. Typographical errors are irritatingly common, some figures have incorrect legends and some sentences even lack a verb! Nevertheless, it is a useful source of information and references on relevant topics and techniques, drawing, as it does, on many examples of different salmonid stocks and species and even on the experiences gained in plant and wild life conservation. Sensitivity to the need for care and prudence in the management of fish stocks, particularly in ensuring that the interaction of cultivated and wild stocks is not negative, is, if anything, even more relevant today than it was in 199 1. Why, then, does this topical book leave me vaguely unsatisfied? While many of the authors admit that our understanding of the adaptations of wild salmonids to habitat and environmental factors is inadequate, the predominant overall approach of this book is that almost any genetic alteration made by man is inevitably, and virtually irreversibly, bad. This may or may not be true; personally I doubt that it is. Riddell, for example, stresses that each localised spawning population of a species is different and ought to be conserved. He goes even further (p. 33), “It is simply untenable to expect managers to prove value in each localised population before it will be conserved”. Gausen (p. 18 1) states that “crossbreeding between farmed and wild salmon in nature is expected to lead to the loss of genetically determined characteristics and adaptive traits in local wild populations” Levings, too, takes a similar view ( p. 49)) “If the original genetic structure is no longer present, if environments vary outside the natural range, or if restored habitats are different to those originally present, restoration of salmonid populations may be difficult”. Gall (p. 90) puts another view neatly, “there will always be some genetic change resulting from artificial production that is different than (sic) changes expected in the natural environment, but the changes can be managed... (N)atural populations do not exist in a static genetic condition”. Wohlfarth (p. 228) tabulates
324
Book reviews /Fisheries Research 22 (1995) 319-324
some concrete instances where domestic x wild crosses performed better in natural waters (italics added) than did pure wild or pure domestic stock. Cuanco et al. (p. 269ff) usefully review the use of supplementation as an aid to natural stock (italics added) restoration. Clark’s pithy comment (p. 133) ought to give us particular pause for thought, “almost all present day U.S. crops are based on introduced plant germplasm”. Surely we have here the thesis - antithesis of a meaningful dialectic? This is what the book appears to lack: it espouses all too cosily (but with some notable exceptions) the view that all stocks ought to be conserved. This errs on the side of caution, perhaps even of prudence. But one might have expected that, by now, salmonids would have provided a number of robust models for the study of local genetic adaptedness, with concrete examples of the fitness and inheritance of different genotypes in different environments. In point of fact, we can still rarely distinguish between selective and stochastic factors in determining genetic differences between stocks. Without this knowledge we may be left, uneasily, with teleological explanations such as Behnke’s (p. 43), “Intraspecific fracturing of a species into numerous discrete stocks or populations is driven by natural selection to expand future options for genetic continuity ...“. There is, as I said, something here for everyone. Much of it has been well treated elsewhere, but the range of topics and technique brought together in this volume makes it a very useful compendium, and one that will stimulate thought and debate. To mimic Michelin, “Worth a read”, but not cheap. N.P. WILKINS Department ofZoology National Universityof Ireland UniversityCollege Galway Ireland
323
Genetic conservation of salmonid fishes
Genetic Conservation of Salmonid Fishes, J.G. Cloud and G.H. Thorgaard tors), Plenum Press, New York and London, 8.
(Edi1993, $89.50, ISBN 0-306-44532-
This book is Volume 248 in the NATO series of Advanced Science Institutes. It presents the proceedings of a meeting held in 1991 in Idaho and Washington states. There are 27 chapters, differing in length and in content, ranging from short technical papers to more broadly based reviews. The first 15 chapters deal with broad principles and applications such as stock definitions, management goals, theoretical hatchery effects, potential impacts of transgenic fish, germplasm repositories and cryopreservation. Six of the later chapters address particular species or localities, such as sea-run cutthroat trout in the United States and Atlantic salmon in Spain. The authors are all well-known and well-regarded in their fields. The book contains something for everyone with an interest in genetic conservation of salmonids and as such it is something of a curate’s egg. Overall, the editing is uneven. Typographical errors are irritatingly common, some figures have incorrect legends and some sentences even lack a verb! Nevertheless, it is a useful source of information and references on relevant topics and techniques, drawing, as it does, on many examples of different salmonid stocks and species and even on the experiences gained in plant and wild life conservation. Sensitivity to the need for care and prudence in the management of fish stocks, particularly in ensuring that the interaction of cultivated and wild stocks is not negative, is, if anything, even more relevant today than it was in 199 1. Why, then, does this topical book leave me vaguely unsatisfied? While many of the authors admit that our understanding of the adaptations of wild salmonids to habitat and environmental factors is inadequate, the predominant overall approach of this book is that almost any genetic alteration made by man is inevitably, and virtually irreversibly, bad. This may or may not be true; personally I doubt that it is. Riddell, for example, stresses that each localised spawning population of a species is different and ought to be conserved. He goes even further (p. 33), “It is simply untenable to expect managers to prove value in each localised population before it will be conserved”. Gausen (p. 18 1) states that “crossbreeding between farmed and wild salmon in nature is expected to lead to the loss of genetically determined characteristics and adaptive traits in local wild populations” Levings, too, takes a similar view ( p. 49)) “If the original genetic structure is no longer present, if environments vary outside the natural range, or if restored habitats are different to those originally present, restoration of salmonid populations may be difficult”. Gall (p. 90) puts another view neatly, “there will always be some genetic change resulting from artificial production that is different than (sic) changes expected in the natural environment, but the changes can be managed... (N)atural populations do not exist in a static genetic condition”. Wohlfarth (p. 228) tabulates
324
Book reviews /Fisheries Research 22 (1995) 319-324
some concrete instances where domestic x wild crosses performed better in natural waters (italics added) than did pure wild or pure domestic stock. Cuanco et al. (p. 269ff) usefully review the use of supplementation as an aid to natural stock (italics added) restoration. Clark’s pithy comment (p. 133) ought to give us particular pause for thought, “almost all present day U.S. crops are based on introduced plant germplasm”. Surely we have here the thesis - antithesis of a meaningful dialectic? This is what the book appears to lack: it espouses all too cosily (but with some notable exceptions) the view that all stocks ought to be conserved. This errs on the side of caution, perhaps even of prudence. But one might have expected that, by now, salmonids would have provided a number of robust models for the study of local genetic adaptedness, with concrete examples of the fitness and inheritance of different genotypes in different environments. In point of fact, we can still rarely distinguish between selective and stochastic factors in determining genetic differences between stocks. Without this knowledge we may be left, uneasily, with teleological explanations such as Behnke’s (p. 43), “Intraspecific fracturing of a species into numerous discrete stocks or populations is driven by natural selection to expand future options for genetic continuity ...“. There is, as I said, something here for everyone. Much of it has been well treated elsewhere, but the range of topics and technique brought together in this volume makes it a very useful compendium, and one that will stimulate thought and debate. To mimic Michelin, “Worth a read”, but not cheap. N.P. WILKINS Department ofZoology National Universityof Ireland UniversityCollege Galway Ireland