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Marine ecology and fisheries
BOOK REVIEWS
Cushing, D. H., Marine Ecology and Fisheries, Cambridge University Press, 1975, 278 pp. Price: £9-00 (hardback--also available in paperback). Recent years have witnessed increasing concern over the problems of resource management. In the case of fisheries the political implications have made this a particularly sensitive issue highlighting the difficulties in reconciling commercial exploitation with long term conservation of fish stocks. Central to the issue is the deceptively simple question as to how much fishing is consistent with stable fish stocks. The brief answer is that we do not really know. In the volume under review the basic theme is that progress towards answering this and associated questions will only come about by taking a broad systems view in which the role of fisheries is set within the wider framework of marine ecology, it is currently fashionable to attempt the systems viewpoint and the techniques of computer simulation, control theory, ctc. have greatly extended the possibilities. The areas in which such work has proved valuable tend to be characterised by controlled environments in which cause and effect could be readily identified and where both the number of variables and the variances were somewhat constrained. The overwhelming impression is that this is not the representation of the overall level of knowledge reflecting the state of marine ecology. The book is divided into a dozen chapters, each of about twenty pages, together with a generous thirty-page bibliography and index. The major thrust of the first few chapters is directed towards exploring the basic mechanisms of production and the evolution of models founded upon key parameters. This is then tbllowed by a more detailed examination of the characteristics of fish populations and includes population dynamics, production cycles, etc. The concluding group of chapters concentrates on setting the role of fisheries back within the broader rubric of marine ecology and discusses some of the areas where cross fertilisation may be of benefit. In most chapters both a brief account of the historical background to the topic and a useful summary are provided which greatly assist the continuity between chapters. 75 Agricultural Systems (3) (1978)--~ Applied Science Publishers Lid, England, 1978 Printed in Great Britain
76
BOOK REVIEWS
The style, although compact, is very readable with a high information density. Some familiarity with basic mathematics is necessary but the vast majority of the analysis is confined to first order differential equations and variations upon the exponential theme, the most memorable exception being a fleeting reference to elliptical integrals. It would have been useful to have more detail regarding the problems of interpretation of multivariant data and statistical methods since sometimes authoritative lines appeared to be drawn through widely scattered data. Nevertheless, the book deserves a wide readership and should appeal to a range of interested parties. Inevitably many questions remain unanswered and the problems concerning the reliability and interpretation of data obtained from uncontrolled (uncontrollable!) experiments will exercise people for years to come. A. R. GLOYNE and C. J. SItEPIIERD
Ruthenberg, Hans, Farming Systems in the Tropics, Clarendon Press: O U P (Second edition), 1977. Price : Paper covers : £4.95. Hardback : £10.00. This second edition of Professor Ruthenberg's work is a welcome development of a very useful book. Originally based on lectures given to undergraduates, it is an extremely well-written and orderly account of tropical farming systems, especially useful to anyone preparing for applied work in the tropics. The author has based much of the book on his own experiences and the case studies are therefore drawn primarily from Africa and Asia, rather than from Latin America. The emphasis, for similar reasons, is on technical and economic interactions and farm-management data are treated in ways that allow analysis of smallholder f a r m i n g - - a difficult but essential task in the study of tropical farming systems. The second edition is some fifty pages longer than the original, part of this increase being in one of the two chapters contributed by J. D. MacArthur. Greater use has been made of systems theory as 'a mental guideline" and this is reflected in a longer introductory chapter. Some reorganisation of the material has taken place with a section on 'Fallow Systems" replacing the one on semi-permanent cultivation systems and 'Systems with Permanent Upland Cultivation' replacing the section on permanent cultivation on rain-fed land. The hypothesis underlying the book is that farmers are intentionally rational in organising their systems, given their objectives. This leads to three main assumptions: (a) that there are probably reasons for whatever is being done; (b) that change in the environment or economic context may, and probably will, produce discrepancies between what is currently done and the optimum farming system and (c) that farmers will change their systems if the change is 'satisfying" to them; that is, if they can see clearly the additional benefits to be derived and that these are not outweighed by other, less desirable, changes.
Cushing, D. H., Marine Ecology and Fisheries, Cambridge University Press, 1975, 278 pp. Price: £9-00 (hardback--also available in paperback). Recent years have witnessed increasing concern over the problems of resource management. In the case of fisheries the political implications have made this a particularly sensitive issue highlighting the difficulties in reconciling commercial exploitation with long term conservation of fish stocks. Central to the issue is the deceptively simple question as to how much fishing is consistent with stable fish stocks. The brief answer is that we do not really know. In the volume under review the basic theme is that progress towards answering this and associated questions will only come about by taking a broad systems view in which the role of fisheries is set within the wider framework of marine ecology, it is currently fashionable to attempt the systems viewpoint and the techniques of computer simulation, control theory, ctc. have greatly extended the possibilities. The areas in which such work has proved valuable tend to be characterised by controlled environments in which cause and effect could be readily identified and where both the number of variables and the variances were somewhat constrained. The overwhelming impression is that this is not the representation of the overall level of knowledge reflecting the state of marine ecology. The book is divided into a dozen chapters, each of about twenty pages, together with a generous thirty-page bibliography and index. The major thrust of the first few chapters is directed towards exploring the basic mechanisms of production and the evolution of models founded upon key parameters. This is then tbllowed by a more detailed examination of the characteristics of fish populations and includes population dynamics, production cycles, etc. The concluding group of chapters concentrates on setting the role of fisheries back within the broader rubric of marine ecology and discusses some of the areas where cross fertilisation may be of benefit. In most chapters both a brief account of the historical background to the topic and a useful summary are provided which greatly assist the continuity between chapters. 75 Agricultural Systems (3) (1978)--~ Applied Science Publishers Lid, England, 1978 Printed in Great Britain
76
BOOK REVIEWS
The style, although compact, is very readable with a high information density. Some familiarity with basic mathematics is necessary but the vast majority of the analysis is confined to first order differential equations and variations upon the exponential theme, the most memorable exception being a fleeting reference to elliptical integrals. It would have been useful to have more detail regarding the problems of interpretation of multivariant data and statistical methods since sometimes authoritative lines appeared to be drawn through widely scattered data. Nevertheless, the book deserves a wide readership and should appeal to a range of interested parties. Inevitably many questions remain unanswered and the problems concerning the reliability and interpretation of data obtained from uncontrolled (uncontrollable!) experiments will exercise people for years to come. A. R. GLOYNE and C. J. SItEPIIERD
Ruthenberg, Hans, Farming Systems in the Tropics, Clarendon Press: O U P (Second edition), 1977. Price : Paper covers : £4.95. Hardback : £10.00. This second edition of Professor Ruthenberg's work is a welcome development of a very useful book. Originally based on lectures given to undergraduates, it is an extremely well-written and orderly account of tropical farming systems, especially useful to anyone preparing for applied work in the tropics. The author has based much of the book on his own experiences and the case studies are therefore drawn primarily from Africa and Asia, rather than from Latin America. The emphasis, for similar reasons, is on technical and economic interactions and farm-management data are treated in ways that allow analysis of smallholder f a r m i n g - - a difficult but essential task in the study of tropical farming systems. The second edition is some fifty pages longer than the original, part of this increase being in one of the two chapters contributed by J. D. MacArthur. Greater use has been made of systems theory as 'a mental guideline" and this is reflected in a longer introductory chapter. Some reorganisation of the material has taken place with a section on 'Fallow Systems" replacing the one on semi-permanent cultivation systems and 'Systems with Permanent Upland Cultivation' replacing the section on permanent cultivation on rain-fed land. The hypothesis underlying the book is that farmers are intentionally rational in organising their systems, given their objectives. This leads to three main assumptions: (a) that there are probably reasons for whatever is being done; (b) that change in the environment or economic context may, and probably will, produce discrepancies between what is currently done and the optimum farming system and (c) that farmers will change their systems if the change is 'satisfying" to them; that is, if they can see clearly the additional benefits to be derived and that these are not outweighed by other, less desirable, changes.