Tropical Estuarine Fishes

Journal of Fish Biology (2003) 62, 982–985 doi:10.1046/j.1095-8649.2003.00079.x, available online at http://www.blackwell-synergy.com

BOOK REVIEWS INSHORE FISHERIES MANAGEMENT. Edited by D. Symes & J. Phillipson. xviii 318 pp. Published by Kluwer Academic Publishers, Dordrecht (Reviews: Methods and Techniques in Fish Biology and Fisheries, 2), 2001. Price £62
00. ISBN 1-4020-0128-2.

Surprisingly, for a book in the Methods and Techniques in Fish Biology and Fisheries series, this volume contains almost no information on the biological basis for management of fisheries. Rather, it concerns the socioeconomic infrastructure of fisheries which occupy the niche between freshwater and offshore marine fisheries and the institutions set up for their management. This is well covered in eight chapters that provide somewhat disparate views of national fisheries in north-west Europe, varying from a clear-cut description of the relevant fisheries in The Netherlands to an account of the regulatory framework of the U.K. inshore fishery, and which strive to define an ‘inshore’ fishery but without arriving at a consensus. These are followed by four chapters on the social organization theme, four more on management issues – chiefly conflicts and integration – and, finally, by the editors’ views of what the future holds. Although the whole gamut of problems assailing these fisheries is exposed within the book, and management objectives are mentioned from time to time, I found no discussion of what these objectives might be and therefore was left rather unsatisfied with what I had learnt. Management must have a goal, and the goal has to be described in such a way that we can see how to approach it, and know when it is achieved. Maybe, as one actively involved in the scientific end of fisheries management, I was expecting too much. There is frequent repetition of some aspects of inshore fisheries and a number of omissions which might otherwise have helped explain a little more about the real policy issues of managing small-boat, polyvalent and mixed species (seasonal) fisheries. For example, the implementation of the 1986 Salmon Act in the U.K. led to the prohibition of the use of fixed engines (gillnets, trammel nets, tangle nets and traps) within the 6 mile coastal zone of England and Wales. Thus, freshwater legislation, aimed at protecting migrating salmon in coastal waters, would, in theory, curtail a considerable legitimate marine fishery. The Act eventually included a clause enabling sea fisheries committees to set up bye-laws authorizing fixed engines in specified areas (essentially, where they would do least harm to salmon or sea trout), but a blind eye had to be turned to for several years whilst these bye laws were put in place. I am also particularly surprised to see no reference to the ban, in 1990, on commercial fishing for sea bass in Irish waters, pursuant to a policy to reserve this highly valued but dwindling resource for sport anglers, and thus promote tourism. Interestingly, this contrasts with the observation that neither Ireland nor the U.K. has been able to preserve salmon for recreational use, when the economic argument for doing so is unassailable. Nevertheless, this is a valuable book for fisheries biologists – and anyone interested in management of the coastal zone – since it lucidly describes the character of inshore fisheries in northern Europe, their role in the fabric of coastal communities and the means by which they are regulated both through legislation and at the community level. It is written without recourse to jargon and, though the authors may have limited their contributions to regions and topics close to their personal experience, it provides an insight into those management issues that do not concern mere biological sustainability. The book does not, however, live up to the Series Editor’s goal of providing ‘a forum for discussion on the living systems and the organisms inhabiting them’ (unless Homo sapiens is the target species), and it is difficult to perceive a ‘new application of science and technology’. MIKE PAWSON CEFAS, Lowestoft

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doi:10.1046/j.1095-8649.2003.00080.x, available online at http://www.blackwell-synergy.com TROPICAL ESTUARINE FISHES: ECOLOGY, EXPLOITATION AND CONSERVATION. By S. J. M. Blaber. xii 372 pp. Published by Blackwell Science, Oxford (Fish and Aquatic Resources Series, 7), 2000. Price £79
50. ISBN 0-632-05655-X.

This book is lavishly illustrated with case studies, data and figures from tropical areas worldwide, and hence there is much of general value for fish biologists. Where necessary, the author directs readers to general fish texts in order for them to then tackle the precise aspects of the tropics, indicating where knowledge is poor and giving directions for further study and understanding, such as the reproduction of certain species. As Steve Blaber is able to call on a wealth of his own work as well as that of collaborators worldwide, this reviewer believes that there is no better tropical fish biologist to produce such an informative and readable volume. On a personal note, even those of us working in temperate estuaries will find many features for comparison with our systems. The first two chapters give the scope, definitions and an introduction to the concepts tackled later. Examples are given of the different types of tropical estuaries, so that the volume is also of value for the general estuarine ecologist. The consideration of both normal and catastrophic features in estuarine areas indicates the main environmental characteristics and stressors affecting the fishes. The author also provides an excellent demonstration of why the tropics are important for fishes and the biology of those fishes able to tolerate such conditions. Chapter 3 develops ideas regarding the structure of fish communities, and there is sufficient information here both for the specialist and the newcomer to the field. In this, the text is valuable for all estuarine scientists in discussing why salinity is not the only important feature in these environments – an aspect often overlooked. There are details of the different types of fishes (as guilds or ecological subdivisions) present such as resident species, marine migrants, etc., and a large amount of precise information regarding taxonomic, abundance and biomass-related community structure. The review adds to the present discussion about estuarine definitions by describing estuarine coastal zones and indicating that the term ‘marine’ is a misnomer for certain areas given that many fish do not occur outside the estuarine zone. The trophic structure and ecology of the areas are discussed (Chapter 4), including diet and morphological adaptation and specializations observed, ontogenetic shifts and feeding types both by the method used and by the food taken. The food webs illustrate the high species diversity coupled with a complexity of trophic structure. Of particular interest and importance for all interested in the functioning of systems are the effects of natural and anthropogenic perturbations on trophic structure. Similarly, reproductive aspects are treated in detail (Chapter 5) and cover different spawning strategies, behaviour and stimuli related to tropical features such as large-scale river flow changes both internal to the estuary and external to the estuary, such as tidal phases. The knowledge of the precise ecology of larval fish is important in order to consider recruitment strategies and transport patterns. Again, there are many examples even to the extent of discussing the transport of larvae with mangrove leaves! The structure and hydrology of the estuarine areas (Chapter 6) illustrate the greater extremes present in tropical estuaries in comparison to temperate ones. The text is valuable in bringing together necessary experimental information, such as on salinity and turbidity preferences, to complement and help the interpretation of field surveys. This chapter shows the importance of understanding the physics of an area before being able to understand the biological features, but there is also a good description of vegetation as a community structuring force. Chapter 7 adds to the debate regarding the terms ‘estuarine dependence’ and ‘estuarine opportunists’, and the author, like several others, has difficulty finding examples for the former. In this, the discussion shows both the development of estuarine fish faunas and the advantages and disadvantages for the fish inhabiting these areas. The uses of, threats to and anthropogenic impacts on estuarine fishes are covered in Chapters 8–10. The section on estuarine fisheries gives many comparative data for yields

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and shows the large variation in different systems. There is also a valuable description of gear and the effects of fishing (at subsistence, artisanal, commercial and recreational levels) leading to the management of fisheries. This touches on the environmental, socioeconomic, technological, legal and administrative aspects and thus leads to a discussion of integrated management. The effects of fishing focuses, rightly, on the by-catch of non-target sizes and species, even up to mammals, and thus the knock-on effects for trophic functioning. The influence of anthropogenic activities is as great in these areas as elsewhere, and hence there are welcome case studies on the effects of infrastructure, dredging, habitat loss, agriculture, etc., as well as on the synergistic effects of unnatural levels of natural stressors (oxygen, salinity and temperature). As with the current concerns for these areas, the author rightly emphasizes the relative importance of changes to the hydrology of systems, the changes to and loss of habitat, and the introduction of materials (oils, metals, etc.). As with many aquatic systems, while pollution often gets a greater public attention, the loss of habitat is of greater concern (and is perhaps irreversible). The book concludes with sections on conservation, rehabilitation (restoration) and climate change (Chapter 11) by indicating the need for the sustainable management of the available resources (both the fishes and their habitat features). This is needed in order to protect the fishes and their fisheries. The final plea, for the management of external influences as well as of internal ones, is well made and well accepted. There are some very minor (and personal) quibbles with the book – that the information of bird predators and mangroves seemed out of place, that the section on estuarine characteristics could have come earlier in order to tell the reader about the underlying features, and that the section on climate change could be separated and given even greater prominence. In addition, a short concluding section bringing the main messages together would have been welcome. Despite this, the book is an excellent addition to the literature that will be valuable at all levels both in teaching and research. Finally, the inclusion of almost 1000 references makes it an indispensable reference work. MIKE ELLIOTT Institute of Estuarine & Coastal Studies, University of Hull

doi:10.1046/j.1095-8649.2003.00081.x, available online at http://www.blackwell-synergy.com TROUT AND SALMON: ECOLOGY, CONSERVATION AND REHABILITATION. By D. T. Crisp. xi 212 pp. Published by Fishing News Books, Oxford, 2000. Price £35. ISBN 0-85238-256-1.

This paperback book deals primarily with the aspects of the biology and management of Atlantic salmon Salmo salar and brown trout Salmo trutta, with a focus on the U.K. The high economic value of these species is reflected in the relatively large amount of information available. For a single author to cover ecology, conservation and rehabilitation in a volume of less than a couple of hundred pages of text (excluding appendices, index and glossary) is a tall order. Therefore, it is not surprising that the book does not provide a thorough review of many of the topics considered. It should not be used as a substitute for searching the literature. On the other hand, some areas are covered extensively and useful introductions are provided to a wide range of topics. The book is well referenced and clearly illustrated with the exception of the photographs, which have not reproduced well. Distinctions between established scientific fact and the author’s opinions about management of trout and salmon are generally made clearly. The book covers predominantly the freshwater life stages and devotes less than two pages to ‘sea life’. With the exception of a part of the first chapter, which includes data on the economic values of salmonid fishes, the first part of the book deals with biology. Chapters include taxonomy, distribution and importance, the life cycles and general biology (including subsections on ‘behaviour and social interaction’, population density, and survival and growth), water quantity and quality and also quality of the gravel, and environmental requirements and limitations. I can think of no other book that provides a similar

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balance in these topics between accessibility to a wide readership and detailed reference to key data. However, the limited extent of coverage is illustrated clearly by comparison with a recent compilation of reviews of some aspects of the ecology of Atlantic salmon (Can. J. Fish. Aquat. Sci. 55 (Suppl. 1), 1998). The hub of the book, on habitat requirements, would benefit substantially from a more in-depth consideration of basic ecological principles, such as the application of ideal free and ideal despotic distributions and their implications for defining preferred habitats. The book moves on to consider aspects of management. In Chapter 5, on human influence, there are sections on civil engineering, fishing and fisheries management, industry, transport and roads, urban development, forestry and agriculture. Following this section on degradation, Chapter 6 searches for the antidotes and deals with the assessment, conservation, improvement and rehabilitation of salmonid habitat. These chapters, which will be of great interest to many fisheries practitioners, are generally well thought out and clearly argued with reference, where possible, to supporting literature. This exemplifies a great strength of the book: the reinforcement of the principle of applying sound scientific information to practical management. The final chapter comprises a series of the author’s opinions regarding priorities in future research. I would have liked to have seen more detail and explanation of how he sees long-term population studies being developed. Similarly, it would be interesting to have a more explicit account of the author’s views of exactly which deficiencies and contradictions in our understanding of habitat requirements might be addressed by increased understandings of which aspects of behaviour and physiology. These are not meant as serious criticisms but rather an acknowledgement that the author has much of interest and importance to say. This is illustrated nowhere more clearly than in the final section of the chapter, which is a hard-hitting plea for improved monitoring, documentation and accountability. I hope that the text will stimulate debate about how the scientific and management communities can deliver improvements in reporting the results of management actions in primary literature. I would be surprised if there are workers studying the ecology, conservation or rehabilitation of salmon and trout who would not benefit significantly from reading this book, if only for comparison with their own views. More important, perhaps, the book summarizes much of our knowledge of what salmon and trout are and how they interact with their environment. This result is achieved in a text that will be accessible to a wide range of the people who have a part to play in the management of fisheries and fish populations, not least because the practical applications of the understanding of the biology are well documented. The author has produced a useful addition to the literature concerning salmon and trout. J. D. ARMSTRONG Fisheries Research Services Freshwater Laboratory, Pitlochry

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2003 The Fisheries Society of the British Isles, Journal of Fish Biology 2003, 62, 982–985