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Dynamics and exploitation of unstable percid populations
284
water quality standards to protect fish in fresh water. They explain how not all such attempts, including some very recent ones, are firmly based on a quantitative understanding of the real effects of pollutants on fish communities. The book ends with a short treatment of the economic issues to be faced in protecting fisheries from pollution and a perceptive set of general conclusions. The reviewer's general conclusion is that Pollution and Freshwater Fish is the best concise introduction to this complex subject currently in print. R.G.J. SHELTON
Scottish Office Agriculture and Fisheries Department Fresh water Fisheries Laboratory
Faskallv Pitlochry PH16 5LB UK
DYNAMICS AND EXPLOITATION OF UNSTABLE PERCID POPULATIONS
Dynamics and Exploitation of Unstable Percid Populations, A.D. Buijse, University of Wageningen, Wageningen, 1992, 167 pp., ISBN 90-5485-001-9. This softback book is a PhD thesis, and in the style of many universities in continental Europe and the United States of America, consists of a series of chapters written in the form of scientific papers, preceded by a general introduction to the thesis. Several of the chapters of this thesis have been accepted for publication in refereed journals. The thesis considers the percid fishery of Lake IJssel in the Netherlands. Lake IJssel is a large (182 000 ha), shallow, eutrophic lake which was formerly an inland sea. European eel (Anguilla anguilla), Eurasian perch (Perca fluviatilis) and pikeperch (Stizostedion lucioperca) are the fish species which are heavily commercially exploited. The percids are exploited by gill netting and yields are characterized by high interannual variation, caused by changes in year-class strength. Buijse's thesis seeks to identify the causes of year-class strength variability and examines management measures for yield optimization. Following the introduction, specific chapters deal with: the influence of water clarity on the catchability of resident species in bottom trawls; yearclass strength of perch and pikeperch in relation to stock size, water temperature and wind; piscivory, growth and size-selective mortality of age 0 pikeperch; flexibility in the onset of piscivory and growth depensation in perch; evaluation of management strategies in the gill net fishery by size and age
285
structured modelling; and recruitment-induced uncertainty in yield and the consequences for management of percid gill net fisheries. Much of the value of the thesis lies in its utilization and careful analysis of information from a large data set extending back to 1966. This has been supplemented with more recent studies targeted to provide key information on aspects of recruitment control such as Chapter 5, "Flexibility in the onset of piscivory and growth depensation in Eurasian perch, Percafluviatilis L." Although this thesis is unlikely to receive a wide readership by virtue of its specialized subject, it is likely to be a very useful text for fisheries biologists working in systems where percids are important. In particular, much of the information may be of direct relevance to fisheries in North America where there are important sport and commercial fisheries for closely related species such as yellow perch (Percaflavescens), walleye (Stizostedion vitreum) and sauger (Stizostedion canadense). MARTYN C. LUCAS
Department of Biological Sciences University of Durham South Road Durham DH1 3LE UK
water quality standards to protect fish in fresh water. They explain how not all such attempts, including some very recent ones, are firmly based on a quantitative understanding of the real effects of pollutants on fish communities. The book ends with a short treatment of the economic issues to be faced in protecting fisheries from pollution and a perceptive set of general conclusions. The reviewer's general conclusion is that Pollution and Freshwater Fish is the best concise introduction to this complex subject currently in print. R.G.J. SHELTON
Scottish Office Agriculture and Fisheries Department Fresh water Fisheries Laboratory
Faskallv Pitlochry PH16 5LB UK
DYNAMICS AND EXPLOITATION OF UNSTABLE PERCID POPULATIONS
Dynamics and Exploitation of Unstable Percid Populations, A.D. Buijse, University of Wageningen, Wageningen, 1992, 167 pp., ISBN 90-5485-001-9. This softback book is a PhD thesis, and in the style of many universities in continental Europe and the United States of America, consists of a series of chapters written in the form of scientific papers, preceded by a general introduction to the thesis. Several of the chapters of this thesis have been accepted for publication in refereed journals. The thesis considers the percid fishery of Lake IJssel in the Netherlands. Lake IJssel is a large (182 000 ha), shallow, eutrophic lake which was formerly an inland sea. European eel (Anguilla anguilla), Eurasian perch (Perca fluviatilis) and pikeperch (Stizostedion lucioperca) are the fish species which are heavily commercially exploited. The percids are exploited by gill netting and yields are characterized by high interannual variation, caused by changes in year-class strength. Buijse's thesis seeks to identify the causes of year-class strength variability and examines management measures for yield optimization. Following the introduction, specific chapters deal with: the influence of water clarity on the catchability of resident species in bottom trawls; yearclass strength of perch and pikeperch in relation to stock size, water temperature and wind; piscivory, growth and size-selective mortality of age 0 pikeperch; flexibility in the onset of piscivory and growth depensation in perch; evaluation of management strategies in the gill net fishery by size and age
285
structured modelling; and recruitment-induced uncertainty in yield and the consequences for management of percid gill net fisheries. Much of the value of the thesis lies in its utilization and careful analysis of information from a large data set extending back to 1966. This has been supplemented with more recent studies targeted to provide key information on aspects of recruitment control such as Chapter 5, "Flexibility in the onset of piscivory and growth depensation in Eurasian perch, Percafluviatilis L." Although this thesis is unlikely to receive a wide readership by virtue of its specialized subject, it is likely to be a very useful text for fisheries biologists working in systems where percids are important. In particular, much of the information may be of direct relevance to fisheries in North America where there are important sport and commercial fisheries for closely related species such as yellow perch (Percaflavescens), walleye (Stizostedion vitreum) and sauger (Stizostedion canadense). MARTYN C. LUCAS
Department of Biological Sciences University of Durham South Road Durham DH1 3LE UK