The success of the previous volumes in this series attests to the buoyancy of the current expansion of the aquaculture industry, and the importance which it is beginning to achieve in the rural economies of many developed countries as well as those less favoured. In the last volume, emphasis was given to certain specialist areas which had become more important as the industry had acquired a more sophisti cated scientific base. This emphasis is continued, but in each of the chapters of the present volume there are, we believe, many data of general significance to the farmer and the project manager as well as to the pro fessional aquaculture scientist. David Alderman, of the English Ministry of Agriculture, Fisheries and Food Laboratories, at Weymouth, Dorset, provides a very detailed and deeply researched review of therapy of fish diseases. This subject is import ant in environmental and human health terms as well as in relation to the fish themselves, and is an area where all farmers, and their professional veterinary advisers, require considerable knowledge if they are to ensure the reputation of the industry and its produce."

with the issues involved in the management of salmon fishing. farming and ranching and the implications for production costs and the availa bility of supplies. Chapters 6 and 7 investigate processing. marketing and distribution and Chapter 8 discusses the workings of salmon markets and the main factors affecting the demand for salmon. Finally. chapter 9 summarises the main findings of the study and considers the issues likely to define the future of the industry. The main interest of the book is in salmon sold commer cially and mention is only made in passing of the rather different. though important. issues involved in the management of sport or recreation fisheries. This book does not cover all species of salmon but concentrates on the main species of current commercial significance. These are the five commercially important species of Pacific salmon all of which belong to the single separate genus ONCORHYNCHUS together with SALMO SALAR. the Atlantic salmon. The related SALMO GAIRDNERI (rainbow trout) and SALMO TRUTTA (brown troutl seatrout) are outside the scope of the book. although since these compete closely with salmon. the relationship is discussed. 1.2 THE SALMON: LIFE CYCLE AND SPECIES The family salmonidae is indigenous to the Northern Hemisphere and is found from the temperate zone northwards to beyond the Arctic Circle. 1n both Pacific and Atlantic waters. They are not. native to the Southern Hemisphere but have been successfully introduced into New Zealand. into Argentina. Venezuela and more recently Chile and the Kerguelen Islands."