The last major synthesis of our knowledge of fish migration and the underlying transport and guidance phenomena, both physical and biological, was "Fish Migration" published 16 years ago by F.R. Harden Jones (1968). That synthesis was based largely upon what could be gleaned by classical fishery-biology techni.ques, such as tagging and recapture studies, commercial fishing statistics, and netting and trapping studies. Despite the fact that Harden Jones also provided, with a good deal of thought and speculation, a theoretical basis for studying the various aspects of fish migration and migratory orientation, progress in this field has been, with a few excepti.ons, piecemeal and more disjointed than might have been expected. Thus we welcomed the approach from the NATO Marine Sciences Programme Panel and the encouragement from F.R. Harden Jones to develop a proprosal for, and ultimately to organize, a NATO Advanced Research Institute (ARI) on mechanisms of fish migration. Substantial progress had been made with descriptive, analytical and predictive approaches to fish migration since the appearance of "Fish ~ligration." Both because of the progress and the often conflicting results of research, we felt that the time was again right and the effort justified to synthesize and to critically assess our knowledge. Our ultimate aim was to identify the gains and shortcomings and to develop testable hypotheses for the next decade or two.

Fish migration is important and spectacular. Migratory fish gather energy in one portion of the environment and transport it to other areas, where it often becomes available to humans or to other elements in the ecosystem. Migration brings fish into situations that allow easy harvest as they concentrate along migration routes. Their journeys also make them vulnerable to human intereference at critical points along their route. Salmon, for example, may harvest plankton in the open ocean and transport that food energy to coastal and inland regions, where it is captured by fisheries or deposited in inland streams and utilized by the flora and fauna of the region. These salmon are able to complete journeys of thousands of kilometers from their natal streams to oceanic feeding grounds and back to the same home streams, an accomplishment that strains our credi bili ty . We now understand some of the timing and guiding stimuli used in these migrations, and mechanisms can be logically proposed, on the basis of the established abilities of fishes, to account for the unexplained portions of the migrations. There is no single factor guiding these fish. Instead, they are dependent on the presence in their environment of a great variety of appropriate orienting and timing stimuli. These stimuli are vulnerable to human interference. The more widespread and easily available the information on these requirements, the more readily fish can be protected from such interference.

Since the publication of The Migrations of Fish by Prof. Alexander Meek in 1916, a number of books have been published on this subject. However, most of these books only cover one type of migratory mechanisms. This book aims to overcome this drawback by presenting a comprehensive coverage of all life history strategies-potadromy, anadromy, catadrom

Migration - a problem of definition; Patterns of migration; Orientation; Bioenergetics; Physiology; Ecology and evolution.

Among the roughly 30,000 species of fish, migratory species account for only 165 species, but most of them are very important fisheries resources. This book presents up-to-date innovative research results on the physiology and ecology of fish migration. It focuses on salmon, eels, lampreys, and bluefin tuna. The book examines migratory behavior, sp