Pacific Salmon Life Histories

Pacific salmon are an important biological and economic resource of countries of the North Pacific rim. They are also a unique group of fish possessing unusually complex life histories. There are seven species of Pacific salmon, five occurring on both the North American and Asian continents (sockeye, pink, chum, chinook, and coho) and two (masu and amago) only in Asia. The life cycle of the Pacific salmon begins in the autumn when the adult female deposits eggs that are fertilized in gravel beds in rivers or lakes. The young emerge from the gravel the following spring and will either migrate immediately to salt water or spend one or more years in a river or lake before migrating. Migrations in the ocean are extensive during the feeding and growing phase, covering thousands of kilometres. After one or more years the maturing adults find their way back to their home river, returning to their ancestral breeding grounds to spawn. They die after spawning and the eggs in the gravel signify a new cycle. Upon this theme Pacific salmon have developed many variations, both between as well as within species. Pacific Salmon Life Histories provides detailed descriptions of the different life phases through which each of the seven species passes. Each chapter is written by a scientist who has spent years studying and observing a particular species of salmon. Some of the topics covered are geographic distribution, transplants, freshwater life, ocean life, development, growth, feeding, diet, migration, and spawning behaviour. The text is richly supplemented by numerous maps, illustrations, colour plates, and tables and there is a detailed general index, as well as a useful geographical index.

The Behavior and Ecology of Pacific Salmon and Trout explains the patterns of mate choice, the competition for nest sites, and the fate of the salmon after their death. It describes the lives of offspring during the months they spend incubating in gravel, growing in fresh water, and migrating out to sea to mature. This thorough, up-to-date survey should be on the shelf of everyone with a professional or personal interest in Pacific salmon and trout. Written in a technically accurate but engaging style, it will appeal to a wide range of readers, including students, anglers, biologists, conservationists, legislators, and armchair naturalists.

"Fundamentally, the salmon's decline has been the consequence of a vision based on flawed assumptions and unchallenged myths.... We assumed we could control the biological productivity of salmon and 'improve' upon natural processes that we didn't even try to understand. We assumed we could have salmon without rivers." --from the introduction From a mountain top where an eagle carries a salmon carcass to feed its young to the distant oceanic waters of the California current and the Alaskan Gyre, salmon have penetrated the Northwest to an extent unmatched by any other animal. Since the turn of the twentieth century, the natural productivity of salmon in Oregon, Washington, California, and Idaho has declined by eighty percent. The decline of Pacific salmon to the brink of extinction is a clear sign of serious problems in the region. In Salmon Without Rivers, fisheries biologist Jim Lichatowich offers an eye-opening look at the roots and evolution of the salmon crisis in the Pacific Northwest. He describes the multitude of factors over the past century and a half that have led to the salmon's decline, and examines in depth the abject failure of restoration efforts that have focused almost exclusively on hatcheries to return salmon stocks to healthy levels without addressing the underlying causes of the decline. The book: describes the evolutionary history of the salmon along with the geologic history of the Pacific Northwest over the past 40 million years considers the indigenous cultures of the region, and the emergence of salmon-based economies that survived for thousands of years examines the rapid transformation of the region following the arrival of Europeans presents the history of efforts to protect and restore the salmon offers a critical assessment of why restoration efforts have failed Throughout, Lichatowich argues that the dominant worldview of our society -- a worldview that denies connections between humans and the natural world -- has created the conflict and controversy that characterize the recent history of salmon; unless that worldview is challenged and changed, there is little hope for recovery. Salmon Without Rivers exposes the myths that have guided recent human-salmon interactions. It clearly explains the difficult choices facing the citizens of the region, and provides unique insight into one of the most tragic chapters in our nation's environmental history.

Every year, countless juvenile Pacific salmon leave streams and rivers on their migration to feeding grounds in the North Pacific Ocean and the Bering Sea. After periods ranging from a few months to several years, adult salmon enter rivers along the coasts of Asia and North America to spawn and complete their life cycle. Within this general outline, various life history patterns, both among and within species, involve diverse ways of exploiting freshwater, estuarine, and marine habitats. There are seven species of Pacific salmon. Five (coho, chinook chum, pink, and sockeye) occur in both North America and Asia. Their complex life histories and spectacular migrations have long fascinated biologists and amateurs alike. Physiological Ecology of Pacific Salmon provides comprehensive reviews by leading researchers of the physiological adaptations that allow Pacific Salmon to sustain themselves in the diverse environments in which they live. It begins with an analysis of energy expenditure and continues with reviews of locomotion, growth, feeding, and nutrition. Subsequent chapters deal with osmotic adjustments enabling the passage between fresh and salt water, nitrogen excretion and regulation of acid-base balance, circulation and gas transfer, and finally, responses to stress. This thorough and authoritative volume will be a valuable reference for students and researchers of biology and fisheries science as they seek to understand the environmental requirements for the perpetuation of these unique and valuable species.

This work gives a critical overview on the evolution and population biology of salmon and their relatives. It should appeal to investigators in each of the scientific disciplines it integrates - evolutionary biology, ecology, salmonid biology, management and conservation. Variation in salmonids can be used to illustrate virtually all evolution.

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.

Destruction of habitat is the major cause for loss of biodiversity including variation in life history and habitat ecology. Each species and population adapts to its environment, adaptations visible in morphology, ecology, behaviour, physiology and genetics. Here, the authors present the population ecology of Atlantic salmon and brown trout and how it is influenced by the environment in terms of growth, migration, spawning and recruitment. Salmonids appeared as freshwater fish some 50 million years ago. Atlantic salmon and brown trout evolved in the Atlantic basin, Atlantic salmon in North America and Europe, brown trout in Europe, Northern Africa and Western Asia. The species live in small streams as well as large rivers, lakes, estuaries, coastal seas and oceans, with brown trout better adapted to small streams and less well adapted to feeding in the ocean than Atlantic salmon. Smolt and adult sizes and longevity are constrained by habitat conditions of populations spawning in small streams. Feeding, wintering and spawning opportunities influence migratory versus resident lifestyles, while the growth rate influences egg size and number, age at maturity, reproductive success and longevity. Further, early experiences influence later performance. For instance, juvenile behaviour influences adult homing, competition for spawning habitat, partner finding and predator avoidance. The abundance of wild Atlantic salmon populations has declined in recent years; climate change and escaped farmed salmon are major threats. The climate influences through changes in temperature and flow, while escaped farmed salmon do so through ecological competition, interbreeding and the spreading of contagious diseases. The authors pinpoint essential problems and offer suggestions as to how they can be reduced. In this context, population enhancement, habitat restoration and management are also discussed. The text closes with a presentation of what the authors view as major scientific challenges in ecological research on these species.