Jim Lichatowich has been a fisheries scientist for twenty-nine years, working for most of that time in salmon management and research in Oregon and Washington. He is a member of three independent teams of scientists investigating the salmon crisis, and has written numerous scientific and technical papers on the history, current status, and future prospects of salmon. His essays have appeared in a variety of publications including Trout magazine, Peninsula magazine, Riverkeeper, and Shirkin Comment

.

Hooknose

Before the Endangered Species Act; before shopping centers covered streams with asphalt; before dams and dynamos harnessed the energy of wild rivers; before irrigation sucked rivers dry; before timber harvest robbed rivers of their protective forests; before fishermen's nets swept through the rivers and bays; before humans walked across the Bering Strait and into the Pacific Northwest; before glaciers gouged out Puget Sound; before the Oregon coast migrated away from Idaho; before all this, there were the salmon.

In the Linnean system for classification of plants and animals, the Pacific salmon fall into the family Salmonidae and the genus Oncorhynchus, the Pacific salmon and trout (Appendix A). The name "Oncorhynchus," from the Russian term for "hooknose," refers to the hooked upper jaw that males develop during mating. There are seven species of Pacific salmon within the genus Oncorhynchus. Five are found in North America: pink (O gorbuscha), chum (O. keta), sockeye (O nerka), coho (O kisutch), and chinook (O. tshawytscha). Two are found only in Asia: masu (0. masou) and amago (O. rhodurus). Pacific trout within the genus Oncorhynchus include the anadromous steelhead, O. mykiss, and sea-run cutthroat trout, O. clarki. The five species of Pacific salmon and the two anadromous trout have evolved a rich array of life histories and local and regional distributions, which are summarized in Appendix B.

Native Americans sometimes called the salmon "lightning following one another," a name that evokes an image of the large silver fish flashing through swift water. Our culture's most common image of the salmon is of a fish climbing the face of a seemingly impassable falls, wiggling and fighting for purchase to launch another jump. We associate the salmon with a strong, fighting spirit and an unstoppable determination to return to the stream of their birth to create the next generation. Our image fosters the belief that the salmon possess an inherent ability to persist regardless of obstacles. But their persistence is more than just legend. Nature and, more recently, humans have repeatedly created conditions that threatened the salmon's survival, yet they have persisted.

All organisms are historical phenomena, and the salmon are no exception. For thousands or even millions of years, the salmon have accumulated the history of their species and retained it in the gene pools of individuals and populations. As a result, the salmon's genetic program, coded in its DNA, is a textbook containing thousands of years of evolutionary experience—lessons on how to survive in a harsh, changing world. That the Pacific salmon have survived our largely unrestrained assault on them and their habitats over the past 150 years proves the value of the lessons each salmon carries in its genes. And it is precisely because the salmon are such tough, persistent animals that their catastrophic decline in California, Oregon, Washington, and Idaho is so tragic. Once we understand the salmon's story, we can see their collapse as a clear testimony to the failure of our management institutions and to the rapid and massive habitat destruction over the past century. To fully appreciate the salmon's resilience, we must understand their evolutionary history and the episodes of cataclysmic environmental change they have survived.

A Rough Trip through Evolutionary Time

The Pacific salmon belong to a group of fishes whose branch on the evolutionary tree sprouted relatively late, about 400 million years ago. Within a short 40 million years these newcomers, the ray-finned fishes, came to dominate many freshwater habitats and were well on their way to dominating the sea. The ray-finned fishes comprise three main groups, and each achieved prominence for a time. Sturgeons and paddlefishes are the surviving members of the oldest group, and the gars give us a glimpse at the second group. Teleosts are the last and still prevalent group, which includes familiar fishes such as salmon, trout, perches, pikes, and catfishes. The fossil record shows that teleosts arrived relatively late in western North America. They did not dominate western fresh waters until about 55 million years ago.

Teleosts, like the other fishes before them, rose to dominance because they evolved improved structural and physiological features that gave them a competitive edge. The teleosts acquired a more efficient respiratory system, and their body form and musculature changed to permit more rapid and complex movement—important survival traits for both prey and predator. Among these efficiently designed fishes is the family Salmonidae, which contains salmon, trout, whitefishes, graylings, and ciscoes.

No one knows just when the Salmonidae split off from other ancient teleost fishes, but the family might be 100 million years old. That means ancestral salmon could have swum in the same waters used by dinosaurs during the last few million years of their reign on earth. The earliest confirmed Salmonidae fossil is Eosalmo driftwoodensis, whose bones were found in Eocene sediments of British Columbia (Appendix C). It resembled the modern grayling and lived in ancient lakes of western Canada about 40 to 50 million years ago. Based on the fossil record, Salmonidae's prehistoric range in western North America extended as far north as the Yukon Basin (66° north latitude) and as far south as the Lake Chapala Basin of Mexico (31° north latitude).

Native fish fauna in the Pacific Northwest survived a rough trip through evolutionary time. No other region in North America has been as geologically active as the Pacific Northwest, which means no other region has experienced the same degree of habitat and environmental transformation. Mountains rose, the coastline migrated, the climate changed drastically, and volcanoes flooded large areas of the region with thick layers of molten lava. Many fish species—pikes, freshwater catfishes, bass, sunfish—did not survive the monumental geologic and climatic changes. But the tough and tenacious salmon endured, and their resilience is still a source of hope for the future.

Origins of Anadromy

Salmon are anadromous. Adult salmon spawn, their eggs incubate, and juveniles rear for a few weeks to several years in fresh water. Then the juveniles migrate to the saltwater sea, where they spend a few months to several years...