Whether you're a gourmet diner or interested in culture or nature or how indigenous peoples make a living, you're going to be fascinated by UPSTREAM: SEARCHING FOR WILD SALMON FROM RIVER TO TABLE. Starting with the first day of salmon fishing and the fishmarket on the street in Seattle, the author Langdon Cook, who previously gave us a study of 'The Mushroom Hunters', takes us through the story of the most prized fish.

Most Atlantic salmon has been fished out or lost habitat, and been replaced by farmed salmon. Needing to spawn in a pristine stream makes the large fish vulnerable. The Pacific salmon is divided between the smaller, more plentiful sockeye salmon and the large, scarcer and more valuable king salmon. As the king travels at the bottom of the inlet water column, the nets to catch salmon are set higher, catching mostly sockeye. Those kings which are also caught may weigh up to eighty pounds and, dressed, can be worth a thousand dollars for two. But price alone is not all their value; these impressive fish feed native peoples as fresh and dried or smoked food, and the dead, spawned- out headwater fish feed bears, big cats and wolves as well as birds. The bodies of the fish bring invaluable nutrients up from the ocean to the mountainous land, passed on to fertilise the soil and nurture life.

Langdon Cook talks with the commercial fishermen, chefs and dealers whose livelihoods depend on the continuance of salmon fisheries. Copper River is one of the main fisheries but the Yukon River is praised by those in the know. Kevin Davis, restaurant owner, will only buy regulated US caught salmon, believing that otherwise the environmental costs will have to be paid by someone, sometime. Jon Rowley helped to put fresh Copper River salmon on the map - at the time it was all being canned.

The term anadromous means a sea fish that needs to spawn in a river, and Langdon Cook travels to the Columbia River to try catching his own fish. Latest estimates are that thirty million salmon used to spawn here annually; like the passenger pigeon, their numbers were reduced by human appetite and they now arrive a few thousand at a time. Huge dams were built, some without any salmon ladders. Wrecked oil tanker Exxon Valdez destroyed pristine Alaskan ocean habitat. With reduced resources comes competition and argument. A drying Pacific Northwest and reduced snowmelt means rivers are shorter and lower so salmon can't make it to gravel beds to spawn; there may be fewer in the future. We learn nicknames for different kinds of catch, like fall chinooks, chums, pinks and spring brights. And we learn that an Alaskan hatchery producing lower quality farmed salmon is mainly welcomed because the produce takes pressure off the wild salmon. Of course, salmon eat fish, so catching fish for the farm takes other fish off the market. It's never simple.

In a book about experiencing salmon, it's fitting to get recipes and alternative dining experiences along the way. UPSTREAM is an interesting, lively book, well worth a read for those who want to learn about the king of fish.