"I love Salmon but can't bring myself to buy it after Fukushima..the waters are contaminated now. "
Making these estimates requires understanding the unique life cycle of salmon. The sockeye that I held on Mike Poole's boat, for instance, probably hatched from the gravel bed of a clear forest stream hundreds of miles up from the Copper River Flats. (About a quarter of Alaskan sockeyes are hatchery raised, then released into the same river systems.) As a young fish, she made her way downstream, then headed out to sea, scarfing down tiny crustaceans and packing on pounds. Programmed for wanderlust, she roamed across the north Pacific. And somehow found her way back, five years later. Once she closed in on the mouth of the Copper River, she could smell home. Loaded with nutrients from her years at sea, she prepared to make her last journey, during which she would not eat. If she hadn't had the misfortune of running into Mike's gill net, she would have powered her way 300 miles upriver, gaining a thousand feet of altitude, fighting the seven-knot current all the way, responding to her earliest smell memories until she was within a few feet of the exact place where she was born. There, surrounded by others of her generation, and accompanied by the male of her choice, she would have picked her spot, turned sideways, beat away a depression in the river bed with her tail, and laid her eggs. After the male sprinkled sperm over the top, she'd have swept gravel over the nursery. And then, her life's mission complete, she'd die within days.
Keeping salmon populations sustainable is simply a matter of letting enough of them complete that spawning journey to seed the next generation. Unfortunately, on most of the world's salmon rivers—which once included almost all the rivers of the northern U.S., Canada and Europe—dams have made that impossible. They have been the kiss of death for some extraordinary salmon runs, including the Columbia, which once may have held 16 million salmon, but now holds just 2 million. "When they put those dams in," Bert Lewis says, "they made a choice to have cheap electricity instead of salmon." So far, Alaska has chosen abundant salmon and expensive electricity.