Then, for a period of two to five years (depending on the species), that fish must circulate through the Sea of Okhotsk or else southeastward around the peninsula's tip into the expanse of the Pacific. The fish might travel thousands of miles, finding its preferred food (mostly small squid and crustaceans) abundant but facing predation, competition, and other challenges of the marine environment. For instance, it might be caught in the open ocean by fishermen using enormous drift nets that trap everything in their path. If it survives these years of robust swimming and feeding, it will grow large, fat, and strong. That's the advantage of anadromy (a sea-run life history): The ocean years allow fast growth. Approaching sexual maturity, the fish will head homeward to spawn, using some combination of magnetic sensing and polarized light to find its way back to the Bolshaya River. From the estuary it will ascend upstream by smell, branching into the familiar Bystraya, and finally climbing through the same shallow riffles of the same smaller tributary that its parents ascended before it.
Thousands of eggs will be laid for every two adult fish that return. Unlike an Atlantic salmon or most other species of vertebrate, a Pacific salmon breeds once and then dies. Scientists call the phenomenon semelparity. For the rest of us: big-bang reproduction. After the adult has homed to its spawning stream, death follows sex as inexorably as digestion follows a meal. It's a life-history strategy, shaped by evolution over millions of years, that balances the costs of each spawning journey against the costs of reproductive effort, toward the goal of maximizing reproductive success. In plainer words: Since the likelihood of any fish surviving the whole journey not just once but twice is so slim, Pacific salmon exhaust themselves fatally—they breed themselves to death—at the first opportunity they get. Why hold back anything if you'll never have another chance?
So their lives enact a romantic but pitiless narrative. Their success rate is low, even under optimal circumstances. The miracle of salmon is that any of them manage to complete such an arduous cycle at all. And present circumstances on the Bolshaya River and its tributaries—though the wall poster at Malki didn't say so—are far from optimal.
Ludmila Sakharovskaya, director of the Malki hatchery, is a sweet-spirited woman with blond hair and silver glasses who has worked there since the early 1980s. She trained as a biologist in Irkutsk, a warmish city in south-central Siberia, before moving east to this severe outpost in search of a better livelihood. For almost three decades she has watched—she has lived, like a doting nanny—the cycles of salmon rearing, release, and return.