Alaska has five species of salmon and we all know that they fight valiantly to swim upstream from the ocean, even scaling waterfalls to reproduce at the very stream where they were hatched. But what about their journey downstream? Don't they face the same dangers? This exhibit traces the life of salmon, starting as eggs.
Their nest (or "redd") can be up to 18 inches deep and contain up to 8,000 eggs. The water's temperature, level of oxygen, and speed can affect those eggs' development (as can predators like raccoons, bears, birds, and crawfish). The eggs will incubate for up to 50 days, when the babies (known as "alevin") will emerge. Too weak to brave the currents, alevin must hide for several weeks in the gravel beds as they continue to grow, taking nourishment from the yolk sac that is still attached to them. They're now known as "fry," they're still only about one inch long. Chum and Pink fry will immediately begin to journey downstream to the ocean, slowly maturing along the way. Chinook will remain in the stream for six months or so, while Coho wait a year before making the journey. And sockeye will stay in the stream for one to three years before heading to sea. As the fry grow and make their way downstream into the coastal areas called estuaries, where the freshwater and saltwater mix, they become known as "smolt." But at their current size they're easy prey, and the mortality rate for this stage of a salmon's life is extremely high. When their bodies have fully adapted to living in saltwater, the salmon head out into the open ocean, where they will spend the next one to six years feeding on small bait fish and traveling thousands of miles away, until nature signals to them to return to their birth stream.
By the way, the best way to remember Alaskan salmon is to look at your hand: your thumb stands for Chum (Oncorhynchus keta) also known as Dog or Calico salmon; your pointer finger could "sock" someone in the "eye," standing for Sockeye (Oncorhynchus nerka) or Red salmon; like your middle finger, Chinook or King salmon (Oncorhynchus tshawytscha) is the largest; the ring finger can be adorned with a silver ring, like the Coho (Oncorhynchus kisutch) or Silver salmon; and the pinky is the Pink salmon (Oncorhynchus gorbuscha) or Humpies.