Salmon divergence. Salmon eggs are laid in freshwater streams typically at high latitudes. The eggs hatch into alevin or sac fry. The fry quickly develop into parr with camouflaging vertical stripes. The parr stay for six months to three years in their natal stream before becoming smolts, which are distinguished by their bright, silvery colour with scales that are easily rubbed off. Only 10% of all salmon eggs are estimated to survive to this stage. The smolt body chemistry changes, allowing them to live in salt water. While a few species of salmon remain in fresh water throughout their life cycle,
Salmon run its birth, spawning, and then dying. Semelparous animals spawn once only in their lifetime. Semelparity is sometimes called "big bang" reproduction, since the single reproductive event of semelparous organisms is usually large and fatal to the spawners. Most Atlantic salmon also die after spawning, but not all. About 5 to 10%, mostly female, return to the ocean where they can recover and spawn again. In the Pacific Northwest and Alaska, salmon is a keystone species, supporting wildlife from birds to bears and otters. The bodies of salmon represent a transfer of nutrients from the ocean, rich in nitrogen, sulfur, carbon