The life cycle of a salmon doesn’t happen by chance. The instincts of a salmon to find the river it came out of before spawning are amazing. Once the female salmon decides it has reached its place of spawning, it digs a shallow redd in the riverbed. A Redd is a hollow in a sandy or gravel river bed. A salmon usually finds a spot to dig out with its hooked nose. The redd becomes a nest of sorts for the salmon to lay its eggs. Redds are easily destroyed by animals or humans crossing the river, as well as dirt being washed over the eggs. Clearcut logging too close to a river can cause dirt to erode off the surrounding land into the water shed.
Salmon need 2-3 months to hatch out of the egg. During this period, their eyes and other organs can be seen developing through the translucent shell of the egg.
Colder water can mean a longer incubation period.
Once the salmon is hatched, it is called an Alevin and is about 1 inch in length. It carries a yolk sac which is like its lunch bag. The yolk sac provides vitamins, sugars, minerals and protein necessary to carry out its first few months while it develops its mouth, digestive system and excretory organs. It is completely depended on this sac for survival. During this few months, the Alevin hides in and around the gravel nest until the sac is completely absorbed. When it emerges from the nest, it is about 1.5 inches long.
Once the Alevin consumes its egg sac it is called a fry. It is now ready to leave the gravel area in the stream bed and look for food. The fry must hide around rocks and among vegetation to avoid birds, insects and other fish. However, they still need to feed to survive. Chum and Pink salmon take off immediately to the ocean.
Once the salmon starts to get its vertical markings, it is called a Parr. It is in this stage that the 3 other species are getting bigger in preparation for salt water. Chinook wait up to six months while Coho can hang around for as long as one year. Sockeye stay for 1-3 years before beginning the journey to the sea. As mentioned on the sockeye page, they need to be raised in a freshwater lake which is different from the other types of salmon.
When a juvenile salmon loses its vertical markings on its body and turns silvery in color, it is now considered a Smolt. They start schooling together in large groups and at this time the young salmon will adjust their bodies to saltwater, allowing them to swim out into the Pacific Ocean to feed and grow into adult salmon.