1. Salmon Five Facts About Salmon 1)Their life span is about 2-8 years 2)Their eggs take about 6-12 weeks to hatch 3)Salmon grow in maturity in about 1-2 years 4)Some salmon migrations range about 1-5 years 5)The physical changes that take place in a salmon is that it will sometimes change from bright silver to bold or much darker body colour. Salmons need to lay a lot of eggs at the same time as few salmons reach adulthood as once they are born, they are eaten by their predators. One of the behavioral adaptations of salmon is smoltification, a process of which the salmon adapts to more salty waters instead of freshwater lakes. As this takes quite a long time, the salmon is in a weak state and therefore is an advantage to it’s predators like river otters, Caspian and Artic terns, gulls and larger fish even sea lions and seals.