Migration usually occurs during the night hours. When smolting, young salmon will lose their parr markings and develop a more silver colour. An extra year may be spent in fresh water if condition are not favourable to healthy, fast growth. Growth is very fast once saltwater is reached. However, added pressures from predators decrease survival rates.
Ocean life can be very difficult for growing salmon.
They travel long distances and encounter many dangers. Generally smolts tend to migrate northwards along the coast and will reach coastal Alaska by late summer. The southerly return migration occurs after about 12 months at sea. Many coho will swim a counter-clockwise circuit around the Gulf of Alaska. The route of migration is highly dependent on where the salmon find good feeding grounds.