After a few years in the river, the small salmon's body undergoes major changes. It prepares itself to withstand salt water. When the salmon is ready to travel to the sea, we call it a smolt.

When the pair has become about the same length as a ballpoint pen, we can call it a juvenile. Now the transformation is underway. Major changes occur both on the outside and inside the body. The pair transforms into a smolt, and this is called smoltification. On the outside, it becomes longer, slimmer and shiny. Inside the body, things happen that allow it to live in salt water without drying out. It excretes the salt through its gills and when it urinates.

The smolt is now ready for the sea. The river current carries it down the river. At the bottom of the river they gather in larger and smaller groups. They never leave the river alone. It is safer to swim together in a school. Because they are slender, they can swim fast. Because they are shiny, they are less visible when swimming in clear seawater. And because there are more of them, it is more difficult for birds and other fish to catch them.

The school of smolts swim out through the fjord quite quickly. Some have to go through long fjords, while others have a short way to the sea.

It is spring when the smolt leave, but the smolt in the south migrates to the sea earlier than the smolt in the north. We still do not fully know what determines when the smolt leaves the river.

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