The "starburst" wiped out the dinosaurs, but not the salmon
The salmon's predecessor is 80 million years old. The "Starburst" 65 million years ago wiped out the dinosaurs and half of all species. The salmon survived by using the sea to find enough food. Land uplift after the last ice age meant that some salmon live their entire lives in freshwater.
72% of the earth is covered with water. Fish live in water - some in saltwater, others in freshwater. All fish have a common starting point. Over time, they have evolved into different species and families. The life of the salmon started in freshwater.
By studying our genetic material - the genes, the building blocks that determine whether we become human, animal or fish - we can find out when a species came into being. We get half of our genetic material from our mother, the other half from our father.
More than 100 million years ago, what we know today as pike and salmon began to evolve in different directions.
80 million years ago, a very special egg was laid. Out of the egg came a fish with all the genetic material from both mother and father. He was the predecessor of all salmonids - a genetic mutant. This doubling of the genetic material, known as gene duplication, made the fish better able to adapt.
65 million years ago, the Earth was subjected to a "starburst". A 15-kilometer-wide asteroid hit the Earth. More than half of all living species became extinct. The dinosaurs died, but the fish adapted - and survived.
50 million years ago, the species of grayling and whitefish separated from the salmon tree. The first fossil, of a 15-centimeter-long salmonid, was found in North America. It is 50 million years old.
At some point between 50 and 20 million years ago, an increasingly cold climate probably forced fish to migrate from freshwater to the sea to find enough food to survive and grow. Fish that migrate between fresh and salt water during their lifetime are called anadromous.
20 million years ago, some salmon were isolated on the western side of the American continent. This led to the division between Pacific and Atlantic salmon.
Between 5 and 10 million years ago, the aurochs, char and salmon went their separate ways. The char probably predates the aurochs.
About 2 million years ago, salmon migrating into the Atlantic Ocean (Atlantic salmon) became the salmon we know today.
Around 10,000 years ago, as soon as the rivers in Norway were formed after the last ice age, char, salmon and aurochs established themselves in them.
As the ice melted, the land rose. The land uplift 9500 years ago led to salmon being isolated in freshwater in four places in Norway. Two of these salmon, the Namsblanken and the Byglandsbleka, are still here. They both belong to the Atlantic salmon species, but have "gone back to the start" and once again adapted to a full life in freshwater. We call them relict salmon stocks.