context: Salmon is a true hiking fish. Salmon from the Bothnian Bay depart for the sea, where they arrive in June and reach the main basin of the Baltic Sea as early as September. Hiking from the Baltic to the North Sea is very rare, but it does. The longest known hiking trip was from the Bothnian Bay to the west coast of Greenland, over 5000 km.
question: How Long Can Salmon Hike?
answers.text: over 5000 km