The Atlantic salmon (Salmo salar) has long been identified as a threatened species. In order to better understand its life cycle, long-term monitoring of the salmon population in Girnock, Scotland, a well-known freshwater habitat of this migratory fish species, was started around sixty years ago. The work is the most detailed long-term study of an Atlantic salmon population in the world. It revealed quantitative changes in the return rates, distribution, size, growth and age of salmon.
