Smolt

... is the last freshwater stage in the life cycle of the Atlantic salmon, before (and during) its migration to the sea. It comes after the 'parr' stage (a young salmon, less than three years old, that has not yet left its native stream) and the 'grilse' stage (a young salmon after one winter at sea). After two or more winters at sea, a salmon is considered to be mature and is simply called a salmon.