Salmon run plankton. At this point the baby salmon are called "fry". At the end of the summer the fry develop into juvenile fish called "parr". Parr feed on small invertebrates and are camouflaged with a pattern of spots and vertical bars. They remain in this stage for up to three years. As they approach the time when they are ready to migrate out to the sea the parr lose their camouflage bars and undergo a process of physiological changes which allows them to survive the shift from freshwater to saltwater. At this point salmon are called "smolt". Smolt spend time in
Atlantic salmon smolt, grilse, grilt, kelt, slink, and spring salmon. Atlantic salmon that do not journey to sea are known as landlocked salmon or ouananiche. Atlantic salmon are the largest species in their genus, "Salmo". After two years at sea, the fish average in length and in weight. But specimens that spend four or more winters feeding at sea can be much larger. An Atlantic salmon netted in 1960 in Scotland, in the estuary of the river Hope, weighed , the heaviest recorded in all available literature. Another netted in 1925 in Norway measured in length, the longest Atlantic salmon on record.