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
Salmon louse gills of the fish, and feeding off the mucus or skin. Sea lice only affect fish and are not harmful towards humans. Salmon lice are natural ectoparasites of salmon, in the 1980s high levels of salmon lice were observed on Pink salmon smolts. Salmon lice are found in Pacific and Atlantic Oceans, they infect Pink salmon, Atlantic salmon, and Chum salmon. There has been some research on the problems caused by this species in aquaculture, but little is known about the salmon louse's life in nature. It has been shown, however, that salmon louse infections in fish farming facilities can