Salmon divergence. Salmon eggs are laid in freshwater streams typically at high latitudes. The eggs hatch into alevin or sac fry. The fry quickly develop into parr with camouflaging vertical stripes. The parr stay for six months to three years in their natal stream before becoming smolts, which are distinguished by their bright, silvery colour with scales that are easily rubbed off. Only 10% of all salmon eggs are estimated to survive to this stage. The smolt body chemistry changes, allowing them to live in salt water. While a few species of salmon remain in fresh water throughout their life cycle,
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