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,
Healthy Life Years asked concerning the longstanding activity limitation is: "For the last six months, to what extent have you been limited because of a health problem in activities that people usually do?" Some available answers are "severely limited", "limited but not severely", or "not limited at all". The indicators used to calculate a person's healthy life years are self-reported to a certain extent and therefore would be considered limited. The collected data is affected by the respondent's subjective perception as well as by their social and cultural background. That is because people from different social backgrounds like different cultures, race and ethnicity,