As key components of freshwater (lake and river), estuarine and nearshore marine aquatic environments of the circumpolar north, Arctic char and related fishes of the genus Salvelinus are fundamental to the lifestyles and well-being of northerners as the basis for extensive fisheries conducted for household food (i.e., domestic and subsistence), commercial and sport purposes. Chars contribute significantly to household and wage economies, and social and cultural elements of northern life. Chars are also key integrators and indicators of the health of northern aquatic ecosystems, many aspects of which are at significant risk from increased climate variability and change. However, human adaptive responses are hampered by a lack of vital information regarding char thermal ecology, biodiversity and its functional significance in northern ecosystems, mercury and other pollutant interactions, and how these may respond to climate change.