Migrations in an extreme northern population of Arctic charr Salvelinus alpinus: Insights from otolith microchemistry

Abstract

Growth and migrations of Arctic charr from a Norwegian Arctic lake system were examined using structural and chemical characteristics of their otoliths as indicators of physiological and habitat characteristics. Measurements of otolith strontium/calcium concentration ratios by wavelength dispersive electron microprobe clearly revealed salinity migrations and provided a life history profile for individual fish. There was wide range in the age at first seaward migration (4 to 13 yr; mean 6.7 yr). Sr/Ca concentration data were also used to determine that a few migratory charr occasionally abstained from seasonal migrations. Microchemical techniques are an innovative approach to life history analysis when used in combination with structural analyses of otoliths from migratory fish.