Studies on European grayling focus on an interesting lake system in Norway in which European grayling have been introduced in the recent past. The lake has many streams in which the grayling spawn, but the streams have vastly different temperature profiles. This suggests a rapid adaptation to different thermal profiles during early life stages. We are examining proteins during development and comparing the protein expression of the different spawning populations reared in a common environment. Additionally, my collaborators at the University of Oslo (Asbjørn Vøllestad, Thrond Haugen) are determining the genetic differentiation of these populations and their stability through time.