Timing of Spawning in Norwegian Atlantic Salmon (Salmo salar)

Abstract

A hypothesis that thermal regime regulates the timing of spawning in Atlantic salmon (Salmo salar) was analysed by correlating time of commencement and peak of spawning in 16 Norwegian streams with temperature, latitude, and stream flow. Only temperature during incubation of the eggs proved to have any statistically significant effect. Since the duration of egg incubation is known to depend on temperature regime (i.e. on degree-days), a similar linking of spawning time to stream temperature allows spawning to occur at a time which will result in hatching of eggs at a specific and presumably optimal time for survival of fry.