Spring climate and summer otolith growth in juvenile Arctic charr, Salvelinus alpinus

The influence of different climate variables on the first four years of otolith growth in Salangen Arctic charr, Salvelinus alpinus, was studied over the period 1939-2005. Salangen is a coastal, low altitude, subarctic lake system located in northern Norway. Climate data, including water temperature, air temperature, ice-cover and precipitation, were available for most of the 67 year period. Water temperatures in May and June had a significant effect on otolith growth during the second growth year, while no relationship between otolith growth and climate variables was found for the first, third and fourth years of otolith growth. Otolith increment size during the third and fourth growth year was autocorrelated with growth during the previous year. Spring snow fall and timing of ice break-up had an indirect effect on growth, as these variables were highly correlated with spring water temperatures. High variation in otolith growth within years and among individuals suggests that individual and age-specific variations in spatial habitat use may confound the direct effects of changing air temperatures and time of ice break-up.