Early developmental stages of cold-adapted ectotherms such as brook trout
(Salvelinus fontinalis) are at risk of mortality with increasing water temperatures because
of their sensitivity to changes in their environment. I studied the mass and routine
metabolic rate (RMR) of wild-origin brook trout eggs, alevin and young fry reared at
normal (5°C) and elevated (9°C) temperatures for the duration of the study or at
mismatched temperatures. This setup determined if preconditioning acclimation for one
temperature benefits or hinders the organism later in life. Three levels of biological
organization (ancestry, population, family) were studied using Akaike's Information
Criterion (AIC) to identify models that best accounted for variation in the data. Family,
mass and temperature were most important in predicting body mass and mass-adjusted
RMR, although population and ancestral-level differences were also detected at some life
stages. Strong variation in body mass and mass-adjusted RMR among families may
indicate adaptive potential within brook trout populations to respond to increases in water
temperature with climate change.
Author Keywords: Acclimation, AIC, Brook trout (Salvelinus fontinalis), Environmental matching, Routine metabolic rate, Temperature