Standard metabolic rates (SMRs) for Atlantic salmon (Salmo salar) have been calculated independently for different life stages and populations, but the absence of a comprehensive SMR model limits its application for modelling the energy use or life stage-specific growth. Atlantic salmon respiration data were compiled from a meta-analysis of 26 publications, and exponential or optimal relationships were fitted to the metadata to estimate respiration equation parameters and generate confidence intervals dependent on temperature and body mass. While model parameters were significant for both models, mass-corrected standard metabolic rates (g O 2 ·day −1 ) increased as a function of water temperature (°C) and decreased beyond ∼16 °C following an optimal relationship (AIC optimal = –9185.50 versus AIC exponential = –8948.95; ΔAIC = 236.55). Juvenile Atlantic salmon growth (cohorts 1 and 2) from bioenergetics simulations did not vary between Little Southwest Miramichi and Northwest Miramichi rivers; however, variation between simulations using the different respiration models (i.e., exponential versus optimal) led to differences in the way fish allocate energy throughout the year. Results from this analysis will inform conservation efforts for the species throughout its current range and predict the energetic requirements at juvenile life stages.