Over the past decade USDA’s National Marine Cold Water Aquaculture Center (NMCWAC) has experienced declining egg quality. The NMCWAC located in Franklin, Maine houses an applied selective breeding program, where the primary objective is to improve S. salar lines for aquaculture production. Egg quality is crucial as it sets the scene for onsite productivity and provides multiplier eggs. The first-time quality is observed by industry, is termed “eye-up”, which coincides with the developmental benchmark where eyes are boldly visible through the chorion. Eye-up marks the first time eggs are handled since fertilization, and survival is determined. To further investigate the intrinsic differences that may influence S. salar performance throughout ontogeny we determined routine metabolic rates (RMR) of 16 families. RMR is defined as the energetic cost required to power an individual’s baseline living. Metabolism of embryonic and larval fishes was used as a tool to gain insight into the energetics, tolerance, and survival. Utilizing offspring from 2023 broodstock we investigated four developmental timepoints; pre-eye, eye-up, post eye-up, and alevin stages while recording metrics of egg & alevin size (cm3, weight (g)), mass specific metabolism (Mg02/g/hr-1), and survival (% eye up). Trials took place daily for a duration of 3 hours at optimum rearing temperatures (8°C), where oxygen consumption was recorded with oxygen sensors. As a result, small scale variation of metabolism was defined, where differences of rates across families were minute.