how lipids may be utilized during embryonic development, and how lipid catabolism is altered by temperature are unknown. Recent studies have shown that incubation at different temperatures influences survival, whole embryo physiology, and energy use of lake whitefish (Eme et al., 2015; Lee et al., 2015; Mueller et al., 2015). In particular, an increase in temperature from 2 to 8 °C decreased yolk conversion efficiency and increased cost of development in lake whitefish embryos (Mueller et al., 2015). We hypothesized that weight percentage lipid content of lake whitefish eggs would decrease during embryonic development, indicative of lipid catabolism. We also hypothesized that at lower incubation temperatures, PUFA would be selectively retained and that this may be related to the maintenance of membrane integrity, i.e. homeoviscous adaptation, at near freezing temperatures.