Transgenerational effects of egg nutrients on the early development of Chinook salmon (Oncorhynchus tshawytscha) across a thermal gradient

Abstract

The transgenerational effect of maternal diet, expressed as variation in the composition and quantity of egg nutrients available to offspring during endogenous development (i.e., prior to free-feeding), has the potential to greatly influence the response of offspring phenotypes to varying environmental conditions. For this study, we examined how natural variation in the fatty acid and proximate composition of eggs from three Chinook salmon (Oncorhynchus tshawytscha) populations influenced early development across a thermal gradient using a common garden hatchery experiment. We found that the relative quantity of fat, lean mass, and water in the eggs was similar among populations. However, the fatty acid composition of the eggs differed among all populations. After controlling for egg mass, egg fatty acid and proximate composition influenced hatch length, swim-up length, and hatch to swim-up growth. Importantly, the magnitude and direction of these egg quality effects depended on the population of origin and temperature. Overall, our results demonstrate that natural variation in egg nutrient composition, likely driven by maternal diet, has transgenerational effects on offspring development under varying thermal conditions.