This project uses experimental methods to quantify the effects of environmental factors on success of early life-stages of marine fishes. Each year we are involved in new experimental studies that help fisheries scientists better understand and model processes important to fish population dynamics. Our primary focus is on processes that occur during the early life (eggs to young juveniles) of marine fishes simply because the vast majority of deaths and perhaps most natural selection occur at those ages. We employ a broad definition of ‘environmental factors’ to include physical variables (e.g., temperature, salinity), biotic variables (e.g., feeding regimes, predation risk), as well as genetic and non-genetic parental influences (e.g., maternal investment in egg size, parental care). We also quantify ‘success’ broadly to include rates of survival, growth, development, and metabolism; condition; and behavior of young fish. The typical protocol would entail the spawning of fish, implementation and application of treatment(s) (i.e., environmental factors) to embryos, larvae, and / or juveniles, and then identifying / developing metrics that are appropriate outcomes to measure in the context of study. We recently used two different species of flatfish to address questions concerning i) thermal effects on morphometric variation of larvae during ontogeny and ii) maternal influences on offspring quality. This project typically takes advantage of the synergism provided by concurrent activities in our research group that also use the same species. Candidate species for 2019 include summer flounder, winter flounder, Atlantic silverside, Atlantic killifish, and horseshoe crab. Response metrics of special interest this year are growth, development, metabolic and consumption rates, behavioral responses, and predation risk.