The experiments dealt primarily with routine metabolic rates of schooling juvenile Atlantic menhaden,Brevoortia tyrannus(Latrobe), in flowing‐water respirometers and were designed to obtain baseline data for energy flow models and studies on the effects of sublethal stresses. The relationship of body weight to oxygen consumption as well as the effect of temperature (10–25°C), salinity (low, 5–10 p.p.t. and high,>28 p.p.t.), time since last fed and darkness on the routine metabolic rate was examined. The effect of salinity on growth of menhaden larvae into juveniles was also me