Estimating Food Requirements of Striped Bass Larvae: An Energetics Approach

Oxygen uptake by larval striped bass Morone saxatilis 12–22 d posthatch was converted to joules in order to estimate daily food requirements. I measured resting metabolism (in darkness), routine metabolism (in light without food), and active metabolism (with food) in contrasting treatments (dark-light, nonfeeding-feeding). Metabolism differed significantly between nonfeeding and feeding larvae but not between nonfeeding larvae in darkness and light. Ratios of active to resting weight-specific metabolism were 1.8 and 1.9 for younger and older larvae, respectively, and were below ratios commonly cited in the literature. Larvae needed an average of 2.06 J/d to grow and support metabolism, an equivalent of 57 Artemia nauplii or 73 copepod nauplii. Oxygen uptake and ingestion were slightly higher than previously published values for striped bass, possibly due to larger respirometers and faster gut evacuation times. The proportion of ingested energy metabolized was relatively high (35–50%), suggesting that striped bass larvae allocate considerable energy to activity.