Individual Mass Dynamics

• Mass dynamics are based on a von Bertalanffy growth curve defining a gender and age-specific target mass.
  

• The requirements and efficiencies of converting prey or body mass into energy, and using that energy to support field metabolic rate (FMR) or somatic production are similar to those used by Winship et al. (2002) for Steller sea lions (Eumetopias jubatus). We make the simplifying assumption of a constant ratio of lean to fat tissue in the body of killer whales with an energetic value of 3.4 kcals/g.
• The energetics of transient killer whales are based on the estimates of field metabolic rate (FMR) for delphinids (Williams et al. 2005): FMR = 405.39 × M^0.756 kcals/day, where M = mass in kg. Metabolic and catabolic conversion efficiencies are similar to those suggested by Winship et al. (2002), though few are based on killer whale studies and many are poorly known in any marine mammal. The requirements for fetal growth and lactation, including the efficiencies in the figure below, are added to the female's FMR when determining the daily energetic maintenance requirements.