Does aerobic dive capacity constrain winter diving behavior in crabeater seals?
Jennifer M Burns1 and Daniel P Costa2 1 Biological Sciences, University of Alaska Anchorage, Anchorage, AK 2 Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA ABSTRACT During austral summers, crabeater seals (Lobodon carcinophagus) preferentially target the large zooplankton and krill that are abundant in surface waters. However, during winter months, seals forage deeper and closer to the seafloor, where their preferred prey aggregate. As a result, winter foraging is associated with a much greater proportion of dives longer than the seals calculated aerobic dive limit (cADL, 6.1 – 11.8 min). To determine if aerobic capacity constrains winter foraging activities, we examined the relationship between the cADL and dive depth, bottom time, and bathymetric depth in 34 crabeater seals ranging in mass from 118 – 365 kg. While fewer than 10% of dives shallower than 150 m were anaerobic, this percentage exceeded 30% for dives deeper than 250 m. These deeper d
