Time budgets and foraging characteristics of lactating Antarctic fur seals

For Arctocephalus gazella at Bird Island, South Georgia, mean duration of foraging trips was 121 h and 100 h in 1988-89 and 1989-90, respectively, while periods ashore were 55 ha and 45 h, respectively. There was a significant difference between these variables in the two years but there was no significant difference in the percentage of time spent at sea. In both years, there was significant variation between individuals in the foraging-attendance time budget. There was a positive correlation between mean time spent ashore and mean time spent at sea for individual seals. The foraging-attendance patterns of seals changed significantly with time through lactation in one year of the study but not in the other. Duration of foraging trips or the period spent ashore had no effect on pup growth rate. During short foraging trips (1-2 d) seals dived for a greater proportion of the time available for foraging than during longer foraging trips (>3 d). Seals fed predominantly on krill during both years. Most foraging occurred at night, reflected in diel variation in times of arrival and departure of seals. Seals were normally feeding 60-90 km away from Bird Island. -from Authors