Diving behaviour of Antarctic fur seal (Arctocephalus gazella) pups
The diving behaviour of Antarctic fur seal (Arctocephalus gazella) pups on Bird Island, South Georgia (54°S, 38°W), was examined during February-April 1996 using capillary-tube depth gauges (CDGs) and time-depth recorders (TDRs). CDGs were deployed on 6 female and 10 male pups aged 65-101 days. Depths measured by CDGs were within 10% of maximum depths recorded by TDRs. Maximum dive depths averaged 13.8 m and ranged from 4.2 to 28.1 m. Body length alone accounted for 66% of the total variation in maximum dive depth. TDRs were deployed on one female and two male pups aged 89-101 days. In total, 4858 dives were recorded during 173 h at sea. The average dive depth and duration was 4.2 m and 20 s, respectively. Pups made a total of 34 trips and each spent 50% of its time at sea. Not all trips included dives; however, when diving took place trips lasted, on average, 6.8 h and contained 214 dives, most of which took place during daylight. Dives were made at a frequency of 30/h and the vertical distance dived was 124 m · h-1. The number of dives, percentage of time spent submerged, percentage of time spent diving, dive frequency, and dive rate were positively correlated with trip duration. These results show that Antarctic fur seal pups develop diving skills at an early age, and by the time they are close to being weaned they have the diving ability to exploit prey similar to those taken by adults.