Tr. Walker et al., SEASONAL OCCURRENCE AND DIET OF LEOPARD SEALS (HYDRURGA LEPTONYX) AT BIRD ISLAND, SOUTH GEORGIA, Antarctic science, 10(1), 1998, pp. 75-81
Seasonal haul-out patterns and diet of individually marked leopard sea
ls (Hydrurga leptonyx) were investigated at Bird Island, South Georgia
during the 1983-96 winters. A total of 2956 leopard seal sightings we
re made, and 121 seals were tagged during the study, mainly between 19
93 and 1996. Photographs of scars and pelage patterns were also used t
o identify a subset of these individuals across years, which provided
no evidence of tag loss between or within years. Leopard seals were ob
served between April and November; the mean time between the first and
last sightings in each year was 208 d (s d +/- 48). Between 1993-96,
eight seals were resident around the island for more than 100 d, and t
he longest recorded residence was 130 d. The proportion of tagged seal
s resighted was 0.35 and 0.17 in 1995 and 1996 respectively. Based on
estimates of body length, <5% of the seals were juveniles (0-1 years)
and >70% were not sexually mature. There was considerable inter-annual
variation in abundance, with a maximum of 502 sightings during 1994,
compared with a minimum of 21 during 1986 and 1989. Antarctic fur seal
s (Arctocephalus gazella) were the main prey item (58% of kills observ
ed and 53% of seats). Other items included penguins (28% of kills obse
rved and 20% of seats) and fish (24% of seats). Antarctic krill (Eupha
usia superba), southern elephant seals (Mirounga leonina) and seabirds
other than penguins were also present in the diet in small quantities
.