CCAMLR

Zones of 20 km width are defined around selected colonies of penguins distributed around the coasts of the South Shetland and South Orkney islands. Krill catches in these zones are shown to have a consistent pattern in Subarea 48.1 but an unpredictable distribution in 48.2, probably as a result of oceanographic conditions. About 50% of the catch in 48.1 from December to March was taken within 40 km of the coast, and 90% within 80 km in all years 1988-1990. In 1987 and 1988 75% of the catch in 48.2 between December and March was taken within 80km of colonies in the South Orkneys. Estimates of consumption rates, foraging ranges and population sizes from the literature are used to show that for some years, months and zones of distance from the shore the catch of krill is 50% or more of the land-based predator consumption.

Published in J. Mamm., 72(1),000-000, 1991

The age distribution of breeding female Antarctic fur seals at Bird Island, South Georgia, in 1988 was compared with the age distribution of a sample obtained in 1971-1973. The mean age in 1971-1973 was 7.41 (SE = 0.26) years and in 1988 it was 6.93 (SE = 0.20) years. After correction for age-dependent arrival time at the pupping beach in 1988, the mean age was 6.22 (SE = 0.14 years), which was significantly lower than in 1971-1973. Indicators of population size suggested that population growth at Bird Island had declined to below 3% annually by 1988 compared with rapid growth (17%) in 1958-1972. Exponential models fitted to the frequency distribution of age-classes greater than age 5 years and corrected for the rate of increase of the population gave adult survival rates of 0.66 (SE = 0.03) and 0.88 (SE = 0.02) for the 1988 and 1971-1973 samples, respectively. The reduced apparent adult survival rate in the 1988 sample was probably caused by emigration brought about by high densities of females on the pupping beaches. There are few signs from this analysis that the fur seal population at South Georgia is close to carrying capacity.

We contrast the depth, duration and pattern of diving in the epipelagic-foraging Gentoo Penguin (Pygoscelis papua) and the benthic-foraging Blue-eyed Shag (Phalacrocorax atriceps). The daily foraging period was 8 hours in both species, but Gentoos spent 50% of this time diving compared to 20% in Shags. Shags had longer surface intervals between dives than Gentoos, with a higher incidence of extended (>15 min) surface intervals. Dive depth was bimodal with deep (>31m) and shallow (