New Zealand Journal of Ecology (1978) 1: 132- 137

Weddell seal harvesting at Scott Base, McMurdo Sound, Antarctica, 1970–76

Research Article
M. C. Crawley  
  1. Zoology Department, University of Canterbury, Christchurch, New Zealand

Weddell seals (Leptonychotes weddelli) have been killed annually since 1956 at Scott Base, McMurdo Sound, Antarctica, to provide food for the resident husky dogs. Between 1970 and 1976 personnel of Antarctic Division, DSIR, killed 399 seals, recorded infonnation on their physical characteristics and collected jaws and reproductive organs (females only). Data made available to the Zoology Department, University of Canterbury, for analysis included 321 seal data-sheets, 186 lower jaws and 103 sets of female reproductive organs. The overall sex ratio of seals killed was 1: 1. Mean ages of males ranged from 6.75 years (1972) to 13 years (1975), with an overall mean of 10.4 years; mean ages of females ranged from 7.82 years (1973) to 12 years (1974) with an overall mean of 9.87 years. In the four seasons with adequate sample sizes (15 + animals) the proportion of animals 10 years and older in the samples ranged from 28% (1972) to 65.7% (1976). The mean body lengths of males declined from 260.63 cm in 1970 to 239.8 cm in 1976. Lengths of females fluctuated from year to year between values of 258.25 cm (1974) and 249.28 cm (1975). The thickness of subcutaneous fat on the chest of males in the years 1974-76 ranged from 4.43 cm to 5.16 cm; that of females varied from 4.98 cm to 5.78 cm. The overall pregnancy rate was 65%, with a range from 55% (1974) to 76.5% (1976). Comparison with data from seal kills in 1957, 1962-64 and 1966-68 (Stirling, 1971a) suggests that in the 197()'76 period the Weddell seal population of eastern McMurdo Sound was close to stability, but fluctuating slightly from year to year, probably in response to changes in availability of food and other resources.