132 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 1. 1978 WEDDELL SEAL HARVESTING AT SCOTT BASE

• Main Author: M. C. Crawley
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: McMurdo Sound; New Zealand; Scott Base; Stirling; Weddell; Weddell Seal
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.410.4753; http://www.newzealandecology.org/nzje/free_issues/NZJEcol1_132.pdf

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 1970-76 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.