STATISTICAL METHODS FOR ESTIMATING NUMBERS OF CAPE FUR SEAL PUPS FROM AERIAL SURVEYS

The Cape fur seal Arctocephalus pusillus of South Africa and Namibia breeds in 23 colonies. Aerial surveys have been used to estimate numbers of pups during breeding seasons from December 1971 to December 1978, and the results have been presented by Shaughnessy (1987). In this paper we develop statistical methods for estimating these pup numbers, as well as variances of the estimates. We demonstrate a significant increase in numbers of seal pups between 1971 and 1976; the rate of increase is estimated to be 3.2% per annum.