Australian And New Zealand Fur Seals At The Skerries, Victoria: Recovery Of A Breeding Colony

Abstract

The population size of Australian fur seals Arctocephalus pusillus doriferus and New Zealand fur seals A. forsteri at The Skerries, Victoria was estimated in two consecutive breeding seasons, 1999-2000 and 2000-2001 using both mark-recapture procedures and aerial surveys. 675 and 746 A. p. doriferus pups and 37 and 47 A. forsteri pups were captured and marked in 1999-2000 and 2000-2001, respectively. Resights (1999-2000 N = 3; 2000-2001 N = 6) were conducted 2 - 3 days after marking and pup population estimates were calculated using a modified Lincoln-Petersen estimate. The arithmetic mean for A. p. doriferus pup abundance was 1,867 in the first season and 2,237 in the second. A. forsteri abundance was 75 and 78, respectively. The A. p. doriferus population is estimated to have increased an average of 19.7% (r = 0.18) between 1999 and 2000. The arithmetic mean from five counts of aerial photographs of total animals present at the colony was 1,758 in 1999-2000 and 2,965 in 2000-2001. Due to high variation between counts, aerial surveys proved to be an inconsistent and inaccurate method for estimating the population of fur seals at The Skerries.