Project Title: Australian fur seal pup production and population trends
Chief Investigators: Dr Roger Kirkwood and Dr John Arnould
We estimated the number of live Australian fur seal pups at all breeding sites following the pupping season of November-December 2007 to be 21,882 ± 187 (mean ± se). This total represents a 2.0% annual rate of increase since the 2002 estimate of 19,820 pups. Previously, pup production between 1986 and 2002 had increased at 5.1% per year, so we recorded a continued increase but at a reduced rate.
Pups were recorded at 17 locations; 10 previously known colony sites, 3 newly recognised colonies and 7 haul-out sites where pups are occasionally born. Two colonies adjacent to the Victorian coast account for 51% of total pup production; Seal Rocks (5,660 pups, 25.9%) and Lady Julia Percy Island (5,574 pups, 25.5%). A further three colonies, two Victorian and one in Tasmanian Bass Strait, produced a further 37% of pup production; Kanowna Island (2,913, 13.3%), The Skerries (2,705, 12.4%) and Judgment Rocks (2,387, 10.9%). The remaining pup production (12%) was mainly at other Tasmanian Bass Strait islands. The three newly recognised colonies were; Wright Rocks (130 pups) and Double Island (51 pups) in Tasmanian Bass Strait, and North Casuarina Island (28 pups), near Kangaroo Island, South Australia.
With >50% of pup production at just two colonies, the Australian fur seal remains vulnerable. However, after confinement to 9 colony sites for over 100 years (prior to 2002), there are now 13 established colonies of Australian fur seals, suggesting the species vulnerability is reducing.
Between 1986 and 2002, the species distribution concentrated more toward the northern extent of its range, with pups born at Victorian colonies constituted 61% and 79%, respectively, of the total, and has remained with this pattern, with 78% of pups at Victorian colonies in 2007. The establishment of a colony at North Casuarina Island, South Australia, represents a substantial change to the breeding range of the species, the first movement away from Bass Strait.
