This report outlines components of the New Zealand sea lion (Phocarctos hookeri, ‘sea lion’) population monitoring work on the Auckland Islands as a part of the wider New Zealand sea lion Threat Management Plan.
During the 2018/19 field season, a total pup production estimate of 1679 was acquired for sea lion colonies at Enderby Island (Sandy Bay 319, South East Point 0), Dundas Island (1295) and Figure of Eight Island (65). This estimate is 6% lower than the 2017/18 estimate of 1792; 44% lower than the peak pup count of 3021 in 1997/98, and 12% higher than the lowest recorded pup count of 1501 in 2008/09. The 2018/19 estimate appears to continue a relatively stable trend over the past 11 years following steady declines since the 1990s.
Flipper tags and microchips were used to permanently mark 767 pups (312 at Enderby, 400 at Dundas, and 55 at Figure of Eight). One hundred pups on each of Enderby and Dundas Islands were weighed and measured.
The population monitoring conducted in 2018/19 also included 44 daily counts of sealions at Sandy Bay, six whole-island sea lion counts of Enderby Island, and 3296 total tag resightings acquired from the Auckland Islands (once matching occurred to remove any resights that were not comparable to an existing tag). Sea lion pup mortality investigations for 2018/19 is reported separately. The project outputs contribute to the ongoing study to inform management decisions for the species in the future.