Fine scale overlap analysis of Antipodean and Gibson’s albatross with pelagic longline fishing effort

The Antipodean (Diomedea antipodensis antipodensis) and Gibson’s Albatross (D. a. gibsoni) are two declining populations of high conservation concern, one of which is already recognized as an ACAP High Priority Population. Both populations are particularly vulnerable to bycatch in commercial fisheries, as highlighted in recent fisheries risk assessments. This paper provides insights from four years (2019-22) of PTT satellite tracking of 153 Antipodean Albatross and four years (2019, 2022-24) of GPS/PTT satellite tracking of 82 Gibson albatross. For both populations, tracking data comprised of adult and juvenile cohorts, and was used alongside Automated Identification System (AIS) data, sourced from Global Fishing Watch, to assess spatiotemporal overlap of tracked birds with pelagic longline fishing effort. Our findings indicate that i) the range of tracked Antipodean and Gibson’s albatross were largely consistent across years, ii) the spatial distribution of birds differed between populations and age status - with Antipodean albatross primarily utilizing the waters off the east coast of Aotearoa New Zealand through to the coastal waters of Chile and Gibson’s albatross more concentrated in the central Tasman Sea and the Great Australian Bight, iii) 77% of the 235 tracked birds in this study (115 Antipodean Albatross and 65 Gibson’s Albatross) overlapped with fishing vessels, iv) the areas of highest bird-vessel overlap occurred in High Seas areas of CCSBT and WCPFC and v) albatrosses overlapped with pelagic longline fishing vessels of eight key flag states.