Antipodean albatross spatial distribution and fisheries overlap (WCPFC)
Bycatch in fisheries has been identified as the greatest known threat to the endangered Antipodean albatross (Diomedea antipodensis antipodensis), which is declining at 5% per year. We report on the second year of intensive satellite tracking, with 40 tags deployed on adult males and females during 2020, supplementing 63 tracked birds in 2019 (consisting of adult males, adult females, and juveniles). For each bird location obtained, we estimated the daily overlap with fishing effort, using individual vessel data derived by Global Fishing Watch primarily from AIS data. These methods allowed us to quantify the overlap by geographic or jurisdictional area, year, and season. Over both years, overlap with fishing activity was highest for pelagic longline fishing effort, primarily in the high seas of the Western Pacific, particularly in the mid-Tasman Sea and north-east of New Zealand. Adult females had higher overlap with pelagic longline fishing effort compared to males, which corresponded to recent research showing a higher relative reduction in female survival as an important driver of the Antipodean albatross population decline. In 2020, foraging ranges extended further north than in 2019, with birds travelling up to 21°S, where there are no mandatory requirements for seabird bycatch mitigation use under WCPFC. Almost all birds that were tracked for six months or longer overlapped with at least one pelagic longline fishing vessel. Individual birds were found to overlap with as many as 88 different pelagic longline vessels per year, increasing their potential exposure to bycatch risk. Some individual vessels overlapped with up to a third of tracked birds in a given year. In 2019 one tracked bird was known to be bycaught on a high seas pelagic longline vessel, and the tag was returned. Examination of tracks from other birds that stopped transmitting unexpectedly suggest some may also have been bycaught, but not reported. Further tracking of Antipodean albatross in 2021 and beyond will provide an expanded dataset to further improve our understanding of interannual variation and provide greater certainty on the range of fisheries that pose bycatch risk to this endangered seabird.