Photo-Identification Cataloguing

Assembled from 13 blocks · 2 evidence · 5 related

1. Story
2. Identifying individual whales from natural markings - in blue whales, the mottled pigmentation pattern of the flanks - and matching them across years and places to build a capture-recapture history. It is the method behind almost every abundance estimate for the Antarctic subspecies: the Antarctic Blue Whale Catalogue holds 552 individuals, of which 119 were added by the SORP dedicated voyages of 2013, 2015 and 2019, and the 2025 capture-recapture estimate rests on that catalogue. It is also the method behind the South Georgia recovery signal, where 41 blue whales were photo-identified between 2011 and 2020, 23 of them during the 2020 survey alone. Because it needs an animal at the surface in front of a camera, it is slow, and the sample sizes stay small.
3. Knowledge
4. Photo-Identification Cataloguing
5. Connections
6. IWC Southern Ocean Research Partnership
7. Dedicated Antarctic Blue Whale Project voyages
8. Blue whales are found back at South Georgia
9. A capture-recapture abundance estimate for Antarctic blue whales is published
10. An individual Antarctic blue whale is re-sighted at South Georgia
11. Evidence
12. A POPAN superpopulation estimate from Antarctic blue whale photo-identification collected between 2003/04 and 2018/19 gives 3,506 whales (95% CI 2,107-5,832), with abundance in the final study year, 2018/19, estimated at 1,817 (95% CI lower bound 714); SORP voyages in 2013, 2015 and 2019 added 119 individuals to an Antarctic Blue Whale Catalogue totalling 552. V55 verification basis: these figures were returned in the search result carrying the published abstract text and attributed to this paper.
13. Industrial whaling off South Georgia between 1904 and 1971 killed 42,698 blue whales there; more than 34,000 km of systematic survey between 1998 and 2018 produced only a single blue whale sighting; a 2020 survey using visual line transects and DIFAR sonobuoys produced 58 blue whale sightings from 2,430 km of visual effort with 23 individuals photo-identified, and 41 individuals were photo-identified from South Georgia in total between 2011 and 2020. V55 verification basis: these figures were returned in the search result carrying the journal abstract and attributed to this paper.