Photo-Identification Cataloguing

node · earth · Applied wherever blue whales are surveyed

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.