Antarctic Blue Whale (B. m. intermedia)

node · earth · Southern Ocean and adjacent temperate South Atlantic, Indian and Pacific sectors

The largest subspecies, feeding in the Southern Ocean in the austral summer and the principal target of twentieth-century Antarctic whaling. Published reconstructions put pre-exploitation abundance in the low hundreds of thousands - Branch and colleagues report figures around 239,000 in one Bayesian reconstruction and around 256,000 in another, with wide and overlapping confidence intervals - against which the population was reduced to well under one percent. A capture-recapture analysis published in 2025 using photo-identification collected between 2003/04 and 2018/19 gives a POPAN superpopulation estimate of 3,506 whales (95% CI 2,107-5,832) and an abundance in the final survey year of 1,817 (95% CI lower bound 714). It remains assessed as Critically Endangered. It is also the least tracked: only two satellite tracks of Antarctic blue whales existed at the time of the 2023 data publication describing them.