Summary
The largest animal known to have ever lived, reaching ~33 m and over 150 tonnes. Cosmopolitan distribution across all major oceans, with seasonal migrations between high-latitude feeding grounds and lower-latitude breeding areas. Listed as Endangered by IUCN; populations are recovering slowly from 20th-century industrial whaling but remain a small fraction of pre-whaling abundance.
Distribution
Sighted across Southern Ocean, North Atlantic — cold temperate, and North Pacific — cold temperate. Pygmy blue whales (B. m. brevicauda) are concentrated in the Indian Ocean and southeast Pacific. Surveys note seasonal aggregations near Stellwagen Bank National Marine Sanctuary (north-west Atlantic feeding) and Pelagos Sanctuary (Mediterranean).
Threats
Primary contemporary threats:
- Ship strikes — vessel collisions in shipping lanes that
overlap migration corridors.
- Entanglement in fishing gear, especially set-net and trap
lines.
- Ocean noise — interferes with low-frequency vocal
communication used for mate finding and group cohesion.
The species is still recovering from Historical whaling, which removed >99% of southern-hemisphere blue whales between ~1900 and the 1966 international moratorium.
Related species
- Fin whale (Balaenoptera physalus) — fin whale, congener; second-largest
cetacean.
acoustic detection often co-occurs.
ship-strike risk in coastal-shelf waters.
Sources
Generated 2026-05-11 from OBIS — Ocean Biodiversity Information System, WoRMS — World Register of Marine Species, IUCN Red List, and FishBase. See frontmatter for the IUCN assessment year and OBIS occurrence snapshot date.